ELECTRICAL KNOWLEDGE

CONDUCTOR DAN NONCONDUCTOR

noreply@blogger.com (Jemsguns) — Sun, 7 Feb 2016 11:02:00 +0700

Bila material kelistrikan dikelompokkan, maka akan terdapat tiga kelompok yaitu; Conductor yang dapat menghantarkan arus listrik dengan baik, Nonconductor yaitu meterial yang tidak menghatarkan listrik dan Semiconductor merupakan material yang memliki daya hantar menengah yaitu diantara conductor dan nonconductor. karakteristiknya ditentukan oleh konfigurasi elektronik berdasarkan struktur material atom.

1) Conductor:

Conductor dapat menghantarkan arus listrik dengan baik. Banyak logam yang dapat menghantarkan arus listrik dan elektron dengan baik. Urutan conductor dari yang paling baik adalah sebagai berikut:

Perak > tembaga > emas > aluminium > tungsten > seng > nickel dst.

2) Nonconductor:

Tidak dapat menghantarkan arus listrik Nonconductor disebut juga dengan insulator karena electron bebas tidak mudah dialirkan oleh material tersebut seperti; keramik, gelas, karet, plastik, kayu, dst.

3) Semiconductor:

Semiconductor memiliki karakteristik menengah diantara conductor dan nonconductor. Yang termasuk material semiconductor adalah; silicon (Si), germanium (Ge), selenium (Se) dan sebagainya, yang banyak digunakan pada komponen electronic Untuk wiring mobil , dipakai tipe multiserat yang di dalamnya terdapat berisi kabel tembaga.

Ketebalan kawatnya ditentukan oleh besarnya arus listrik yang dialirkan, beban, kontinuitas, temperatur dan sebagainya. Semakin besar arus listriknya, maka semakin besar kawat yang digunakan dan waktu mengalirkannya juga semakin lama, kawat listrik yang lebih kecil juga bisa dipakai.

DIODE ( Penyearah )

noreply@blogger.com (Jemsguns) — Thu, 4 Feb 2016 18:47:00 +0700

Diode adalah bagian komponen semiconductor yang berfungsi menglirkan arus listrik dalam satu arah. diode secara khusus diperuntukan untuk arus listrik yang mengalir dalam satu arah. Silicon paling banyak digunakan sebagai material semiconductor, selain itu juga ada bahan germanium dan selenium.

Fungsi utama diode adalah menyearahkan arus listrik untuk mengalir hanya dalam satu arah. Juga banyak digunakan untuk fungsi lainnya sebagai berikut :

Digunakan sebagai penyearah arus listrik yaitu mengubah arus bolak balik menjadi arus searah pada sistem pengisian.
Digunakan sebagai pendeteksi untuk menangkap signal frequency radio.
Digunakan pada switch pengatur arus listrik ON/OFF
Mencegah arus balik
Melindungi sirkuit

Selain itu diode digunakan secara luas dengan berbagai ukuran sesuai macam dan kegunaannya.

Cara Kerja Diode ada dua :

Diode arah maju untuk penyearah depan
Diode arah mundur untuk penyearah belakang

A. Diode arah maju untuk penyearah depan

Diode jenis ini dibuat dengan dua terminal pada kedua sisinya yaitu P-N junction semiconductor dengan karakteristik mengalirkan arus listrik hanya dalam satu arah. Pada arah depan sesuai dengan gambar dibawah bila tegangan positive (+) dipasang pada semiconductor jenis P dan tegangan negative (-) dipasang pada semiconductor tipe N, maka hole dan electron berlawanan pada sumber listrik kemudian potensi pemisah perbedaan listrik rendah dan juga lapisan deplesi juga dikecilkan. Akibatnya hole dan electron memungkinkan bergerak bersebrangan melewati permukaan junction. Arus listrik mengalir bersamaan dengan pergerakan hole dan electron.

Sirkuit diode arah maju

Lampu menyala karena diode dihubungkan sesuai dengan arah arus listrik.

B.Diode arah mundur untuk penyearah belakang

Mari kita lihat pemasangan arah tagangan negative (-) pada semiconductor tipe P dan tegangan positive (+) pada semiconductor tipe N. Kemudian semiconductor P di hubungkan dengan sumber tegangan negative (-), sebaliknya semiconductor N dihubungkan dengan sumber tegangan positive (+). Akibatnya pembatas potensial meningkat dan secara bersamaan lapisan deplesi juga melebar sehingga electron tidak dapat bergerak melewati antara kedua jenis semiconductor. Akibatnya arus listrik tidak dapat mengalir.

Sirkuit diode arah balik.

Lampu tidak menyala karena diode dihubungkan berlawanan arah arus listrik sepert pada gambar dibawah ini.

Demikian sedikit ulasan saya mengenai fungsi dasar dari Dioda.

KOMPOSISI DAN INTI KELISTRIKAN ( INDONESIA LANGUANGE )

noreply@blogger.com (Jemsguns) — Wed, 3 Feb 2016 19:24:00 +0700

Setiap benda terdiri dari molekul-molekul dimana dalam pergerakannya secara kimia merupakan gabungan atom-atom yang konstan.

Seperti pada gambar diatas, elektron-elektron bergerak dengan cepat disekitar inti atom,
mengelilingi orbitnya, seperti bumi dan planet-planet yang mengitari matahari. Hanya sejumlah elektron tertentu yang dapat keluar orbitnya (K: 2, L: 8, M: 18, . . .) dan setiap elemen memiliki karakter jumlah elektron (contoh. hydrogen 1, carbon 6, oxygen 8,...).

Umumnya inti atom memiliki muatan listrik positif (+) dan elektron memiliki muatan listrik negati (-) dan keduanya memiliki sifat saling tarik menarik satu sama lainnya sehingga atom menjadi netral (jumlah muatan positif = jumlah muatan negatif). Dikarenakan gaya tarik menarik dari inti atom terhadap elektron yang berada diluar orbit (valence electron) atau yang paling lemah, maka elektron tersebut mudah lepas dari orbitnya karena pengaruh luar (seperti panas, kelistrikan, cahaya dsb.) sehingga bisa pindah ke orbit lainnya, Elektron-elektron yang keluar dari orbit tersebut disebut dengan elektron bebas, dan merupakan inti dari listrik.

Perpindahan elektron bebas tersebut selanjutnya menjadi arus listrik. Jadi pergerakan elektron bebas ini merupakan aliran arus listrik.

Estimation of Plant Electrical Load

noreply@blogger.com (Jemsguns) — Fri, 14 Oct 2011 09:18:00 +0700

One of the earliest tasks for the engineer who is designing a power system is to estimate the normal

operating plant load. He is also interested in knowing how much additional margin he should include

in the final design. There are no ‘hard and fast’ rules for estimating loads, and various basic questions

need to be answered at the beginning of a project, for example,

• Is the plant a new, ‘green field’ plant?

• How long will the plant exist e.g. 10, 20, 30 years?

• Is the plant old and being extended?

• Is the power to be generated on site, or drawn from an external utility, or a combination of both?

• Does the owner have a particular philosophy regarding the ‘sparing’ of equipment?

• Are there any operational or maintenance difficulties to be considered?

• Is the power factor important with regard to importing power from an external source?

• If a generator suddenly shuts down, will this cause a major interruption to the plant production?

• Are there any problems with high fault levels?

1.1 PRELIMINARY SINGLE-LINE DIAGRAMS

In the first few weeks of a new project the engineer will need to roughly draft a key single-line

diagram and a set of subsidiary single-line diagrams. The key single-line diagram should show the

sources of power e.g. generators, utility intakes, the main switchboard and the interconnections to

the subsidiary or secondary switchboards. It should also show important equipment such as power

transformers, busbars, busbar section circuit breakers, incoming and interconnecting circuit breakers,

large items of equipment such as high voltage induction motors, series reactors for fault current

limitation, and connections to old or existing equipment if these are relevant and the main earthing

arrangements. The key single-line diagram should show at least, the various voltage levels, system

frequency, power or volt-ampere capacity of main items such as generators, motors and transformers,

switchboard fault current levels, the vector group for each power transformer and the identification

names and unique ‘tag’ numbers of the main equipment.

The set of single-line diagrams forms the basis of all the electrical work carried out in a

particular project. They should be regularly reviewed and updated throughout the project and issued

in their final form at the completion of the project. They act as a diary and record the development

of the work. Single-line diagrams are also called ‘one-line diagrams’.

At this stage the engineer can begin to prepare a load schedule for each subsidiary switchboard

and motor control centre, and a master schedule for the main switchboard. The development of the

single-line diagrams during the project is discussed.

The master load schedule will give an early estimate of the total power consumption. From

this can be decided the number of generators and utility intakes to install. The kW and kVA ratings

of each generator or intake will be used to determine the highest voltage to use in the power

system. Table 1.1 shows typical voltages used throughout the world for generation, distribution and

transmission of power at oil industry plants.

1.2 LOAD SCHEDULES

Each switchboard will supply power to each load connected to it and in many cases it will also supply

power to switchboards or distribution boards immediately downstream. Hence the input power to a switchboard will have the possibility of two components, one local and one downstream. Hereinafter

the term switchboard will also include the term motor control centre, see sub-section 7.1.

Each local load may be classified into several different categories for example, vital, essential

and non-essential. Individual oil companies often use their own terminology and terms such as

‘emergency’ and ‘normal’ are frequently encountered. Some processes in an oil installation may

handle fluids that are critical to the loss of power e.g. fluids that rapidly solidify and therefore must

be kept hot. Other processes such as general cooling water services, air conditioning, sewage pumping

may be able to tolerate a loss of supply for several hours without any long-term serious effects.

In general terms there are three ways of considering a load or group of loads and these may

be cast in the form of questions. Firstly will the loss of power jeopardise safety of personnel or

cause serious damage within the plant? These loads can be called ‘vital’ loads. Secondly will the loss

of power cause a degradation or loss of the manufactured product? These loads can be called the

‘essential’ loads. Thirdly does the loss have no effect on safety or production? These can be called

the ‘non-essential’ loads.

Vital loads are normally fed from a switchboard that has one or more dedicated generators

and one or more incoming feeders from an upstream switchboard. The generators provide power

during the emergency when the main source of power fails. Hence these generators are usually

called ‘emergency’ generators and are driven by diesel engines. They are designed to automatically

start, run-up and be closed onto the switchboard whenever a loss of voltage at the busbars of the

switchboard is detected. An undervoltage relay is often used for this purpose. Testing facilities are

usually provided so that the generator can be started and run-up to demonstrate that it is ready to

respond when required. Automatic and manual synchronising facilities can also be provided so that

the generator can be loaded during the tests.

Low voltage diesel generators are typically rated between 100 and 500 kW, and occasionally

as large as 1000 kW. High voltage emergency generator ratings are typically between 1000 and

2500 kW. The total amount of vital load is relatively small compared with the normal load and, in

many situations, the essential load. Consequently the vital load is fed from uninterruptible power

supplies (UPS), as AC or DC depending upon the functions needed. The vital loads are usually fed

from a dedicated part of the emergency switchboard. The UPS units themselves are usually provided

with dual incoming feeders, as shown in Figure 17.3.

Some of the vital and essential loads are required when the plant is to be started up, and there

is no ‘normal’ power available. In this situation the starting up of the plant is called ‘black starting’.

The emergency generator must be started from a source of power, which is usually a high capacity

storage battery and a DC starter motor, or a fully charged air receiver and a pneumatic starter motor.

In many plants, especially offshore platforms, the vital and essential loads operate at low

voltage e.g. 380, 400, 415 volts. Large plants such as LNG refrigeration and storage facilities require

substantial amounts of essential power during their start-up and shut-down sequences and so high

voltage e.g. 4160, 6600 volts is used. The vital loads would still operate at low voltage. Tables 1.2

and 1.3 shows typical types of loads that can be divided into vital and essential loads.

All of the vital, essential and non-essential loads can be divided into typically three duty categories:

• Continuous duty.

• Intermittent duty.

• Standby duty (those that are not out of service).

Hence each switchboard will usually have an amount of all three of these categories. Call

these C for continuous duty, I for intermittent duty and S for the standby duty. Let the total amount

of each at a particular switchboard j be ( Cjsum, Ijsum and Sjsum ). Each of these totals will consist of

the active power and the corresponding reactive power.

In order to estimate the total consumption for the particular switchboard it is necessary to

assign a diversity factor to each total amount. Let these factors be ( Dcj for Csumj , Dij for Isumj ). Oil companies that use this approach have different values for their diversity factors,

largely based upon experience gained over many years of designing plants. Different types of plants

may warrant different diversity factors. Table 1.4 shows the range of suitable diversity factors. The factors should be chosen in such a manner that the selection of main generators and main feeders from

a power utility company are not excessively rated, thereby leading to a poor choice of equipment in

terms of economy and operating efficiency.

The above method can be used very effectively for estimating power requirements at the

beginning of a new project, when the details of equipment are not known until the manufacturers can

offer adequate quotations. Later in a project the details of efficiency, power factor, absorbed power,

rated current etc. become well known from the purchase order documentation. A more accurate form

of load schedule can then be justified. However, the total power to be supplied will be very similar

when both methods are compared.

The total load can be considered in two forms, the total plant running load (TPRL) and the

total plant peak load (TPPL), hence,

Where n is the number of switchboards.The installed generators or the main feeders to the plant must be sufficient to supply the TPPL

on a continuous basis with a high load factor. This may be required when the production at the plant

is near or at its maximum level, as is often the case with a seasonal demand.

Where a plant load is predominantly induction motors it is reasonable to assume the overall

power factor of a switchboard to be 0.87 lagging for low voltage and 0.89 lagging for high voltage

situations. If the overall power factor is important with regard to payment for imported power, and

where a penalty may be imposed on a low power factor, then a detailed calculation of active and

reactive powers should be made separately, and the total kVA determined from these two totals. Any

necessary power factor improvement can then be calculated from this information.

1.2.1 Worked Example

An offshore production and drilling platform is proposed as a future project, but before the detail

design commences it is considered necessary to prepare an estimate of the power consumption. The

results of the estimate will be used to determine how many gas-turbine driven generators to install.

This in turn will enable an initial layout of all the facilities and equipment to be proposed. Since this is

a new plant and the preliminary data is estimated from process calculations, mechanical calculations

and comparisons with similar plants, it is acceptable to use the following diversity factors, Dc = 1.0,

Di = 0.5 and Ds = 0.1.

Tables 1.5, 1.6, 1.7 and 1.8 show the individual loads that are known at the beginning of

the project.

The total power is found to be 12,029 kW. At this stage it is not known whether the plant is

capable of future expansion. The oil and gas geological reservoir may not have a long life expectation,

and the number of wells that can be accommodated on the platform may be limited. The 4000 kW

of power consumed by the drilling operations may only be required for a short period of time e.g.

one year, and thereafter the demand may be much lower.

During the detail design phase of the project the load schedules will be modified and additional

loads will inevitably be added. At least 10% extra load should be added to the first estimate i.e.

1203 kW. The total when rounded-up to the nearest 100 kW would be 13,300 kW.

Sufficient generators should be installed such that those that are necessary to run should be

loaded to about 80 to 85% of their continuous ratings, at the declared ambient temperature. This

subject is discussed in more detail in sub-section 1.3. If four generators are installed on the basis that

one is a non-running standby unit, then three must share the load. Hence a reasonable power rating

for each generator is between 5216 kW and 5542 kW.

Formula for Voltage Drop

noreply@blogger.com (Jemsguns) — Fri, 14 Oct 2011 08:44:00 +0700

Electrical Formula

noreply@blogger.com (Jemsguns) — Wed, 5 Oct 2011 19:40:00 +0700

Add caption

Cable Tray Installation Guidelines

noreply@blogger.com (Jemsguns) — Wed, 5 Oct 2011 19:29:00 +0700

COMMON TOOLS FOR INSTALLATION

The following tools are commonly used for installation of cable tray:

• Metal cutting saw

• Leveling device

• Touch-up material

• Tape measure

• Screwdriver

• Square

• Drill with bits

• C-clamp

• File

• Torque wrench

• Open end wrech

• Ratchet wrench

• Nylon cord or laser

• Offset Bolt cutters (Wire mesh)

• Sealant for cut edges (Fiberglass)

• Dust Mask (Fiberglass)

• Cutting Saw (Fiberglass) Carbide or Diamond Tipped

• Appropriate safety equipment

SUPPORT INSTALLATION
Caution! Do not cut or drill structural building members (e.g. I-beams) without approval by the general
contractor.

In order to install the cable tray supports, first find the required elevation from the floor to the bottom of

the cable tray and establish a level line with a laser or a nylon string. A string works well because it can

be used to align the threaded rods on one side of a trapeze and find the tops of the supports.

In order to speed the process of installing the trapeze hangers, some nuts may be pre-threaded onto the

threaded rod to the approximate location where the nut will be needed. One method for pre-threading the

nuts is to put the nuts onto the end of a piece of threaded rod, attach a drill to the threaded rod, and run

the nuts up the rod holding onto them with an open-end wrench.

NOTE—Nonmetallic supports and hardware may require special load bearing considerations due to material

composition and application temperature. Consult the cable tray manufacturer for recommended practices.

Cable Tray Supports

Caution! Supports for cable trays should provide strength and working load capabilities sufficient to meet

the load requirement of the cable tray wiring system. Consideration should be given to the loads

associated with future cable additions or any other additional loads applied to the cable

tray system or the cable trays support system.

NOTE—Nonmetallic supports and hardware may require special load bearing considerations due to material

composition and application temperature.

NOTE—Special consideration may be required for center-supported systems considering eccentric loading.

Boiler Instrument and Control Part 1

noreply@blogger.com (Jemsguns) — Wed, 5 Oct 2011 15:46:00 +0700

INTRODUCTION

Instrumentation and controls in a boiler plant encompass an
enormous range of equipment from simple industrial plant to the complex
in the large utility station.

The boiler control system is the means by which the balance of
energy & mass into and out of the boiler are achieved. Inputs are fuel,
combustion air, atomizing air or steam &feed water. Of these, fuel is the
major energy input. Combustion air is the major mass input, outputs are
steam, flue gas, blowdown, radiation & soot blowing.

CONTROL LOOPS

Boiler control systems contain several variable with interaction
occurring among the control loops for fuel, combustion air, & feedwater .
The overall system generally can be treated as a series of basic control
loops connected together. for safety purposes, fuel addition should be
limited by the amount of combustion air and it may need minimum limiting
for flame stability.

Combustion controls

Amounts of fuel and air must be carefully regulated to keep excess
air within close tolerances-especially over the loads. This is critical to
efficient boiler operation no matter what the unit size, type of fuel fired or
control system used.

Feedwater control

Industrial boilers are subject to wide load variations and require
quick responding control to maintain constant drum level. Multiple element
feed water control can help faster and more accurate control response.

Estimation of Plant Electrical Load ( Part 2 )

noreply@blogger.com (Jemsguns) — Tue, 23 Feb 2010 07:22:00 +0700

LOAD SCHEDULE
Each switchboard will supply power to each load connected to it and in many cases it will also supply
power to switchboards or distribution boards immediately downstream. Hence the input power to aswitchboard will have the possibility of two components, one local and one downstream. Hereinafter
the term switchboard will also include the term motor control centre, see sub-section 7.1.
Each local load may be classified into several different categories for example, vital, essential
and non-essential. Individual oil companies often use their own terminology and terms such as
‘emergency’ and ‘normal’ are frequently encountered. Some processes in an oil installation may
handle fluids that are critical to the loss of power e.g. fluids that rapidly solidify and therefore must
be kept hot. Other processes such as general cooling water services, air conditioning, sewage pumping
may be able to tolerate a loss of supply for several hours without any long-term serious effects.
In general terms there are three ways of considering a load or group of loads and these may
be cast in the form of questions. Firstly will the loss of power jeopardise safety of personnel or
cause serious damage within the plant? These loads can be called ‘vital’ loads. Secondly will the loss
of power cause a degradation or loss of the manufactured product? These loads can be called the
‘essential’ loads. Thirdly does the loss have no effect on safety or production? These can be called
the ‘non-essential’ loads.
Vital loads are normally fed from a switchboard that has one or more dedicated generators
and one or more incoming feeders from an upstream switchboard. The generators provide power
during the emergency when the main source of power fails. Hence these generators are usually
called ‘emergency’ generators and are driven by diesel engines. They are designed to automatically
start, run-up and be closed onto the switchboard whenever a loss of voltage at the busbars of the
switchboard is detected. An undervoltage relay is often used for this purpose. Testing facilities are
usually provided so that the generator can be started and run-up to demonstrate that it is ready to
respond when required. Automatic and manual synchronising facilities can also be provided so that
the generator can be loaded during the tests.
Low voltage diesel generators are typically rated between 100 and 500 kW, and occasionally
as large as 1000 kW. High voltage emergency generator ratings are typically between 1000 and
2500 kW. The total amount of vital load is relatively small compared with the normal load and, in
many situations, the essential load. Consequently the vital load is fed from uninterruptible power
supplies (UPS), as AC or DC depending upon the functions needed. The vital loads are usually fed
from a dedicated part of the emergency switchboard. The UPS units themselves are usually provided
with dual incoming feeders, as shown in Figure 17.3.
Some of the vital and essential loads are required when the plant is to be started up, and there
is no ‘normal’ power available. In this situation the starting up of the plant is called ‘black starting’.
The emergency generator must be started from a source of power, which is usually a high capacity
storage battery and a DC starter motor, or a fully charged air receiver and a pneumatic starter motor.
In many plants, especially offshore platforms, the vital and essential loads operate at low
voltage e.g. 380, 400, 415 volts. Large plants such as LNG refrigeration and storage facilities require
substantial amounts of essential power during their start-up and shut-down sequences and so high
voltage e.g. 4160, 6600 volts is used. The vital loads would still operate at low voltage. Tables 1.2
and 1.3 shows typical types of loads that can be divided into vital and essential loads.
All of the vital, essential and non-essential loads can be divided into typically three duty categories:
• Continuous duty.
• Intermittent duty.
• Standby duty (those that are not out of service).

Hence each switchboard will usually have an amount of all three of these categories. Call
these C for continuous duty, I for intermittent duty and S for the standby duty. Let the total amount
of each at a particular switchboard j be Cjsum, Ijsum and Sjsum. Each of these totals will consist of
the active power and the corresponding reactive power.
In order to estimate the total consumption for the particular switchboard it is necessary to
assign a diversity factor to each total amount. Let these factors be Dcj for Csumj , Dij for Isumj and
Dsj for Ssumj . Oil companies that use this approach have different values for their diversity factors,
largely based upon experience gained over many years of designing plants. Different types of plants
may warrant different diversity factors. Table 1.4 shows the range of suitable diversity factors. The
factors should be chosen in such a manner that the selection of main generators and main feeders from
a power utility company are not excessively rated, thereby leading to a poor choice of equipment in
terms of economy and operating efficiency.

The above method can be used very effectively for estimating power requirements at the
beginning of a new project, when the details of equipment are not known until the manufacturers can
offer adequate quotations. Later in a project the details of efficiency, power factor, absorbed power,
rated current etc. become well known from the purchase order documentation. A more accurate form
of load schedule can then be justified. However, the total power to be supplied will be very similar
when both methods are compared.
The total load can be considered in two forms, the total plant running load (TPRL) and the
total plant peak load (TPPL), hence,

Where n is the number of switchboards.
The installed generators or the main feeders to the plant must be sufficient to supply the TPPL
on a continuous basis with a high load factor. This may be required when the production at the plant
is near or at its maximum level, as is often the case with a seasonal demand.
Where a plant load is predominantly induction motors it is reasonable to assume the overall
power factor of a switchboard to be 0.87 lagging for low voltage and 0.89 lagging for high voltage
situations. If the overall power factor is important with regard to payment for imported power, and
where a penalty may be imposed on a low power factor, then a detailed calculation of active and
reactive powers should be made separately, and the total kVA determined from these two totals. Any
necessary power factor improvement can then be calculated from this information.

Estimation of Plant Electrical Load ( Part 1 )

noreply@blogger.com (Jemsguns) — Tue, 23 Feb 2010 07:00:00 +0700

One of the earliest tasks for the engineer who is designing a power system is to estimate the normal
operating plant load. He is also interested in knowing how much additional margin he should include
in the final design. There are no ‘hard and fast’ rules for estimating loads, and various basic questions
need to be answered at the beginning of a project, for example,
• Is the plant a new, ‘green field’ plant?
• How long will the plant exist e.g. 10, 20, 30 years?
• Is the plant old and being extended?
• Is the power to be generated on site, or drawn from an external utility, or a combination of both?
• Does the owner have a particular philosophy regarding the ‘sparing’ of equipment?
• Are there any operational or maintenance difficulties to be considered?
• Is the power factor important with regard to importing power from an external source?
• If a generator suddenly shuts down, will this cause a major interruption to the plant production?
• Are there any problems with high fault levels?
1.1 PRELIMINARY SINGLE-LINE DIAGRAMS
In the first few weeks of a new project the engineer will need to roughly draft a key single-line
diagram and a set of subsidiary single-line diagrams. The key single-line diagram should show the
sources of power e.g. generators, utility intakes, the main switchboard and the interconnections to
the subsidiary or secondary switchboards. It should also show important equipment such as power
transformers, busbars, busbar section circuit breakers, incoming and interconnecting circuit breakers,
large items of equipment such as high voltage induction motors, series reactors for fault current
limitation, and connections to old or existing equipment if these are relevant and the main earthing
arrangements. The key single-line diagram should show at least, the various voltage levels, system
frequency, power or volt-ampere capacity of main items such as generators, motors and transformers,
switchboard fault current levels, the vector group for each power transformer and the identification
names and unique ‘tag’ numbers of the main equipment.
The set of single-line diagrams forms the basis of all the electrical work carried out in a
particular project. They should be regularly reviewed and updated throughout the project and issued

in their final form at the completion of the project. They act as a diary and record the development
of the work. Single-line diagrams are also called ‘one-line diagrams’.
At this stage the engineer can begin to prepare a load schedule for each subsidiary switchboard
and motor control centre, and a master schedule for the main switchboard. The development of the
single-line diagrams during the project is discussed in sub-section 1.7.
The master load schedule will give an early estimate of the total power consumption. From
this can be decided the number of generators and utility intakes to install. The kW and kVA ratings
of each generator or intake will be used to determine the highest voltage to use in the power
system. Table 1.1 shows typical voltages used throughout the world for generation, distribution and
transmission of power at oil industry plants, see also sub-section 3.7.

noreply@blogger.com (Jemsguns) — Tue, 29 Dec 2009 08:30:00 +0700

Penggunaan hp dengan fasilitas sms sudah bukan barang asing lagi, hampir semua
orang sudah memanfaatkannya untuk mengirimkan pesan pendek. Proses sms sederhana
saja, dengan mengetikkan pesan dilayar, send ke nomor yang dituju, sampailah
(berharap), atau tidak sampai jika ada gangguan atau terlambat diterima.
Alarm via SMS
Bagaiman jika hp digunakan untuk kendali atau monitoring jarak jauh, mirip
remote control tv?,apa yang bisa dikendalikannya ?, atau dimonitor?, ambil contoh kasus
berikut ini; mobil yang sudah dilengkapi dengan alarm, lalu alarm berbunyi, bisa saja ada
maling atau hanya kesalahan alarm semata, semuanya menimbulkan suara alarm, orang
disekitar biasanya acuh tak acuh dan menganggap itu adalah alarm palsu atau kesalahan
alarm, bukan maling. Jika pemiliknya jauh dari mobil, bisa jadi alarm bunyi terus
menerus ditempat itu atau maling lebih pintar, sudah bisa mematikan alarm dan
membawa kabur mobil. Bagaimana jika mobil bisa kirim sms ke pemiliknya bahwa ada
maling atau kesalahan alarm?, lalu siapakan yang mengirimkan sms tersebut ?, tulisan ini
akan membahas bahwa hal itu dimungkinkan dengan menggunakan perangkat
mikrokontroler dan hp yang mudah didapat dipasaran.
Sebenarnya aplikasi tidak hanya alarm mobil saja, masalah lain misalnya saat ini
sering terdengar berita tentang pembobolan toko yang ditinggal pergi pemiliknya, tidak
dijaga, atau juga sekolah yang kehilangan beberapa set komputer dengan dibobolnya
ruang komputer tanpa berpenjaga. Seandainya dilengkapi dengan alarm sms ini bisa
dilaporkan melalui sms bahwa toko sedang dibobol, pelaporan dapat ke pemilik, satpam
atau ke polisi, sehingga bisa dilakukan tindakan yang lebih cepat.
Akusisi Data
Istilah akusisi data adalah mengirimkan dan mengambil data dari perangkat, bisa
remote jarak jauh. Remote melalui sms bisa jarak jauh bahkan melampaui batas negara,
selama masih ada jaringan GSM, Melalui HP dapat dikendalikan peralatan ditempat lain,
misalnya menyalakan AC, menghidupkan pompa, lampu, atau melihat status / data
temperatur, tekanan, jumlah pengunjung dan sebagainya dari jarak jauh. Dengan
teknologi hp berkamera, dimungkinkan mengambil gambar dari jarak jauh, untuk
mengetahui suasana ditempat lain, ini juga bisa digunakan untuk sistem keamanan.
Mikrokontroller
Tentu saja ditempat remote harus ada hp dan sim card untuk mengirimkan sms,
lalu siapa yang mencet-mencet hp untuk mengirim sms?, bukan orang tetapi perangkat
komputer yang dihubungkan dengan hp, yang dapat memerintahkan mengirim sms atau
membaca sms, sistem komputer yang dihubungkan dengan hp ini sudah banyak
digunakan untuk kuis-kuis interaktif di tv via sms atau polling via sms, jadi operator
(manusia) tidak perlu repot-repot membaca sms dan menghitung hasil polling. Alat yang
sama digunakan untuk mengases informasi prestasi akademik via sms bagi mahasiswa
perguruan tinggi yang melengkapi sistem informasi akademiknya dengan akses sms.
Komputer tidak akan laik jika digunakan di mobil, ditoko atau di industri yang harus
bekerja 24 jam, karena akan terlalu mubasir, terlalu besar. Solusi yang paling tepat adalah
dengan menggunakan mikrokontroler, semacam MCS51 (Intel), AT89C (Atmel), PIC
(Microchip), 68HC11 (Motorla) atau yang lain. Mikroprosesor adalah otak dari
komputer, jadi sebenarnya mikrokontroler adalah komputer mini yang didisain khusus
untuk instrumentasi dan kendali. Selain harganya murah dan sedikit komponen yang
digunakan dan catu daya rendah akan menguntungkan karena sedikit kemungkinan
terjadi gagal.

Beberapa jenis hp, seperti Nokia, Siemens dan Sony memiliki modem (modulation –
demodulation), seperti juga komputer yang memiliki modem untuk mengirimkan data
melalui jaringan telepon. Jadi hp yang memiliki modem akan bisa dikoneksikan ke
komputer melalui kabel data (RS232 atu USB), sehingga dapat berfungsi sebagai
pengirim data, misalnya sebagai fax. Untuk penggunaan mikrokontroler juga
dikoneksikan melalui kabel data dan mikrokontroler akan berkomunikasi dengan hp
melalui kabel ini. Perintah standart modem dikenal dengan istilah AT Command,
perintah ini dapat digunakan untuk mengirim, menerima/membaca dan menghapus sms,
disamping banyak fungsi lagi. Beberapa jenis hp memiliki extended AT Command yang
bisa digunakan untuk mengambil informasi jenis, model hp, nomor IMEI (Internasional
Mobile Station Equipment Identity) , SIM IMSI (Subscriber Identification Number ),
status batere, kekuatan sinyal, nama operator, lokasi dan cell ID.
Format SMS
Jika kita mengirimkan pesan pendek, pesan ini tidak dikirimkan dalam format
yang tertulis, tetapi harus dikonversi lagi menjadi format PDU (Protocol Data Unit)
semacam kompresi data (pemampatan data), selain pesan tersebut, juga ikut dikirimkan
informasi nomor pengirim, nomor penerima, nomor sms center, tanggal dan jam.
Dipenerima format PDU harus dikembalikan lagi menjadi format text yang bisa dibaca
sesuai pesan yang dikimkan, format PDU berupa pergeseran data-data dari format 7 bit
menjadi 8 bit.
Sensor dan aktuator
Sensor akan memberitahukan kepada mikrokontroler bahwa ada sesuatu yang
berubah, misalnya ada orang masuk ruangan atau mobil, ada kebakaran dsb,
mikrokontroler akan berlaku seperti orang mengirim sms dengan adanya perubahan
tersebut atau menggerakkan aktuator berupa alarm, lampu dsb. Aktuator juga dapat
diaktifkan melalui perintah sms, misalnya untuk mengisi batere, menyalakan ac, lampu
dsb.
Sensor yang paling sederhana adalah saklar on-off, dapat dipasang dipintu, jika
pintu dibuka, saklar berubah status. Sensor keberadaan orang adalah PIR (Pyroelectric
Infra Red), yang mendeteksi adanya objek panas yang bergerak (manusia mengeluarkan
panas infra merah), sensor ini banyak digunakan untuk lampu keamanan, jika ada orang
lewat, lampu menyala. Ultrasonic radar juga merupakan salah satu sensor untuk
mendeteksi adanya objek lain (perubahan objek), ini prinsipnya seperti radar. Sensor lain
dapat berupa fire detector (mendeteksi adanya api), smoke detector (asap), tekanan dan
masih banyak lagi.
Deteksi Posisi
Sistem remote sms ini yang dilengkapi dengan GPS (Global Positioning System),
sebuah perangkat yang harganya juga tidak mahal, menerima sinyal dari satelit dan
melaporkan posisi dimana GPS ini berada, baik lintang, bujur maupun ketinggian.
Sebuah kendaraan dapat dimonitor secara jarak jauh sedang berada dimana dengan cara
ini. Sebenarnya tanpa GPS pun juga dapat dimonitor, karena bisa diketahui cell id dan
location, tetapi tidak setepat menggunakan GPS, karena informasi lokasi dalam cakupan
satu cell yang radiusnya sekitar 2-3 km.
Beberapa kelemahan
Yang jelas harus membayar setiap kali mengirim sms, juga kartu memiliki masa
aktif dan kadang sms terlambat atau malah tidak sampai, masalah ini dapat diatasi dengan
menggunakan kartu yang sejenis, sehingga sms dapat segera sampai.

Compressor & Turbine

noreply@blogger.com (Jemsguns) — Wed, 23 Dec 2009 11:30:00 +0700

Effect of an Inefficient Compressor and Turbine
Frictional losses in the compressor raise the output temperature. Similarly the losses in the turbine
raise the exhaust temperature. These losses are quantified by modifying the temperatures T2 and T4
to account for their increases.
The compression ratio (P2/P1) of the compressor is usually given by the manufacturer and
therefore the temperature of the air leaving the compressor is easily found from (2.13). If the efficiency
of compression ηc is known e.g. 90% and that of the turbine ηt is known e.g. 85% then a better
estimate of the output energy can be calculated. In this situation T2 becomes T2e and T4 becomes
T4e, as follows:-
T2e = T2
ηc
+ 1 − 1
ηc
T1 and T4e = T4ηt + (1 − ηt)T3 (2.18)
These would be the temperatures measurable in practice. In (2.14) and (2.15) the pressure
ratios are theoretically equal, and in practice nearly equal, hence:
T2
T1
= T3
T4
= rp
β (2.19)
Where rp is the pressure ratio
P2
P1
or
P3
P4
In practice the temperatures T1 and T3 are known from the manufacturer or from measuring
instruments installed on the machine. The pressure ratio rp is also known. The ratio of specific heats
is also known or can be taken as 1.4 for air. If the compressor and turbine efficiencies are taken into
account then the practical cycle efficiency ηp of the gas turbine can be expressed as:
ηp = T3(1 − rp
δ)ηcηt − T1(rp
β − 1)
T3ηc − T1(rp − 1 + ηc)
(2.20)
which has a similar form to (2.17) for comparison.
2.2.1.1 Worked example
A light industrial gas turbine operates at an ambient temperature T1 of 25◦C and the combustion
temperature T3 is 950◦C. The pressure ratio rp is 10.
If the overall efficiency is 32% find the efficiency of the compressor assuming the turbine
efficiency to be 86%.
From (2.20),
T1 = 273 + 25 = 298◦K
T3 = 273 + 950 = 1223◦K
rp
δ = 10−0.2857 = 0.51796 and rp
β = 10+0.2857 = 1.93063
Therefore,
ηp = 0.32 = 1223(1.0 − 0.51796)ηc(0.86) − 298(1.93063 − 1.0)
1223ηc − 298(1.93063 − 1.0 + ηc)
Transposing for ηc results in ηc = 0.894. Hence the compressor efficiency would be 89.4%.
2.2.2 Maximum Work Done on the Generator
If the temperatures T2e and T4e are used in (2.11) to compensate for the efficiencies of the compressor
and turbine, then it is possible to determine the maximum power output that can be obtained as a
function of the pressure ratio rp.
The revised turbine work done Ute is,
Ute = Cp(T3 − T4)ηt kJ/kg (2.21)
The revised compressor work done Uce is,
Uce = Cp(T2 − T1)
1
ηc
kJ/kg (2.22)
The revised heat input from the fuel Uf e is,
Uf e = Cp(T3 − T2e) kJ/kg (2.23)
where,
T2e = T1 rp
β − 1 + ηc
ηc

From (2.19),
T4 = T3rp
δ (2.24)
and
T2 = T1rp
β (2.25)
Substituting for T2, T2e and T4 gives the resulting output work done Uoute to be,
Uoute = Ute − Uce = Cp(T3 − T3rp
δ)ηt − Cp T1rp
β − T1
ηc

= Cp T3(1 − rδ)ηt − T1
ηc
(rp
β − 1) kJ/kg (2.26)
To find the maximum value of Uoute differentiate Uoute with respect to γp and equate the result
to zero. The optimum value of γp to give the maximum value of Uoute is,
rpmax = T1
T3ηcηt
d
(2.27Where
d = 1
2δ
which when substituted in (2.26) gives the maximum work done Uoutemax.
2.2.2.1 Worked example
Find rpmax for the worked example in sub-section 2.2.1.1.
Given that,
T1 = 298 K, T3 = 1223◦C,
r = 1.4, ηt = 0.86 and ηc = 0.894
d = γ
2(1 − γ )
= 1.4
2(1.0 − 1.4)
= −1.75
rpmax = 298
1223(0.894)(0.86)

−1.75
= 0.3169−1.75 = 7.4
2.2.3 Variation of Specific Heat
As mentioned in sub-section 2.2 the specific heat Cp changes with temperature. From Reference 4,
Figure 4.4, an approximate cubic equation can be used to describe Cp in the range of temperature
300 K to 1300 K when the fuel-to-air ratio by mass is 0.01, and for the air alone for compression, as
shown in Table 2.1. The specific heat for the compressor can be denoted as Cpc and for the turbine
Cpt . The appropriate values of Cpc and Cpt can be found iteratively from the cubic expression and
equations (2.24) and (2.25). At each iteration the average of T1 and T2 can be used to recalculate Cpc,
and T3 and T4 to recalculate Cpt . The initial value of γ can be taken as 1.4 in both cases, and Cv
can be assumed constant at 0.24/1.4 = 0.171 kcal/kg K. The pressure ratio is constant. Having found
suitable values of Cpc and Cpt it is now possible to revise the equations for thermal efficiency ηpa
and output energy Uoutea, where the suffix ‘a’ is added to note the inclusion of variations in specific
heat Cp.
Table 2.1. Specific heat Cp as a cubic function of absolute temperature
K in the range 373 K to 1273 K Cp = a + bT + cT 2 + dT 3
Fuel-air Cubic equation constants
ratio
a × 100 b × 10−4 c × 10−7 d × 10−10
0.0 0.99653 −1.6117 +5.4984 −2.4164
0.01 1.0011 −1.4117 +5.4973 −2.4691
0.02 1.0057 −1.2117 +5.4962 −2.5218
The energy equations for the compressor and turbine become,
Ucea = Cpc(T2 − T1) 1
ηc
kJ/kg (2.28)
and
Utea = Cpt (T3 − T4) 1
ηt
kJ/kg (2.29)
Also assume that the specific heat Cpf of the fuel–air mixture is the value corresponding to
the average value of T2 and T3, see Reference 4, sub-section 4.7.1, (2.23).
Hence the fuel energy equation becomes, from (2.23),
Uf ea = Cpf (T3 − T2ea) kJ/kg (2.30)
Where
T2ea = T1(rp
βc − 1 + ηc)
ηc
(2.31)
Where rc and rt apply to the compressor and turbine and are found from Cpc, Cpt and Cv.
The work done on the generator is now,
Uoutea = Cpt T3(1 − rp
δt )ηt − CpcT1
ηc
(rp
βt − 1) (2.32)
and
T4ea = T3(ηt rp
δc + 1 − ηt )
From Uf ea and Uoutea the thermal efficiency ηpa can be found as,
ηpa = Uoutea
Uf ea
(2.33)

Gas Turbine Driven Generators

noreply@blogger.com (Jemsguns) — Wed, 23 Dec 2009 09:14:00 +0700

2.1 CLASSIFICATION OF GAS TURBINE ENGINES
For an individual generator that is rated above 1000 kW, and is to be used in the oil industry, it
is usual practice to use a gas turbine as the driving machine (also called the prime mover). Below
1000 kW a diesel engine is normally preferred, usually because it is an emergency generator running
on diesel oil fuel.
Gas turbines can be classified in several ways, common forms are:-
• Aero-derivative gas turbines.
• Light industrial gas turbines.
• Heavy industrial gas turbines.
2.1.1 Aero-derivative Gas Turbines
Aircraft engines are used as ‘gas generators’, i.e. as a source of hot, high velocity gas. This gas is
then directed into a power turbine, which is placed close up to the exhaust of the gas generator. The
power turbine drives the generator. The benefits of this arrangement are:-
• Easy maintenance since the gas generator can be removed as a single, simple module. This can be
achieved very quickly when compared with other systems.
• High power-to-weight ratio, which is very beneficial in an offshore situation.
• Can be easily designed for single lift modular installations.
• Easy to operate.
• They use the minimum of floor area.
The main disadvantages are:-
• Relatively high costs of maintenance due to short running times between overhauls.
• Fuel economy is usually lower than other types of gas turbines.
• The gas generators are expensive to replace.Aero-derivative generators are available in single unit form for power outputs from about
8 MW up to about 25 MW. These outputs fall conveniently into the typical power outputs required
in the oil and gas production industry, such as those on offshore platforms.
2.1.2 Light Industrial Gas Turbines
Some manufacturers utilize certain of the advantages of the aero-derivative machines, i.e. high powerto-
weight ratio and easy maintenance. The high power-to-weight ratios are achieved by running
the machines with high combustion and exhaust temperatures and by operating the primary air
compressors at reasonably high compression ratios i.e. above 7. A minimum of metal is used and so
a more frequent maintenance programme is needed. Easier maintenance is achieved by designing the
combustion chambers, the gas generator and compressor turbine section to be easily removable as a
single modular type of unit. The ratings of machines in this category are limited to about 10 MW.
2.1.3 Heavy Industrial Gas Turbines
Heavy industrial gas turbines are usually to be found in refineries, chemical plants and power utilities.
They are chosen mainly because of their long and reliable running times between major maintenance
overhauls. They are also capable of burning most types of liquid and gaseous fuel, even the heavier
crude oils. They also tend to tolerate a higher level of impurities in the fuels. Heavy industrial
machines are unsuitable for offshore applications because:-
• Their poor power-to-weight ratio means that the structures supporting them would need to be much
larger and stronger.
• Maintenance shutdown time is usually much longer and is inconvenient because the machine must
be disassembled into many separate components. A modular concept is not possible in the design
of these heavy industrial machines.
• The thermodynamic performance is usually poorer than that of the light and medium machines.
This is partly due to the need for low compression ratios in the compressor.
They do, however, lend themselves to various methods of heat energy recovery e.g. exhaust
heat exchangers, recuperators on the inlet air.
Figures 2.1 and 2.2 show the relative costs and weights for these types of machines.
2.1.4 Single and Two-shaft Gas Turbines
There are basically two gas turbine driving methods, known as ‘single-shaft’ and ‘two (or twin) shaft’
drives. In a single-shaft gas turbine, all the rotating elements share a common shaft. The common
elements are the air compressor, the compressor turbine and the power turbine. The power turbine
drives the generator.
In some gas turbines, the compressor turbine and the power turbine are an integral component.
This tends to be the case with heavy-duty machines.
The basic arrangement is shown in Figure 2.3.

Grounding Route

noreply@blogger.com (Jemsguns) — Tue, 22 Dec 2009 17:25:00 +0700

Kita harus membagi grounding menjadi beberapa tipe grounding, yaitu:
1. Signal Ground
Signal Ground harus berpusat pada Main Device (Controller, FF Host, DCS, PLC, dsb.), dimana Main Device dihubungkan ke Earth. Semua Field Device floating (shield drain wire tidak dihubungkan ke device itu sendiri - seperti dikatakan Pak Setyohadi dibawah), tetapi pada setiap junction box / marshalling semua shield drain wire harus tetap dihubungkan yang pada akhirnya drain wire akan terhubung ke Earth di Main Device.
2. Power Ground
Power Ground harus berpusat pada Power Generating Device, dimana Neutral dihubungkan ke Earth.
3. Body Ground
Panel / Enclosure body harus dihubungkan ke Earth terdekat (local) untuk melindungi personel yang bekerja disekitar panel / enclosure agar tidak terkena electric shock. Kalau kita menggunakan Surge Protector, ground juga harus dihubungkan ke local earth. Surge Protector adalah isolated dan baru membuang energinya pada ambang batas tegangan tertentu, dan device diproteksi dengan fuse.

Ketiga tipe ground tersebut harus isolated (tidak saling dihubungkan satu dengan yang lain), karena masing-masing mempunyai earth point sendiri. Menghubungkan satu atau lebih tipe ground diatas bisa menyebabkan ground loop karena akan terjadi multiple earthing. Sebagai standard (semua standard), panel / enclosure harus mempunyai 3 jenis ground bar, dimana Body Ground attached padapanel / enclosure body, sedangkan dua ground bar lainnya harus isolated.

Menjawab pertanyaan Mas Setyohadi, ketiga tipe ground tersebut harus dipisah / isolated satu terhadap yang lain (resistansi sebesar mungkin); Resistansi Earth sekecil mungkin. Memang agak membingungkan kalau kita bekerja di Power Generating Plant, seperti pengalaman saya di Pembangkit Kamojang, disitu hanya ada satu ground yang di-asumsi = earth, jadi ketiganya disatukan. Ukuran Ground cable juga harus diperhatikan current carrying capacity-nya agar tidak panas atau menjadi fuse; untuk signal ground, standard drain wire dari signal cable sudah cukup karena tujuannya adalah membuang potential dari EMI dan RFI; sedangkan untuk Power Ground dan Body Ground (terutama apabila menggunakan surge protector), kA rating harus diperhitungkan.

Sebagai tambahan:
Khusus untuk signal dengan frekwensi tinggi - orde MHz ~ GHz, seperti Ethernet 100/1000BaseTx (copper screened/shielded twisted pair), grounding diperlakukan secara khusus. Kalau pada butir 1 diatas (low frequency) field end harus floating, pada frequency tinggi setiap ujung shield/screen harus grounded, karena pada frequency tinggi shield/screen menjadi semacam antenna dan akan timbul standing wave. Umumnya high frequency signal cable jaraknya tidak terlampau panjang, sehingga kita bisa memasang grounding grid (anyaman bujur sangkar) yang dihubungkan ke Earth. Semua screen/shield di-ground ke Grounding Grid tersebut.

Working Effectively and Safely in an Electrical Environment

noreply@blogger.com (Jemsguns) — Mon, 9 Nov 2009 09:16:00 +0700

When the electrical team arrives on site to, let us say,
‘first fix’ a new domestic dwelling house, the downstairs
floorboards and the ceiling plasterboards will
probably not be in place, and the person putting in
the power cables for the downstairs sockets will need
to step over the floor joists, or walk and kneel on
planks temporarily laid over the floor joists.
The electrical team spend a lot of time on their hands
and knees in confined spaces, on ladders, scaffold
towers and on temporary safety systems during the
‘first fix’ of the process and, as a consequence, slips,
trips and falls do occur.
To make all working environments safer, laws and

safety regulations have been introduced. To make yourworking environment safe for yourself and those
around you, you must obey all the safety regulations
that are relevant to your work.
The many laws and regulations controlling the working
environment have one common purpose, to make
the working environment safe for everyone.
Let us now look at some of these laws and regulations
as they apply to the Electrotechnical Industry.

Statutory Laws
Acts of Parliament are made up of Statutes. Statutory
Laws and Regulations have been passed by Parliament
and have therefore become laws. The City and Guilds
Syllabus requires that we look at seven Statutory
Regulations.
1. The Health & Safety at Work Act 1974
◆ The purpose of the HSAWA is to provide the legal
framework for stimulating and encouraging high
standards of health and safety at work.
◆ The Act places the responsibility for safety at
work on both workers and employers.
◆ The HSAWA is an “Enabling Act” which allows the
Secretary of State to make further regulations
and modify existing regulations to create a safe
working environment without the need to pass
another Act of Parliament.

2. Electricity at Work Regulations 1989
◆ These Regulations are made under the Health &
Safety at Work Act and are enforced by the
Health & Safety Executive (HSE).
◆ The purpose of the Regulations is to “require
precautions to be taken against the risk of death or
personal injury from electricity in work activities”.
◆ An electrical installation wired in accordance
with the IEE Regulations BS 7671 will also meet
the requirements of the EWR.
3. The Electricity Safety, Quality and
Continuity Regulations 2002
◆ These Regulations are designed to ensure a
proper and safe supply of electrical energy up to
the consumer’s mains electrical intake position.
◆ They will not normally concern the electrical
contractor, except in that it is these Regulations
which set out the earthing requirements of the
supply.
4. The Management of Health & Safety at
Work Regulations 1999
◆ To comply with the Health & Safety at Work Act
1974 employers must have “robust health and
safety systems and procedures in the workplace”.
◆ Employers must “systematically examine
the workplace, the work activity and the
management of safety through a process of
risk assessment”.

◆ Information based upon the risk assessment
findings must be communicated to relevant staff.
◆ So, risk assessment must form a part of any
employer’s “robust policy of health and safety”.
5. Provision and Use of Work Equipment
Regulations 1998
◆ These Regulations place a general duty of care
upon employers to ensure minimum requirements
of plant and equipment used in work activities.
◆ If an employer has purchased good quality plant
and equipment, and that plant and equipment is
well maintained, there is little else to do.
6. COSHH Regulations (2002)
◆ The Control of Substances Hazardous to Health
Regulations (COSHH) control people’s exposure
to hazardous substances in the workplace.
◆ Employers must carry out risk assessments
and, where necessary, provide PPE (Personal
Protective Equipment) so that employees will
not endanger themselves.
◆ Employees must also receive information and
training in the safe storage, disposal and
emergency procedures which are to be followed
by anyone using hazardous substances.
7. Personal Protective Equipment Regulations (PPE)
◆ PPE is defined as all equipment designed to be
worn or held in order to protect against a risk to
health and safety.

◆ This includes most types of protective clothing
and equipment such as eye, foot and head
protection, safety harnesses, life jackets and
high visibility clothing.
◆ Employers must provide PPE free of charge and
employees must make use of it for their
protection.
◆ Figure 1.1 below shows the type of safety signs
which might be used to indicate the type of PPE
to be worn in particular circumstances for your
protection.
Working Effectively and Safely in an Electrical Environment 7
Have