AFTER THIS SESSION WE WILL GET A GUIDELINE ON ESA:
 How We will work in the filed
 Which areas come first in the findings list
 How we will decide an issue is either High, Medium or
Low risky
 How we correlate the issues with regulations
An easy going activities of performing assessment in the
factories
Clarification of ambiguous issues striking in your heads
 Well Documentation (though we experienced already)
 Personal Safety issues at work places
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Page 2
THE TYPICAL ESA SCOPE OF WORK COULD INCLUDE
 Physical inspection to identify electrical hazards (shock, fire,
explosion, overloading) and to suggest electrical safety solutions
 Review of static electricity hazards in the plant operations (if
applicable)
 Review of hazardous area classification and selection of flameproof
electrical equipment in the plant, including maintenance aspects (if
applicable)
 Review of electrical preventive maintenance system (including tests,
documentation, history cards, etc.)
 Review of electrical accidents and near misses in the plant to identify
the root causes
 Review of electrical systems & procedures (work permits, interlocks,
lockout & tagout practice, etc.)
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THE TYPICAL ESA SCOPE OF WORK COULD INCLUDE………CONT.
 Review of the importance given to electrical safety in the company
safety policy, safety committee, continuous electrical risk
identification, etc.
 Assessing the integrity of insulation of cables by carrying out
insulation resistance tests on a sample basis
 Review of plant lightning protection system (need, adequacy,
installation and Maintenance)
 Review of the earthing system (installation & maintenance aspects),
including sample earth resistance tests
 To identify areas of overloading by carrying out load current
measurements and compared against cable current carrying capacity
calculation
 Hotspot detection using infra‐red hot spot detection equipment/
thermal imaging (as necessary)
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4
ELECCTRICAL SYSTEM VOLTAGE LEVEL
Level
Range
Extra Low Voltage
<50 V
Low Voltage
50 V ~ 600 V
Medium Voltage
601 V ~ 69 KV
High Voltage
69 KV ~ 230 KV
Extra High Voltage
230 KV ~ 800 KV
Ultra High Voltage
>800 KV
So, we are working in the range of Low Voltage range and need sufficient
protection for individual and overall safety.
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ELECTRICAL ACCIDENTS
Leading Causes of Electrical Accidents:










Drilling and cutting through cables
Using defective tools, cables and equipment
Failure to maintain clearance distance of 10 feet
Failure to de-energize circuits and follow Lockout/Tagout
procedures
Failure to guard live parts from accidental worker contact
Unqualified employees working with electricity
Improper installation/use of temporary electrical systems
and equipment
By-passing electrical protective devices
Not using GFCI (ground fault circuit interrupters) devices
Missing ground prongs on extension cords
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ELECTRICAL HAZARDS
Classification and Identify Electrical Hazards in the workplace is
important and the Hazards are commonly four types
 SHOCK/EXTROCUTION,
 FIRE/ARC FLASH,
 EXPLOSION/ARC BLAST and
 OVERLOADING
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7
HAZARD RECOGNITIONS
 Cords & Equipment
 Electrical Panels
 Trip Hazards
 Exposed Wiring
 Power Strips
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EFFECTS OF ELECTRICITY ON THE HUMAN BODY
 The four major types of electrical injuries are:
 Direct
Electrocution
Electrical Shock
Burns
 Indirect
Falls
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EFFECTS OF ELECTRICITY ON THE HUMAN BODY…….CONT.
Injuries Depend on:
Current and Voltage
Resistance
Path through body
Duration of shock






More than 3 mA- Painful shock- cause indirect accident
More than 10 mA- Muscle contraction – “No Let Go” danger
More than 30 mA- Lung paralysis, usually temporary
More than 50 mA- Ventricular fibrillation, usually fatal
100 mA to 4 A- Certain ventricular fibrillation, fatal
Over 4 A- Heart paralysis, severe burns
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ELECTRICAL HAZARD PROTECTIONS
 Insulation (Proper type material use; mostly cable insulation)
 Grounding (Earthing connection for all electrical equipment)
 Guarding (panels or distribution boxes)
 Electrical Protective Devices (RCBO), GFCI, RCD, MCB)
 Personal Protective Equipment (Gloves, Cotton garment etc)
 Safe work practices (following regulations local and internationals
like BNBC, IEE onsite regulations (17th Ed. BS 7671:2008), NEC
2008, NFPA 70E, IEC 60364)
RCBO
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GFCI
RCD
IEE
NEC
NFPA
IEC
Residual Current Circuit Breaker with
integrated Overcurrent protection
Ground Fault Circuit Interrupter
Residual Current Device
Institute of Electrical Engineers
National Electric Code (for USA)
National Fire Protection Association
International Electrotechnical Commission
Page 11
INSULATION & ELECTRICAL PROTECTIVE DEVICES
To reduce the electrical hazards in the workplace well insulated cables have no
alternate and to be safer or even safest, electric protective devices are
necessary.
Bad insulation in low voltage system causes leakage current from the conducting
cable and eventually hazards occurs and in some extreme cases fire generates.
How we can protect it or test it?
If we use RCCB, GFCI or RCD we can sense leakage current in the system.
If we don’t install any RCCB, GFCI or RCD we can test the cable to sense the
leakage current; but we need high sensitive measuring tools.
By measuring cable insulation we can be sure about the insulation status of a
cable.
So, if we recommend a customer to install RCD/GFCI/RCCB cable
insulation will be ensured at the same time.
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GROUNDING/EARTHING CONNECTION
 Grounding or Earthing connection is very crucial to make a system safe. In
industries the following type earthing system are used:
1.
2.
3.
4.
5.
6.
TT system
TN System
TN-C System
TN-S System
TN-C-S System
IT System
 The first letter indicates the relationship of the power system to earth:
– T = direct connection to earth of one point, usually the neutral, in a.c. systems;
– I = all live parts isolated from earth or one point, usually the neutral, connected
to earth through an impedance
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GROUNDING/EARTHING CONNECTION…….CONT.
 The second letter indicates the relationship of the exposed conductors of the
installation to earth:
– T = direct electrical connection of exposed conductors to earth;
– N = direct electrical connection of the exposed conductors to the earthing point
of the power system.
 Subsequent letters, if any, indicate the arrangement of neutral and protective
conductors:
– S = neutral and protective functions provided by separate conductors
– C = neutral and protective functions combined in a single conductor (PEN
conductor).
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GROUNDING/EARTHING CONNECTIONs…….CONT.
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15
ELECTRICAL PROTECTIVE DEVICES
The proper selection of the correct circuit protective device requires an
understanding of the potential hazards against which protection for safety is
required.
There are lot of faults in the electrical system that are needed to be protected as
soon as possible, like
1. Overcurrent Protection
2. Short Circuit Current Protection
3. Under voltage Protection
4. Leakage Current Protection
5. Overload Protection
6. Open Circuit Fault Protection
these two are found in motor generators
7. Interturn Fault Protection
and transformers
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ELECTRICAL PROTECTIVE DEVICES………CONT.
To calculate or measure the faults (related to protective devices) and to
understand the labels on some protective devices we must have a clear idea on
some terms, like:
Ia
U0
Current causing automatic disconnection within the required time = ICU
Zs
Ip
Earth Fault Loop Impedance
Prospective Earth fault Current
Earth Fault Loop Impedance
(R1 +R2) R1 is the resistance of the phase conductor within the installation and R2 is the
resistance of the circuit protective conductor (Some cases called as RA)
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ELECTRICAL PROTECTIVE DEVICES………CONT.
Residual Current Device (RCD) :
RCD (in EU), GFCI (in UK) is a very important protection device for leakage
current or any ground fault. Earlier RCCB or RCBO were used do the same job;
but in modern technology they are replaced by RCD. According to BS 7671:2008
it is mandatory to use RCD even at the 20A socket in the industries. It is
strongly prohibited not to use RCD in TN-C system.
For Using RCD we need to know RA, Zs, Ia, Ip, In, U0, breaker type (A/B/C/D).
Rule of thumb: Zs <= 0.8 * U0 / Ia
For calculating Ip : generic calculation is divide by simply
divide the applied voltage (U0) by the earth fault loop
impedance (Zs) at the point in question and there you have it –
prospective earth fault current, Ip .
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ELECTRICAL PROTECTIVE DEVICES………CONT.
 Calculating Fault Loop Impedance and Circuit Breaker sizing
The calculations you need to do for a circuit are not difficult. There are tables for
every cable manufacturer that give you the resistance of cables of different
sizes.
 Example:
4mm2 copper wire has a resistance of 0.0046 ohms per metre.
If circular cable was used the earth wire would be 2.5mm2,
which has a resistance of 0.074 ohms per metre. The cable
run is 100m.
Total resistance = Resistance of Active + Resistance of
Earth
= (100 x 0.0046) + (100 x 0.0074)
= 0.46 + 0.74
= 1.202 ohms
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ELECTRICAL PROTECTIVE DEVICES………CONT.
 Example:
The cable run in the example above is going to be used to run a 7.5kW motor which will draw
14A. It is going to be DOL and so will require a 40A circuit breaker to start.
On the surface this circuit appears to be fine. The voltage drop
will be 14A x 0.741 ohms = 10.3V, which is less than the maximum
12V drop allowed. The earth resistance is less than 0.5ohms, which
is the maximum earth impedance stated in (unanimous manufacturer
cable chart). The maximum current that 4mm2can take (touching) is
29A - which is way above the 14A load.
However, the short circuit current is a different matter. The
current that would flow in a short circuit can be calculated as
follows:
I = V / R
= 240 / 1.202
= 199A
The circuit breaker will trip in an adequate time when there is
more than 7.5 times its rated current flowing through it. In this
case:
Trip current = 40A x 7.5 = 300A
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ELECTRICAL ARC FLASH/FIRE
An arc flash is an unexpected sudden release of heat and light energy produced
by electricity travelling through air, usually caused by accidental contact between
live conductors. Temperature at the arc terminal can reach or exceed 35,000ºF.
An arc flash is a short circuit through air in an electric panel box or any other
piece of energized electrical equipment. A short circuit will have almost zero
resistance and will have very high levels of current. The high current is what is
responsible for the arc flash.
 An accidental slip of tool, a loose part, or even body touching live parts can
provide the start the current needs to jump from one cable to another
 Loose connections n the electrical equipment, improper installation, and parts
that break and fall ate other possible trigger.
 Dust, water, impurities, contamination, corrosion, oil and grease can also
provide a starting route for the short circuit.
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ELECTRICAL ARC FLASH/FIRE……….CONT.
 Even animals or
bugs can get into
electrical
devices
and produce arc
flash.
 Typically there is
always a reason for
arc flash accidents,
although we ay not
always know what it
was.
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22
Equipment
Flash Protection Boundary (FPB)
Must wear appropriate PPE
FPB dependent on fault level and time
duration.
Prohibited shock boundary:
Qualified persons only - PPE as if direct
contact with live part
Restricted shock boundary:
Qualified persons only
Limited shock boundary:
Qualified or unqualified persons*
*only if accompanied by qualified person
Note: shock boundaries dependent on system voltage level
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23
ELECTRICAL ARC BLAST/EXPLOSION
During an Arc Flash, the rapidly expanding gases and heated air may cause
blasts, pressure waves, o explosions. The gases expelled from the blast also
carry the products of the arc with them including droplets of molten metal. Even
large objects such as switchboard doors, bus bars, or other components can
be propelled several feet at extremely high velocity. Arc Blast pressure may
exceed 2000 lb/square foot, knocking workers of ladders or collapsing
workers’ lugs. These events occur very rapidly with speeds exceeding 700
miles/hour making it impossible for a workers to get out of the way. The
intense light generated by the arc flash emits dangerous UV frequencies, which
may cause temporary or permanent blindness. The sound energy from blast
and pressure waves can reach up to 160 dB.
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24
REVIEW OF ELECTRICAL PREVENTIVE MAINTENANCE SYSTEM
According to BS 7671: 2008 and BNBC 2010 maintaining for electrical systems
preventive maintenance checklist/logbook is necessary.
 During audit/assessment ask concern people for generator, transformer
preventive maintenance logbook.
 For Generator usually you can see AMC between supplier and customer. If
you observed AMC, then just ask for the supplier’s preventive maintenance
checklist/logbook and review it. If not, then it will be our scope of work.
 If the transformer is govt. owned, then ask for the test report (if it is old
enough that is supposed to perform some test) provided by the power
supplier (DPDC/DESCO/REB/PDB)
 If the transformer is customer’s property, then note history- the date of
purchase; if it is new, then don’t ask for any test document; otherwise ask the
same documents as mentioned above.
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25
REVIEW OF ELECTRICAL PREVENTIVE MAINTENANCE SYSTEM
 Review the preventive maintenance logbook for MDBs, DBs and SDBs
 Review emergency power supplier (usually DG) preventive maintenance
check book.
 If the customer has large sized battery bank, then ask for the battery bank
maintenance log book/check list.
 If the maintain any history card for all the maintenance issues, just have a
review and note
 Ask for test certificates if they use any protective devices in the electrical
system.
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26
REVIEW OF ELECTRICAL ACCIDENTS AND NEAR MISSES
Near Miss Accident means any unplanned, sudden event that could have caused
injury to man, materials (plant) or environment or could have involved a loss of
containment possibly giving rise to adverse effect but not resulted in such
accident.
And if any one becomes a victim of that sudden event we call it as Accident.
Accident and Near Misses Accidents tell you what electrical cultures are really
maintained in the factory . So, to get a better idea on the plant’s electrical system
and the awareness of the people this record is helpful.
So, ask for the record and review it.
How do you get this information if the customer don’t have record?
Become friendly with the worker and ask them; if they rely on you, they will
certainly tell you if they had any history like this.
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REVIEW OF ELECTRICAL ACCIDENTS AND NEAR MISSES…….CONT.
Example:
Accident:
A woman was putting up her Christmas tree. When she went to plug in the
strands of lights, her finger was touching the metal prong on the plug. Her other
hand was touching a metal coffee table leg for support. The current went through
her body as a result, causing cardiac arrest and death.
Or
A man was working in a live system and during wire stripping he shorten phase
and neutral and get burn in first degree.
Near Miss Accident:
A worker came out of the bathroom with her hands dripping wet, and reached
down to plug in a lamp. She got a shock but survived.
Or
A rat has found dead due to leakage current at distributor cable trench.
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ELECTRICAL SYSTEMS & PROCEDURES
OSHA 1910:333 (b) and IEE (BS 7671: 2008 chapter 53) NEC 2008 and BNBC
2010 all regulations say about the Lock out & Tag out or Interlocking system
while working on energized system.

Lockout/ tag out indicates:
I.
II.
III.
IV.

De-energizing equipment
Application of locks and tags
Verification of de-energized condition
Reenergizing equipment after work
Interlocking indicates:
This is another way of lock out and tag out culture

Work Permit :
Only the authorized person will do the lock out /tag out jobs during
preventive or break down maintenance. For doing this job safety authority
combined with electrical department will issue a work permit to perform this job.
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29
ELECTRICAL SYSTEMS & PROCEDURES………CONT.
We are well known that most of the factory do not practice this type of culture on
electrical system. In RMG sector electrical systems are run by poor academic
qualified personnel who doesn’t have such level of awareness. So, while roaming
in the factory collect information on this type of practice.
In some factories you might have found some practice of logout or tag out; but
these are not acceptable.
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30
LIGHTNING ARRESTER AND EARTHING SYSTEM
To keep safe any building from lightning a lightning arrester is necessary to install
on the top of a building. According BNBC 2010 (part 8 chapter 1), BS 7671:2008
(Chapter 54) it is mandatory to install Lightning arrester for a building.
In the factory we will review on the lightning arrester system and note the
findings;
Now,
 Does every building need to install Lightning arrester?
 Does any part of the roof top Ok for installing LA?
 Does one LA ok for any type/size of building?
 Does any Earth leading cable is ok for Earth leading conductor?
 Earth leading conductor latches with other power cable, is it acceptable?
 What is the height of LA’s air spike?
 Is it acceptable if you found Earth leading conductor of LA has ended at
common earthing bar?
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31
LIGHTNING ARRESTER AND EARTHING SYSTEM……..CONT.
In our previous slides we have mentioned about different types of Earthing
connection systems. In RMG sectors in Bangladesh you will find a different type
earthing connection for the electrical appliances. You can define it as TT-TN-C-S
(its not an standard; just for your understanding). So, this type of earthing
arrangement is not acceptable. It must be either TT or TN-C or TN-S or TN-C-S.
So, have a detail review on the earthing system of the factory; then come to a
decision which type of earthing system is prominent of that particular factory.
After that start measuring of Earth Resistance, Earth Continuity Resistance.
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32
LIGHTNING ARRESTER AND EARTHING SYSTEM……..CONT.
According to BNBC 2010
1.3.47.7.1
Earth resistance tests shall be made on the system, separating and reconnecting
each earth connection using earth resistance meter.
1.3.47.7.2
The electrical resistance of the Earth Continuity Conductor of different segmen
t shall be measured separately using sensitive digital Ohm meter or by means o
f resistance bridge instrument. The resistance of the Earth Lead Wire shall be me
asured from the Earthing Busbar of the LT Panel / MDB /DB and the Earth Electr
ode(s). The electrical resistance of any section shall not exceed 1 ohm.
1.3.47.7.3
Where more than one earthing sets are installed, the earth resistance between t
wo sets shall be measured by means of sensitive digital Ohm meter or by means
of resistance bridge instrument. The earth resistance between two sets shall not
exceed 1 ohm.
For more detail go through BNBC 2010 Part 8,
article 1.3.47.8 Inspection of the Installation
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33
IDENTIFY AREAS OF OVERLOADING BY CARRYING OUT LOAD
CURRENT MEASUREMENTS AND COMPARED
AGAINST CABLE CURRENT CARRYING CAPACITY CALCULATION
A factory’s main circuit breaker/ LT panel will say the loading capacity of that
factory as well as the power quality, harmonics, THD, power factor and so on.
The incoming cable from the generation/Substations says the cable loading
capacity for the specific portion.
If we take all the MCBs rating and temperature, and the incoming power cable to
the MCB we can summarize the Circuit Breakers’ loading capacity and also the
loading capacity of the incoming power cables. From these data we can prepare
a table for that particular factory. (example will be given at later)
What is the reason behind connecting Power logger at every circuit in the
electrical system whereas we have a thermography report on that system?
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34
EXAMPLE OF CABLE LOADING CAPACITY CHART
Cable location
Cable Size
(RM)
Rated Capacity
(in Air @35°C)
Measured
Current
(A)
(A)
Loading
Percentage (%)
Temperature
(°C)
Remarks
Main incoming
to MDB
240
555
445
80.2
47
Under sized cable is
used; future expansion is
not possible
Bus bar to
distributed
MCCB (in MDB)
240
555
225
40.5
41
OK
MDB bus bar to
First Floor DB 1
70
245
66
26.9
39
OK
MDB bus bar to
First Floor DB 2
70
245
49
20.0
38
OK
70
245
79
32.2
42
OK
70
245
60
24.5
41
OK
MDB bus bar to
Third Floor
70
245
73
29.8
37
OK
MDB bus bar to
Forth Floor
70
245
92
37.6
87
thermo graphic report is
attached
MDB bus bar to
Second Floor DB
1
MDB bus bar to
Second Floor DB
2
Average Loading
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36.46 %
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35
EXAMPLE OF BREAKER LOADING CAPACITY CHART
Rated
Capacity
MCCB
location
(A)
Measured
Current (A)
Loading
Percentage
(%)
Temperature
(°C)
Cable
Size(incoming,
Outgoing)
Remarks
(RM)
Over sized MCCB
used; for future
expansion
Over sized MCCB
used; for future
expansion
MDB Main
MCCB
800
445
56
43
240, 300
MDB Isolated
MCCB
630
225
36
41
185, 240
250
66
26
39
70, 70
Over sized
175
49
28
38
70, 70
Over sized
250
79
31
42
95, 70
Over sized
200
60
30
41
70, 70
Over sized
250
73
29
37
70, 70
Over sized
70, 70
Over sized and
thermo graphic
report is attached
First Floor DB
1
First Floor DB
2
Second Floor
DB 1
Second Floor
DB 2
Third Floor
Forth Floor
200
Average Loading
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92
46
87
35.25 %
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36
IDENTIFY AREAS OF OVERLOADING BY CARRYING OUT LOAD
CURRENT MEASUREMENTS AND COMPARED
AGAINST CABLE CURRENT CARRYING CAPACITY
CALCULATION…….CONT
During assessment check the following documents they have:
1.
2.
3.
4.
Cable current carrying capacity chart
All the Cable schedules
All the Breakers specifications
Cables size and the RCD types and technical specifications
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37
FIRE PROTECTION SYSTEM
Electricity does not create fire; but it causes fire. So, Fire safety and protection
will be partially covered under Electrical Safety Audit/Assessment. So, these
following issues must be checked while we are moving around a factory for ESA.
1. Adequacy of Fire Extinguishers
2. Inflammable material near the Electrical Panels/Sub-Station & generator room
3. Working condition of Fire Extinguishers
4. Awareness of Occupants on location of Fire extinguishers
5. Awareness of Occupants on operation of Fire extinguishers
6. Suitability of Fire extinguishers to Specific requirements
7. Adequacy of Fire alarming system
8. Power supply to Fire detection & protection system
9. Operation of Fire extinguishing system
10. Adequacy of Fire hydrant system
11. Preventive maintenance checklist of Fire hydrant system
12. Fire Drill Activities
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PERSONAL PROTECTION EQUIPMENT
1. Presence of Personal Protection Equipments (PPE) in required areas
2. Culture of using PPE at workplace of the Electrical personnel
3. Presence of Insulated Rubber mat near the working areas of electrical
systems
4. Adequate knowledge of the electrical personnel of using right PPE to
the right electrical areas
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39
ELECTRICAL SAFETY ASSESSMENT/AUDIT
What is Safety Audit?
Safety Audit is a systematic approach to evaluate potential hazards and to
recommend suggestions for improvement. SA is an important tool for identifying
deteriorations of standard, areas of risks or vulnerability, hazards and potential
accidents in plants for determining necessary action to / minimize hazards and for
ensuring that the whole safety effort is effective & meaningful.
Safety Audits are carried out due to various reasons such as:
1. Statutory requirement (environmental concerns, Risk Analysis for hazards
industries, etc.)
2. Requirement of financial institution (for loans, etc.)
3. Suggestion of an regulatory authorities
4. Process change /plant capacity addition
5. Change of management (Merger / Acquisition)
6. Genuine management concern as a measure of improvement
7. Part of OH&S (Occupational Health & Safety) policy of the organization
8. Major accident in the plant / major accident in the neighboring industry /major
accident in a similar industry
9. Requirement of foreign partner
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40
ELECTRICAL SAFETY ASSESSMENT/AUDIT…….CONT.
ELECTRICAL SAFETY AUDIT PROGRAM
Electrical Safety Audit program can be broadly classified into three major areas
namely:
1. Pre-Electrical Safety Audit Elements
2. Electrical Safety Auditing
3. Post Electrical Safety Audit Elements
Pre-Electrical Safety Audit Elements
1. ESA scope of works
2. ESA Team compositions
3. Pre-Electrical Safety Audit Questionnaire
4. Audit Preparation
5. Pre-Audit/Assessment meeting
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41
ELECTRICAL SAFETY ASSESSMENT/AUDIT…….CONT.
Electrical Safety Auditing
1. Field Visit
2. Discussion with Safety Electrical Personnel
3. Review of Documents / Records
Post - Electrical Safety Audit
1. Electrical Safety Audit Report Format
2. Electrical Safety Audit Report format
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Executive Summary
Introduction
Specific Observation and Recommendations
Review of Electrical Test records and Test Procedures
Annexure (for reference, guidelines, etc.)
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ELECTRICAL SAFETY ASSESSMENT/AUDIT…….CONT.
We are very much experienced in Auditing; so, we better move to scope of work.
In previous slides we have already mentioned the scope of work and in short again
we mention here:
1. Identification of Electrical Hazards
2. Review of protection devices & systems of the electrical installation
3. Review of major cables on sampling basis capacity and sizing
4. Survey of factory lightning Protection System if applicable
5. Survey of Earthing System (Maintenance Aspect)
6. Review of Electrical Preventive maintenance program through document review
7. Examination of hand tools and PPE being used by the factory employees
8. Identification of Hot Spot at Electrical Panels by the state of the thermal imager
9. Review of system handling electrical accidents in the factory
10. Review of awareness among factory employees towards Electrical Safety
11. To check the compliance against legal & statutory requirement as per BNBC and
BS standards
12. Identification of gaps and gap analysis
13. Recommendation on mitigation of identified gaps
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ELECTRICAL SAFETY ASSESSMENT/AUDIT…….CONT.
BNBC Regulations on Electrical Installations
 1.3.9.1
General
Loads are separated into known and unknown loads.
 1.3.9.2
Distribution Board
 1.3.9.3
Circuit Wiring
 1.3.9.3.1
Separate branch circuits for separate control
 1.3.9.3.6
Separate branch circuits from miniature circuit breaker
Separate branch circuit shall be provided from Miniature Circuit
Breaker (MCB) of a BDB/SDB or fuse of the fuse distribution
boards (FDB) for light/fan.
 1.3.9.3.7
Less than 50% loading of circuits with more than one
outlet
Circuit with more than one outlet shall not be loaded in excess
of 50% of their current carrying capacity
 1.3.9.3.9
One spare circuit must be allowed in the distribution board
for each five circuits in use
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ELECTRICAL SAFETY ASSESSMENT/AUDIT…….CONT.
 1.3.9.3.14
 1.3.9.3.15
 1.3.9.3.16
 1.3.10
 1.3.10.2
 1.3.10.3
 1.3.10.7
 1.3.11.7
 1.3.13
 1.3.14.2.2
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Use of common neutral for more than one circuit is
prohibited
Following Correct color codes of cables
Balancing of circuits in three phase SDBs, DBs, FDBs, and
MDBs
Electrical Layout and Installation Drawings
Light and Fan circuits must not be mixed with the socket
circuits
Balancing of circuits in there phase Distribution Boxes is a
must
Preparation of electrical Distribution and Wiring Design
drawing by an expert Engineer
Cable joints and cable joint boxes in concealed and
surface wiring
Feeder Wiring between SDB and BDB, DB and SDB, FDB
to DB, MDB to FDB etc.
Phase and neutral cables shall be of the same size
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ELECTRICAL SAFETY ASSESSMENT/AUDIT…….CONT.
 1.3.19.7
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1.3.20
1.3.31.2
1.3.34
1.3.35
1.3.36
1.3.37.3.5
1.3.37.3.6
1.3.38
1.3.42
1.3.47.2
1.3.47.4
1.3.47.7
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Fire alarm and emergency lighting circuit shall be
segregated from all other cables and from each other in
accordance with BS 5839 and BS 5266
Design for Electrical Wiring
Circuit Breakers on Each Live Conductor
Location of Distribution Boards
Over current and Short Circuit Protection of Circuits
Fire alarm and emergency lighting circuits
Earthing Bus bars
Earthing Pit
Lightning Protection of Buildings
Fire Detection and Alarm System inside a Building
Periodic inspection and testing
Inspection of the color identification of cables of wiring
Earth Resistance Test and the Continuity Resistance Test
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ELECTRICAL SAFETY ASSESSMENT/AUDIT…….CONT.
REPORT PREPARATIONS:
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PPE and Auxiliaries for the Engineers
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Cotton work wear
Safety gloves for Low Voltage
Earplugs
Goggles
Safety Shoes
Torch light
Musk (optional)
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References
1.
2.
3.
4.
5.
6.
7.
8.
9.
10.
11.
12.
13.
14.
15.
16.
17.
18.
19.
20.
BNBC 2010, Part 8, Chapter 1
IEE on site wiring regulation (17th Edition) BS 7671:2008
National Electric Code (NEC) 2008
International Elecctrotechnical Commission (IEC), DIN 60364
NPFA 70E
OSHA 1910:302-399
http://www.industry.usa.siemens.com/services/us/en/industry-services/training/self-study-courses/safety-trainingseries/Pages/safety-training-series.aspx#Online%20Interactive%20Training
http://www.siemens.co.uk/traffic/pool/downloads/handbooks/road_signals/667_he_20664_000.pdf
http://www.sma.de/fileadmin/content/global/Solutions/Documents/Medium_Power_Solutions/RCD-UEN110430.pdf
http://www.tlc-direct.co.uk/Book/5.3.4.htm
http://www.mech.hku.hk/bse/mech3005/Circuit_Protection_Principle.pdf
http://www.tlc-direct.co.uk/Book/8.6.2.htm
http://www.theiet.org/forums/forum/messageview.cfm?catid=205&threadid=23069
http://www.electriciansforums.co.uk/electrical-wiring-theories-electrical-regulations/28677-selv-pelv-felv.html
http://forums.mikeholt.com/showthread.php?t=104643
http://kiran111.hubpages.com/hub/Electrical-Faults-on-Power-System
http://www.elek.com.au/Files/Understanding%20Earth%20Fault%20Loop%20Impedance.pdf
http://mandrelectrical.com.au/faultloopimpedance.php
http://www.abb.com/RCD
http://www.lbl.gov/ehs/pub3000/pub3000c.html
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