1.0 Introduction:

Electrical hazards continue to threaten safety of people in the form of shocks, burns, injury, fire and explosion besides loss of property. With electricity having become an indispensable part of our life, electrical risks are to be managed effectively. The importance of giving highest priority on electrical safety is nevertheless understood by the noble saying that “Electricity is a good slave but a bad master”.

One of the important pre-requisite of safe management of electricity is to ensure that the electrical installations are installed and maintained as per the mandated by various governing regulatory Acts and Codes besides the recommended safe engineering practices. The other requisite is to ensure part that electrically operated gadgets, devices and equipment are connected and used in a manner they are meant for.

M/s. UCO Bank had desired to have an electrical safety audit carried out at its zonal office in Chennai. Accordingly it had invited Tebodin Consultants & Engineers India Pvt Ltd., (hereinafter referred to as TIN) to conduct the electrical safety audit.

In terms of the work order No. ZO/GAD/SEC/94/2014-15 dated 10/01/2015 placed by M/s. UCO Bank, TIN had carried out the electrical safety audit of the Zonal office of m/s. UCO bank at Chennai.

This report narrates in brief the electrical safety audit plan, the observations made at site during the time of electrical safety audit, the measurements that were carried at site during the conduct of the safety audit and finally the recommendations for addressing those safety issues.

2.0 Brief Details of audit

Name and Address of the building that was subjected to electrical safety audit

Date(s) on which the electrical safety audit was conducted

Name and Designation of the person(s) who had represented UCO bank during the audit schedules

Name of the TIN auditees who had carried out the electrical safety audit

M/s. UCO BANK, Ramesh Narayanan,

ZONAL OFFICE, No.328, Thambu Chetty Street, Chennai – 600 001, India

14th Jan 2015 and

Mr.Rama Mahendra Rao, Chief Safety Officer

Project Manager & Lead Auditor

Anandan E, Lead Auditor

Sridharan L, Auditor

Auditing support staff – 3 Members ( Lux level measurement, Electrician & Helper )

3.0 Methodology of conduct of Electrical Safety Audit

The audit plan was structured in the following manner

Pre- audit phase

o Pre-Audit Coordination Meetingo Audit plan

Audit Phase

o Physical Inspection o Conducting Test and Measuremento Discussion with Safety & Electrical personnelo Examination & Review of Records/ Document

Post Audit Phase

o Electrical Safety Audit Report Submissiono Review Meeting with Management

Pre-audit co-ordination meeting

Prior to the commencement of electrical safety audit, a brief meeting was held with the concerned officials of m/s. UCO bank to understand more details about the premises at which the audit was scheduled and

to ascertain the “as built” and “as is where is” information about the electrical infrastructures / installations available in that premises.

Brief Details about the building, the existing electrical infrastructure and facilities in this building.

The Zonal Office building is a six storied building comprising of the following

Floor Brief Description of the usage of the floorGround Floor Main Electrical Switch room, Transformer

Room, Panel room and lift lobbyFirst Floor Cash room, record room and bank operationsSecond Floor Zonal manager’s cabin, credit and recovery

departmentsThird Floor UPS room, Office areaFourth Floor Retail Loan section, computer centre,, general

officeFifth floor Trainees hostel, dining hall, doctor’s roomSixth floor RTC Principal’s cabin, class room, conference

room, faculty room

Brief details of the existing electrical infrastructure

Incoming power supply from EB 11 kVHT service connection No. 2072Installed capacity of Transformer 1 x 500 kVA, 11/0.415 kV, Oil filled

typeType of HT breaker RMU with Oil switch in incoming and

outgoing side and Oil circuit breaker in the Tee off

Date of installation of HT panel 09/12/1970Installed capacity of DG set 1 x 250 kVA with acoustic enclosure

Audit phase

Audit Objectives

The key focus of the electrical safety audit were as below:-

Assessment of electrical panel room Assessment of Earthing system

Assessment of Diesel Generating Set Assessment of electric circuit Assessment of lighting protection system Assessment of Air conditioning system Assessment of UPS Assessment of Pump Assessment of luminaries/ light fittings

The audit team was equipped with the following instruments

Clip on type tong tester Earth Megger Insulation Megger Lux Meter Decibel Meter Necessary PPE

Based on the details collected during the pre-audit meeting, the available electrical system was studied in depth and key nodes were identified for the purpose of carrying out measurements of electrical parameters.

Audit findings in brief

Assessment of Electrical Panel room

HT Switchgear Room – Utility Breaker

The HT switchgear room is located in the ground floor of the building.

The HT incoming supply is received through an Ring Main Unit (RMU) belonging to TANGEDCO. This RMU consist of two Nos. Oil switches and One No. Oil circuit Breaker in the Tee off.

The observations made on this HT switchgear panel belonging to TANGEDCO is as below

The RMU has been installed way back in 1970 i.e., about 45 years ago and has outlived its useful service life.

The fault rating of this switchgear is only 250 MVA at 11 kV, whereas the present requirements are above 350 MVA at grid level.

The incomer oil switch from the HT 11 kV DP structure appears to have been not holding and the handle has been provided with a ‘stick” to hold the operating lever in position, which is highly not an acceptable practice from electrical safety point of view

o None of the protective relays appeared to be functional.o The oil has been changed many years ago

HT Switchgear Room – Consumer Breaker

The consumer side breaker is again an age old HT oil switch with fuse.

o Considerable oil spill was evident on the floor. This implies that the oil is leaking though the joints or elsewhere from the oil tank. There is a very much possibility that this oil leak can lead to reduction in oil level in the switchgear tank and this can lead to serious arcing and explosion hazard during fault interruption

o The switchgear is located in a not an easily approachable / inconspicuous location. Further the area is also very poorly

Operating handle of the HT oil switch held in ON position by means of a “stick”

Oil spill on floor

Narrow, congested and poorly illuminated room

illuminated. This is likely to result in time delay in switching OFF the breaker during emergencies.

o The ratings of the fuse elements are not legible and given the age of the installation the fuses should have deteriorated.

o The rupturing capacity of the fuse element is not evident.

Transformer room

o The transformer room is located adjacent to the HT switchgear room in the ground floor of the premises.

o The 11000 / 415 Volts transformer is oil filled type and is installed during 1970 and has outlived its codal life.

o Considerable oil spill / leak is observed from various part of the transformer tank / tap changing box / cable termination box etc., which indicates the poor health condition of the transformer.

o Being a transformer of yester years specification, it is considered that the oil being used will not be Polychlorinated biphenyls (PCBs) free. The PCB are toxic in nature and as per the latest codal provisions, the transformer oil should be PCB free version.

o As per the recent norms / guidelines, the transformer located in the basement portion of such high rose buildings shall be of oil free i.e., Dry type

o The tap changing available on the transformer is an OFF loa version which implies that the tap changing should be done when the transformer is switched OFF. It is observed that the tap changer available in the transformer is not provide with any mechanical or electrical interlock to ensure that the tap changing can be done only when the transformer is put OFF. In the absence of any such mechanical / electrical interlock on this tap changer, any inadvertent operation or any miscreant operation without putting OFF the transformer can lead to huge flashover and bursting of transformer leading to unimaginable catastrophic situation.

o The burnt oil drain line at the bottom of the transformer tank is seen directly connected to the normal drain, which is not correct. The oil should be drained into an oil soak pit instead of directly being discharged to a normal drain. There is very much probability that the oil in flame can float around the top layer of the water and spread the flame.

o Secondly this is also against the Pollution control norms.

Oil spill / leaks

Burnt oil drain pipe directly discharging into drain

Assessment of Earthing System

o Though earth strips are found laid and connected from the metallic frames of switchgear panel, transformer etc., the earth pits by itself for the HT / LT installations are not traceable at site.

o It obviously implies that the earthing system is not being maintained as per IE rules.

o Only the earth pits for the DG set are available at site.o The inspection of these earth pits revealed that the earth electrodes

and earth interconnecting flats / strips have also been highly corroded.

o The bolts and nuts in the earthing termination are also highly corroded.

The existing earthing system was observed to be ineffective.

Highly corroded earth electrode Earth electrode not traceable

Earth flats highly corroded

Assessment of DG set

The backup power supply requirement for this building is achieved by means of a 250 KVA emergency DG set. This DG set is located outside the building close to car parking area.

One the day of audit it was observed that this DG set was running even though utility supply was available. When enquired it came to be known that though the installed capacity of the transformer was 500 kVA, the contracted maximum demand is only 250 kVA. Further, the permitted demand is still lower than the contracted demand. Hence, in order to ensure that the consumed demand does not exceed the permitted maximum demand, this DG set was also being used as PEAK LOAD SHAVING purpose i.e., it is being used to meet the additional electrical load of AC plants.

It was also observed that this DG set is being operated for about 6 hours every day and more hours during summer months as this DG set primarily supports AC plants.

Though the practice of using DG set for Peak Load shaving is a general procedure prevailing in HT consumers, but such practices are restricted to absolute minimum as the per unit energy cost for a DG set is almost twice that available from utility.

The output power of this DG set is terminated on to a manual change-over switch. It is observed this change over switch is only an OFF LOAD type i.e., a switch which is not meant to be operated when load current is flowing through and should be operated only after ensuring that the loads connected to it are switched OFF and no current is flowing through the switch.

However, it was observed that this change over switch is being used an ON LOAD change over switch i.e., it is being operated with the LOAD ON, which is strictly prohibited and extremely dangerous. When enquired it was stated by the DG set operator that the existing switchgears in the main panel are of obsolete type and many often do not work.

Secondly it was observed that the cable terminations at this the change-over switch board was shabby. It was also observed that cable looping was done at the bus side, which is totally not acceptable.

The earth fault relay in the DG panel was also observed to be non-functional

Thirdly, it was also observed that the cables from the DG set were protruding into the car parking and maneuvering area. There is a very high probability that this cable can entangle to the bumper of any of the car and get pulled out. This will lead to a very dangerous situation and can lead to unimaginable catastrophes.

Cables haphazardly terminated and lopped in the change over panel board

Cables protruding in the carpark area

Assessment of Electric Circuit

The LT 415 Volts power supply from the secondary side of the transformer is terminated in a main LT panel. This panel has also been installed way back in the year 1970.

The incomer in this main LT panel is an LT Oil Circuit Breaker

This OCB is an horizontal drawout type

This OCB is provided with dash pot type (oil filled) over current relays. These dash pot type relays are the obsolete version of the protective relay family as on date. A closer look revealed that these relays were not functioning and the trip settings were totally irrelevant. Thus, the transformer is not protected against short circuit and earth faults.

This main panel is also observed to have lost its design integrity as it is observed that this has undergone additions / alterations on piece meal basis. The outgoing feeder switches are also of SFU type which again is significantly obsolete when compared to the present option of SDFs with two breaks per pole.

.

Switches added in the Main LT panel with tapping from main bus-bars

The 415 Volts LV power supply is further distributed from the main LT panel to an auxiliary panel board. In addition to this auxiliary LV panel several switches were observed to have been mounted on the walls of the switch room. The cables to these switches and as well as the cables from these switches to the loads were also observed to have been run haphazardly manner. The cable terminations are also not done in correct manner. Such cabling and terminating methods can give rise to totally unsafe condition.

Electrical Switch room (earlier AC plant room)

The 415 Volts LT power distribution from the main LT panel in the main LT switch room is also fed to a host of auxiliary panels available in the erstwhile AC Plant room. Here again it was observed that the panel room was totally in a mess with cluster of panels, most of them dysfunctional.

Most of the electrical connections were precariously done and dangling across the length and breadth of the LT panels.

The cable terminations were observed to have been made in a totally unacceptable manner.

Switches added in the LT switch room wall with improper cable termination and tapping methods from main panel

Switches added in the LT panel in AC plant room with improper cable termination and tapping methods from main panel

Electric circuit cabling in various floors

The insulation values of the feeder cabling were randomly measured. By and large the values were within the permissible limits.

The Panel boards for power distribution inside the floors of the premises were also verified for any glaring safety gaps. The panel boards were also checked for the balance of load distribution in the three phases. The voltages at the incoming and outgoing terminals of these panel boards were also measured.

The availability, adequacy and the rigidness of earth connection / termination in these panel boards was then examined. It was observed that in most of the panel boards, only one earth wire was found terminated. As per the Indian Electricity Rules, every panel board should be earthed with two independent earth connections.

Assessment of Lightning Protection System

As per IS the buildings needs to be protected against lightning strike in accordance with the risk assessment for that building category. The risk

Typical floor power distribution board

assessment considers the height of the building, its location, its purpose, the number of people expected to be available inside that building etc.,

By all probability it is certain that this building does need a Lightning Protection System.

It was understood that the lightning spike was installed many years ago in this building. It was observed that no lightning protection system is available as on date in this building. Hence, it is strongly recommended to immediately provide a lightning protection system for this building.

Assessment of Air-conditioning system

The office space in various floors have been provided with a mixture of DX type air-conditioning units comprising of

Window type AC units

Split Type AC units

VRF type AC units

The currents drawn by various AC units were randomly measured. It was observed that all the AC units were taking current in the reasonable variation range. However, it was observed that the filters of many of the AC units were clogged, which causes ice formation at the evaporator coils leading to lesser efficiency.

It was also observed that in some of the rooms the air flow from the AC plants were blocked by physical obstructions in its path like curtains, cupboards / cabinets, file racks etc.,, Such blocking of air flow path will lead to short cycling of the cool air and this inturn result in poor efficiency of AC units, besides causing strain on the unit.

It was also observed that in many of the floors, the power socket outlet and the voltage stabilizer have been mounted in a clustered manner, mostly near the stairways. Though this might offer a centralized access / control to various AC units located in that floor, it is observed that running small size individual power cables on longer runs will lead to higher voltage drop than leading a bigger size cable. Hence, there is a need for redistribution of AC plant load in a manner so as to have final branch circuits with smaller size conductors as close to the AC unit location.

Assessment of UPS

The power backup to data servers, work-stations and associated passive networking and communication devices have been achieved by host of smaller rated UPS spread across various floors. All these UPS are under Annual Maintenance Contract with a external agency.

All the UPS rooms were inspected and glaring unsafe practices were observed as below

Typical clustered arrangement of power sockets and voltage stabilizers for AC plants

Non- weather proof MCB enclosures used near outdoor AC units

o The batteries were both of Vented Type Lead Acid (VLA) and as well as Valve Regulated Lead Acid type (VRLA).

o The battery and the UPS were located in the same room.o The UPS cum battery room were poorly ventilated.o Many of the batteries were observed with passification due to reaction

of hydrogen crystals and sulphuric acid in the batteries. Continuation of such condition is likely to lead to further corrosion of the battery terminals leading to loosening of cable terminations. This inturn can lead to sparking and flashover leading to fire accident.

o The inter-cell connectors between battery banks were dangling and running crisscross the floor.

o No battery breakers are available near the battery bank. Such battery circuit breakers are essential to safeguard against short circuit.

o The battery surfaces were totally filled with dust which implies very poor maintenance.

o None of the UPS rooms were observed to be provided any passive smoke detection and alarm devices nor fire suppression devices.

o None of the UPS rooms were provided with any hydrogen gas concentration sensors.

UPS batteries stacked in floor without battery racksUPS battery inter-cell connections improper

No Battery breaker available near the battery bank

The Flooded or Vented Lead Acid batteries give off hydrogen and oxygen gas. The hydrogen gas being lighter rises to the top most point like ceilings and other enclosed space. If the battery room does not have good ventilation then the hydrogen gas concentration builds up. A 4 % concentration in the air forms an explosive mixture. The institution of Electrical and Electronics Engineers (IEEE) have defined the permissible of Hydrogen gas concentration. As per IEEE recommendations, the maximum permissible concentration of hydrogen gas is only 1 %. Thus all the UPS battery rooms need to be provided with adequate mechanical forced ventilation. The guideline given by m/s. Exide for hourly air exchange volume as below

Q = 0.05 X n x I (Cu.mtr/hr); where

Q = Air volume required for the room

n = No. of cells and

I = Value of the current.

MCB DB wiring left exposed in UPS room

Assessment of Pumps

Presently the Metro water is being received into a underground main sump. From the main sump, the water is being pumped into a secondary sump and then to overhead tank.

Pump room No.1

The primary pump is a jet pump located near the compound wall abetting the road.

This pump room is shabbily maintained. The name plate of the pumpset is not available / defaced due to

ageing The pump starter is mounted in an inconvenient position inside this

pump room. No guard is available for the Vee Belt. The motor pulley has considerably worn out No body earth connection is available for the pumpset. The wiring / cabling is precarious

Pump room No.2

This pump room is located at the side of the main building.

This pump room is shabbily maintained. The name plate of the pumpset is not available / defaced due to

ageing The pump starter is mounted in an unsafe position inside this pump

room. The live wires of the start / run capacitors are bare No body earth connection is available for the pumpset. The wiring / cabling is precarious with many number of joints

Assessment of Light fixtures

The lighting levels recommended as per Part 8 Section 1 table 4 of the National Building Code (NBC) 2005 is as below

General Offices 300-500-750 Lux

Computer Work Stations 300-500-750 Lux

Conference rooms, executive offices 300-500-750 Lux

The lighting in the various office areas in various floors of the building have been accomplished by combination of FTL and CFL light fixtures. The spot illumination levels were measured using lux meter at random spacing of the office areas.

The illumination levels observed at various locations in all the floors is available vide annexure

It is observed that the illumination levels measured in all the floors were considerably lower than the NBC recommended values.

There is thus a need for improving the illumination in all the office areas.

The improvement of lighting level, however has a consequential increase in energy bills also. An increase in the level of lighting by 10 lux however, increases the energy demand by 3.5 %.

The Energy Conservation Building Code (ECBC) 2007 specifies the Lighting Power Density i.e., the Total connected load of lighting system divided by the total built up area, for typical office space as 10.8 Watts / Sq.mtr

Hence, the improvement of lighting has to be approached on a more professional basis as below

a) Re-lamping of the fixtures to ensure the full working complement of lamps in each light fixture

b) Identifying those fixtures with longer working hours i.e, those light fixtures which are located in the interiors of the office area and retrofitting them with LED lamps.

c) Provide occupancy sensors and day light timers and re-wire the light fixtures so as to ensure need based switching ON & OFF.

Other General Observations on Electrical Safety point of view

Unused / Discarded furniture have been piled up in front of the main electrical HT, Transformer and LT panel room. This is against the recommended practice of keeping the electrical rooms and its vicinity free of any inflammable materials

None of the panel boards have any feeder identification / tagging. In the absence of such feeder tagging, it will be difficult to switch OFF particular feeder during emergency. Secondly there exists a high probability that the maintenance personnel get electrocuted due to switching OFF of incorrect feeder

All the switch rooms were very shabby and littered down with materials totally unconnected with electricity.The fire buckets near the DG set were rather being used as dustbins instead of fire buckets

None of the panel room have been provided with any fire detecting devices such as smoke sensor / heat sensor.The DG set is being operated by a person who does not possess any competency to operate the DG set.The HT and main LT switchgear panel is also observed to be handled / operated by this person. This is totally not acceptable. The electrical installations needs to be operated only by persons who holds the valid competency certificates issued by electricity board.No maintenance register / log book is being maintained, except for log book for recording the particulars of DG set running and fuelling. It is a good practice to have log books for operation and maintenance of electrical system.All the UPS rooms are observed to be with considerable dust and muck, which indicates a poor housekeeping.

Recommendations in brief for improving the electrical safety

Sl. No.

Recommendation in brief Time schedule for action

1 Advise TANGEDCO to replace the age old RMU with state of the art SF6 based compact switchgear panels

Immediate

2 Replace the age old oil filled transformer with dry type transformer. The new transformer shall be of low loss version conforming to the latest CEA guidelines

Immediate

3 Replace all the age old main electrical LT panels with compact compartmentalized versions. These panels shall be fitted with switchgears with appropriate fault breaking capacity. Till such time the panels are replaced, temporary feeder name plates / tags shall be provided for all main feeders. For the rest of the panels, the feeder tag shall be painted

Immediate

4 Redress the cable terminations in all panels Immediate

5 Improve the housekeeping in all electrical switch rooms

Immediate

6 The rubber floor mats provided in front of the main LV panel appears to have outlived its integrity due to aging. Replace these rubber insulation mats of appropriate voltage grade as per IS

Immediate

7 No rubber insulation mats were found available in any of the panel room in various floors. Rubber insulation mats to be provided in front of all panel boards

Immediate

8 The DG set operator needs to be equipped with competency certificate

Immediate

9 All temporary wiring needs to be removed and pucca wiring to be made

Immediate

10 Illumination levels to be improved to conform Immediate

to ECBC 2007 requirements

11 All UPS rooms needs to be isolated from battery bank.

Immediate

12 All electrical switch rooms to be provided with smoke and heat sensor

Immediate

Attachments

1) Filled in formats2) Photographs3) Illumination measurements

****

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Electrical Safety Audit

In process industries, fires due to electrical reasons are very probable, especially in industries that handle flammable

chemicals. In service industries such as information technology, telecommunications, business interruption losses due

to electrical hazards (fire in server room, damage of expensive communication equipment, loss of data, fire in cable

gallery, etc.) could be substantial.

Electrical Safety Audit will be carried out considering IS (Indian standard) guidelines, IE (Indian electricity) rules etc.

The safety audit carried out by Krishna Engineers & Consultants will cover the requirements of Electrical safety &

energy conservation.

OBJECTIVES OF THE SAFETY AUDIT

Design, Install, implement and maintain facilities which control safety risks.

Comply with statutory regulations and standards for controlling the risks.

Train the personnel working at work place for safety aspects, safe behavior and effective use of equipment's to

avoid any incident/accident.

Undertake reviews, analyze, evaluate and install optimum value available safety/ operational equipment's for

achieving the accident free operations economically.

Comply with statutory regulations & regulation of OISD (Oil Industry Safety Directorate), Ministry of Petroleum

and Natural Gas, New Delhi for safe operation.

BENEFITS OF SAFETY AUDIT:

Identifies loss producing events.

Assess the potential losses associated with the risk.

Identifies measures to minimize the losses.

Identifies system deficiencies

FOCUSSED REVIEWS

• IER Compliance

• Lightning Protection

• Electrical Hazards

• Shocks & Fires

• Protection Devices

• Earthing Systems

• Tests (IR, E, O/L)

• Equipment Layout

• Cable Size Adequacy

• Fire Protection

METHODOLOGY ADOPTED FOR ELECTRICAL SAFETY AUDIT

CONTENTS OF ELECTRICAL SAFETY AUDIT REPORT

Introduction

Overview of Electrical system

Observations and Recommendations

Lightning Protection System Evaluation

Electrical Hazards and Control measures

Hazardous Area- Observations & Recommendations

Review of Electrical Accidents and control measures

Review of Fire Hazards and Protection Measures

Electrical Maintenance Review

Review of Electrical Test Records & Test Procedures

Annexure (References/Guidelines)

Photographs

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