Friday, 24 October 2008


Safety Inspection on electrical installation which receives electricity supply from Tenaga Nasional Berhad (TNB) or other supply authorities in Malaysia through a circuit breaker more than 100A (other than domestic installation) is mandatory. This is clearly stated in Clause 66 of Malaysian Electricity Regulations 1994 which is to be read together with Electricity Supply Act of Malaysia 1990 (Act 447).
The Competent Person, Duties of Inspectors and Frequency of Inspection on the installation are stipulated in Clauses 67, 68, 69 and 70.
Recently, I had an opportunity to carry out safety inspection on an 11-kV installation together with Engineers, Technicians and Chargeman from JKR Elektrik Selangor.
Append below are some of the findings which I like to share with others on the observation and actions to be taken to overcome the shortcomings.

Photo 1A
The VCB truck has been removed for maintenance. The barrier provided for is inadequate to prevent access by unauthorised person. Accident could happen by just lifting the shutters (yellow & red) and exposed oneself to the live 11-kV busbar/cables behind the shutter. No warning notice was erected.
Solution :
The bus bar and circuit/cable shutters (photo 1B) should be locked. VCB opening should be blocked by using a bigger cover with DANGER and WARNING signages posted on it e.g. BAHAYA, JANGAN HAMPIRI PANEL INI..

Photo 1C
The RC slabs of cable trench cover are broken and sharp concrete left-over are risk to personnel especially at night.
Solution :
The trench could be filled up with sand and rendered with a thin layer of plaster at the same floor level. This will enable future access to the trench should a new circuit to be added.

Photo 1D
The First Aid Chart displaying The Holgger-Nelson's treatment method has been banned by the International Red Cross Society.
Solution :
A new first aid chart describing Cardiac Pulmonary Resuscitation (CPR) shall be installed to replace the existing one.

Observation :
2A & 2B - missing screws to the 11-kV panels need to be replaced immediately and URGENTLY. This is because, the panel has been designed equipped with the necessary screws to prevent the panel from being thrown out during untoward accident.
2C & 2D - DC supply system is very critical to the safe operation of high voltage equipment. DC is used to power up tripping coil of circuit breaker (open the circuit breaker during fault or when required), power supply to protection relays, etc. As such, DC supply system must always be made available to the panels and it must be maintained properly. Every care must be takento keep the DC system in tip-top conditions by following maintenance schedule recommended by the manufacturer.

Observation :
Switchgear labelling may seems trivial to some but actually it could cause unnecessary lost of lives if it is taken for granted.
Switchgear labelling must at all times be correct and updated immediately if necessary because the label on the panel is always referred to during any activity involving the panel (data-taking, switching, maintenance, replacement, etc). Wrong labelling on the panel could cause wrong switching to me made which may result in accident or lost of power supply. As such, the labelling on the panels must always be determined, updated, corrected and concise to ensure all activities carried on on the panel is always right and accident-free.

Observation :
4A & 4B - show the readings displayed by the respective ammeters and voltmeters of the incoming supplies (no. 1 and 2) from Tenaga Nasional Berhad. The ammeters show that the two incoming feeders from TNB are carrying 40A and 160A respectively.
From those readings, the Maintenance Engineer should always try to balance-up the two feeders as close as possible. This will ensure that both feeders are almost equally loaded and should one of the feeders experiences a power disruption, only about 50% of the installation is effected. If the shown readings are left unchanged and should the higher-loaded feeder experiences a fauly and trip, 80% of the installation load will be disrupted.

Observation :
Gauge 5A shows that there is still gas in the tank while gauge 5B shows that the gas has totally discharged from its tank. Maintenance personnel shouls always check that the gas content of the appropriate fire fighting system must always be made available to face any unwanted accidental fire so safe guard the installation.
Temperature gauge of 5C shows the oil temperature recorded of an oil transformer. This temperature gauge also acted as an Alarm and Trip protective device that will permit or stop the flow of current into the transformer depending on the condition of the transformer temperature. So, every gauge function must be fully understood by the maintenance personnel so that a right and prompt decision could be made to ensure the availability of power supply to the installation is always safely maintained.