Safe Isolations & Precautions before Working on Electrical Equipment

Question 1

List FIVE precautions that should be taken before any work is carried out on electrical equipment

Answer 1

• Undertake a Risk Assessment
• Permit to Work
• Correct PPE is used
• Isolated and Tagged (lock out, tag out)
• Remove Circuit Breakers
• Prove Dead using live line tester

Question 2

Identify THREE additional precautions to those already answered, if it has become essential to work near live equipment

(List FIVE precautions that should be taken before any work is carried out on electrical equipment)

Answer 2

• Put up Guards
• Put warnings around the live equipment
• Ensure another competent engineer is in attendance
• Rubber Matting
• Use Approved Insulated Tools

Question 3

Explain the procedure to be taken for taking the a.c generator off electrical load

Answer 3

1), Ensure a running generator is on load and capable of taking the extra load.
2), Increase fuel to the incoming generator 1 & Decrease fuel to the generator 2 being taken off.
3), Monitor load sharing until the generator 2 to be taken off load carries only 5-10% load.
4), Open circuit breaker of the off-loaded generator 2. (Isolate)
5), Allow the generator 2 to run in idle for a few minutes to cool and then stop the generator 2.
+ Monitor the remaining generator 1 to ensure it handles the extra load stably.

Question 4

Explain the procedure to be taken for isolating the machine in order that work may be safely carried out

Answer 4

1), Shut off fuel supply to the generator
2), Shut and lock the start air valve
3), Drain the start air system and leave the drain valve open
4), Post a maintenance notice on the control panel
5), Stop the generator
6), Ensure lube oil pre-lubrication pump is turned off
7), Drain jacket water system if required
8), Engage the turning gear to prevent rotation
9), Rack out and lock the generators main circuit breaker

Question 5

State THREE underlaying causes of electrical equipment failure

Answer 5

• Corrosion
• Misuse
• Overloading
• Single Phasing

Question 6

State the precautions to be taken before working on the switch board

Answer 6

• Risk Assessment
• Inform Crew
• Permit to Work
• Check for live equipment nearby and avoid unintentional contact.
• Isolate the switchboard, turn off power & remove circuit breaker.
• Lock out, Tag out
• Ensure dead and remove any residual voltage using potential indicator.
• Use Appropriate PPE
• Ensure tools and equipment used are rated.
• Place Signage and Barriers