Consumer Unit Electric Safety question

[CBX]

Hello everyone

The sticky thread regarding Electric Safety advises that you should test for Live before and after isolating.

I saw a UK Youtube video (https://www.youtube.com/watch?v=MERh6H6AjdY) showing proper procedure for testing for dead within a consumer unit.

Test voltage indicator on proving unit
Unload board, switch off main isolater
Test load side:
- E & L
- E & N
- N & L
Retest voltage indicator

At no point does he test before isolating. Is this correct?

Whilst a proper voltage indicator is desireable is there a good reason a quality multimeter can't be used in a pinch, assuming the earth is proven to be good, probes are properly insulated, mutlimeter set up correctly etc?

 

[Chri5]

Why would you test for dead without isolating?

I'm not sure I understand your question.

 

[stillp]

It makes sense to test that a circuit is actually live before isolating it, and then test for dead after. Otherwise the isolator might have failed but the circuit de-energised somewhere else.

 

[viewer]

Also few DIY people will have a testing unit, so the check on live proves that the tester is working.

 

[Risteard]

Whilst a proper voltage indicator is desireable is there a good reason a quality multimeter can't be used in a pinch, assuming the earth is proven to be good, probes are properly insulated, mutlimeter set up correctly etc?

There is. The wrong setting could cause the multimeter to explode. It is unlikely to be GS38 compliant.

 

[FDJ]

Whilst a proper voltage indicator is desireable is there a good reason a quality multimeter can't be used in a pinch, assuming the earth is proven to be good, probes are properly insulated, mutlimeter set up correctly etc?

Obviously a multimeter can be used but its just not recommended.
Apart from safety reasons given above, multimeters are very high impedance and can give a false indication due to this.
An "approved" voltage detector won't break the bank.
Frank

 

[CBX]

So a better test might be:

Test voltage indicator on proving unit
Test load side:
- E & L
- E & N
- N & L
Unload board, switch off main isolater
Test load side:
- E & L
- E & N
- N & L
Retest voltage indicator

 

[PrenticeBoyofDerry]

It is not correct or incorrect but you are testing for dead not live, so the procedure would be
Identify circuit
Isolate
Lock-off
Prove voltage indicator
Test for dead across all conductors
Reprove voltage indicator

 

[CBX]

Thanks for all the responses.

Interesting that it seems to be a matter of opinion whether to test while live first or not if you are testing for dead. I think I'ld choose to test for live first if only to ensure the main switch is working correctly before isolating.