Unearthed Lighting Circuit & Need for 5x RCD Test

[SW1970]

Hi, newbie here. This is a bit of a hair splitting question. Doing PIR and lighting circuit has no earth.

The Electrical Safety Council's best practice guide on domestic CU replacements where the lighting circuit has no earth gives rise to a potential outcome (if the customer refuses to fund lighting circuit upgrade to be earthed) of risk assessment, RCD being fitted and warning notices applied etc.

If during my PIR I establish the lighting circuit is already on an RCD, should I be recording the 5xIdn operating time value for a belt and braces job, or should I not record the 5x test result and consider it a next stage activity after discussions with the customer.

I guess this is all about a small conflict between my approach of doing a wholesome job and the opportunity to charge for more time.

Many thanks in advance
SW

 

[topquark]

As it's on an RCD protected circuit, you should test it as such and record your results accordingly. You should then point out the reason for the failure, with two possible corrective actions. Either remove the circuit from the RCD (as there's little, but not no, point it being there without a CPC) or provide a CPC for it.

I say little point as it's still possible for current to find a route out of that circuit via other means and still trip the RCD.

 

[morph]

you should be recording the rcd time regardless of the circuit, you should know this really , no offence intended

 

[SW1970]

Hi guys, thanks. I'm talking about the 5xIdn time, not the Idn time (which of course I'm recording). Cheers.

 

[topquark]

You should still record it. It could be an internal fault with the device that means it won't trip at 1x but will at 5x (hence the 6 tests).

 

[IQ Electrical]

Hi, newbie here. This is a bit of a hair splitting question. Doing PIR and lighting circuit has no earth.

The Electrical Safety Council's best practice guide on domestic CU replacements where the lighting circuit has no earth gives rise to a potential outcome (if the customer refuses to fund lighting circuit upgrade to be earthed) of risk assessment, RCD being fitted and warning notices applied etc.

If during my PIR I establish the lighting circuit is already on an RCD, should I be recording the 5xIdn operating time value for a belt and braces job, or should I not record the 5x test result and consider it a next stage activity after discussions with the customer.

I guess this is all about a small conflict between my approach of doing a wholesome job and the opportunity to charge for more time.

Many thanks in advance
SW

What are your reasons for the question?

I can't see why you wouldn't carry out the 5X I Delta n test if you're standing there doing the other tests?

If any RCD/RCBO is used to provide additional protection then it must be rated at 30mA or less and be tested at 0.5, 1 and 5 X I Delta n on both halves of the wave cycle.

 

[SW1970]

Hi IQ, thanks very much - that wraps it up nicely! Cheers.

 

[Deleted member 26818]

An RCD that fails the 1x test, will still meet the requirements of BS7671 if it passes the 5x test.

 

[IQ Electrical]

An RCD that fails the 1x test, will still meet the requirements of BS7671 if it passes the 5x test.

Where did the op mention failing the 1xtest?