Rcd Problem

billythesparx · Oct 12, 2013

Hi all you electrical genii,

Here is a puzzler for you (well, it is to me!). Called to a house owned by a friend of mine. He (a DIY hero, if you know what I mean) has wired it himself. All was well until recently, when his tenant reported an unusual fault. The con unit is a split board, with power circuits RCD protected and lighting unprotected, as is usual. Often, when the kitchen light is turned on, the RCD protecting the power circuits trips. The lighting circuit stays on, as you would expect, but the RCD trips. When turned back on, all appears well for a few minutes, then it trips again. There is no obvious connection between the lighting circuit and any power circuit, as indeed there shouldn't be. Any thoughts?

NozSpark · Oct 12, 2013

Do the two neutral bars have a link fitted?

SPECIAL LOCATION · Oct 12, 2013

First of all you have to decide..

Are you doing any investigation work as a charitable not for profit venture..

or are you a business doing it as proper renumerated work proportional to reasonable costs.?

e.g. The phrase looking at something for a mate / friend / neighbor etc..

often means people start forgetting basic business practice and end up doing loads of work for very little return.

If you find stuff that is far more involved than you first thought it could be loads of hours of investigations.

Next: forget how well or how little you know the bloke....

Keep the facts at the front of your investigations...

DO NOT ASSUME ANYTHING YOU HAVEN'T PROVED YOURSELF!!

so the next decision is..

He is a landlord (as you said it was the tenant who had the problem) AND he has wired the property himself...

Therefore under his legal duty of care to his tenants he should have had the work done and tested properly..

e.g. by a competent person to BS7671 guidelines.

So either

1/ he IS competent, and so should be able to fix the fault himself..

Using his previous test results & certificates as guidelines to the composition of the installation and each circuits characteristics etc.. etc..

OR

2/ He is NOT competent and has (a) neglected his duty of care (b) Not tested anything correctly...

If he is not competent then you need to go back to basics and do full test and inspection on the whole installation to verify its safety and compliance with BS7671..

During those investigations you will probably find the cause of the fault

So my first step would be to quote him 1 full days labour to do a comprehensive PIR and

then you will be in a position to evaluate any further remedial actions required.

opcorn