RCD tripping on circuits after new board change nitemare

[vernam616]

Agree Tel.

You have just agreed with him disagreeing with your post of how its potentially dangerous, yet again this forum never ceases to amuse me with some of the comical members

 

[telectrix]

the problem could arise if you had too many lights on the 2 circuits for the 6A MCB. fair enough if wired in 1.5mm, you could uprate the MCB to 10A ( subject to no serious derating issues ), but if circuits are in 1.0mm, then you'd be in the fertilizer

 

[micknew]

Yes I completely agree with you, and take your point that its down to the client whether they want to pay and have it put right.

 

[micknew]

You have just agreed with him disagreeing with your post of how its potentially dangerous, yet again this forum never ceases to amuse me with some of the comical members

Didn't mean to make you laugh, honest.
Just pointing out the bleeding obvious.

 

[vernam616]

Definatley Tel, but elaborated too much on the original theory

The idea of couple the two circuits into one mcb isnt dangerous, unless like you say about derating etc... But then you could argue an "electrician" would know this

 

[vernam616]

Please tell me Mick what was obvious?

Ill tell you whats obvious and if you are an electrician shame on you as its basic stuff

If i couple them two circuits into one mcb and isolate it means no power is going out which means nothing is coming back on the neutral, thats what made me laugh, as its simple theory, if you cant grasp that you shouldnt be working on equipment or trying to tell an electrician that its "potentially dangerous" as the next electrician could get a belt

 

[T&Earth]

Hi I agree, but sometimes you get an old 4 way BS3036 board with NO extra play on cables with CPC & neutrals twisted together and to carry out these test with old board in is virtually impossible.

T&E

Never understood why after a cu change people start having problems due to existing faults, if you aren't prepared to address them then should you really be changing the board in the first place?

 

[ezzzekiel]

Regardless of anything, if you can't trace and fix faults then your in the wrong job.

Sharing an mcb as stated removes the borrowed neutral as it becomes a single circuit, prefer not to see it done this way but sometimes it's the only option

 

[SirKit Breaker]

Its no good clutching at straws.
It is because of things like this that we test the way we do.

Do all the tests, and in the correct order, you will then know if you have a problem with the fixed wiring, and you will be able to identify the reason for the RCD trip, especially if you have a very low IR result, or some interconnection with your circuit.

I will assume that as you have done this job, you are registered or have notified if not, and so you are competent to Inspect and Test, so i dont need to go in depth with these testing procedures, it is all in your GN3 anyway.

Cheers.............Howard

 

[Farmelectrics]

Vernal what would happen if you didn't test before hand and fitted new board and the ir tests were that poor due to old cables that they wouldn't take rcd board rewire would be needed better to no condition of installation before hand

 

[vernam616]

You use a bit of common sense and have a think of the age when taking board cover off, the surroundings also give a good indication


Of All the boards ive changed now its never bit me in the arse( and trust me its a hell of a lot of boards)

 

[Farmelectrics]

That a a fur shout but isn't it still better to do some per testing work it's only a couple of hours work and can save you a load of hassle

 

[mheyes]

I think you should have done an EICR before swapping the CU. It is a good reference to accompany an electrical installation certificate. It goes a long way to show what you did and what you did NOT do. If something did go wrong with the job six months down the line you will need all the proof you can get, Remember in a court of law ‘HEAR SAY ‘ is not admissible as evidence ! ! ! !

 

[Engineer54]

That a a fur shout but isn't it still better to do some per testing work it's only a couple of hours work and can save you a load of hassle

Shouldn't need a couple of hours, you only need to do some quick confirmation tests on any rings and lighting, (borrowed neutral syndrome..lol!!) That should be sufficient for most homes. The problems come, if you DO find things wrong!! lol!!