Nightmare of a day. RCD tripiing under any load

[brizospark]

Have had one of them days. I had a board change to do and a few other bits and bobs so everything was going great until I tried to put power back on.

Basically I have replaced a 3036 board with a split load Wylex board. One half of the board is working fine but the other half's RCD is tripping as soon as anything is plugged into it.

If I remove all plugs from sockets then the RCD holds but as soon as I plug anything in, kettle, sky box, TV, it trips instantly. On this side of the board is the cooker, 1 x lighting circuit and 2 x ring mains, funny enough the RCD isn't tripping when the lighting circuit or cooker is on.

Now I have checked that I have neutrals from correct circuits going to the correct neutral bar, several times and these are OK. I tried replacing the RCD itself with the one that was OK and it still tripped. What else is strange is that the kitchen ring is on the side of the board which is fine but if I plug anything into a kitchen socket the RCD which isnt even protecting this is tripping!! I opened up sockets and everything looked OK but it was getting late on so I replaced the offending RCD with a main switch I had in van just so the couple have power on tonight before I go back again tomorrow. Switched on with RCD removed and everything fine.

Anyone had experience with this problem before? Any advice much appreciated

 

[brizospark]

Is a borrowed neutral generally when its been wired in singles?
Im qualified but mainly done new builds since i qualified so i have never come across it.......yet!!!
Thanks

Daz a not necessarily a borrowed neutral is where a neutral has been taken from a different circuit to the live. Common in lighting circuits.

 

[brizospark]

As above damaged cable at JB under floor solarman

 

[davethsparky]

So you guys who don't bother testing are happy to give the customer a surprise when the bill doubles at the end of the job?

I don't generally test at the time of quoting, I do test before taking the old CU to pieces though.
I always advise the client that there may be faults in the system and that I will quote seperately to fix them if necessary. But I will fix little faults and things like borrowed neutrals without charging the client any extra. I usually allow a bit of extra time on the job to cover these things and if I finish much quicker than expected with no faults to fix then I will knock a bit off of the bill to reflect this.

 

[Dubbo]

Even if if you didn't test before changing board, that's the risk you take, but shouldn't you have found the faulty circuit during dead tests? Don't think it's very professional just powering up without testing and what readings do you put on your cert?

 

[trev]

Dubbo, if you're the kind of bloke that powers up without testing you're not the kind of bloke that issues certs mate.

 

[brizospark]

So how the hell do you quote for work, find out if bonding is upto scratch, what size DB to take to the job?

As previously stated I carry out a visual

 

[Guitarist]

I think that we all accept the fact that there may be additional issues arise when we actually start the job. The point here though, is that for the sake of 10 mins of basic testing (which also lets the customer get to know you), you have a much better idea of what could possibly bite you when it comes to doing the job. This gives the customer a much better idea of whether they can afford to have the work done, plus gives you a much better idea of how much time to allocate the job.

 

[Plonker 3]

So you visit the property at least once, a visual inspection of the bonding doesn't normally mean anything, I have come across several times cables connected either end only to find they have merely stuffed a cable into a cavity to make it look like it is there.

 

[brizospark]

So you visit the property at least once, a visual inspection of the bonding doesn't normally mean anything, I have come across several times cables connected either end only to find they have merely stuffed a cable into a cavity to make it look like it is there.

This gets checked as I am carrying out job. By the sounds of it you are doing most of the work before you have even quoted Dillby

 

[brizospark]

Even if if you didn't test before changing board, that's the risk you take, but shouldn't you have found the faulty circuit during dead tests? Don't think it's very professional just powering up without testing and what readings do you put on your cert?

I would agree that under most conditions that powering up before testing isnt right but on a domestic CU change where there are no circuits added/altered and everything was functional before then like Dr Pepper says the worst that can happen is a tripped RCD, as in this instance, the fault was rectified. This is getting boring now!

 

[sima24]

So you do the bonding continuity, global ir, and i presume ze (possibly one of the most important). Fair play if you do, but i dont unless its being paid for. May aswel do R1 R2 & be done with it lol

 

[trev]

the worst that can happen is a tripped RCD

I hate typing this but, roflmao!

 

[Dubbo]

I would agree that under most conditions that powering up before testing isnt right but on a domestic CU change where there are no circuits added/altered and everything was functional before then like Dr Pepper says the worst that can happen is a tripped RCD, as in this instance, the fault was rectified. This is getting boring now!

Sorry it's boring you but I was originally trying to help, if I new you had been to lazy to do IR tests I would of left you to it,

 

[wersolaruk]

I do the same tell customer we have to do a full test which may add cost, but I include £40 to each quote which is refunded if no faults are found. Works a treat for me

 

[Dubbo]

I would agree that under most conditions that powering up before testing isnt right but on a domestic CU change where there are no circuits added/altered and everything was functional before then like Dr Pepper says the worst that can happen is a tripped RCD, as in this instance, the fault was rectified. This is getting boring now!

And the worst think that can happen is not checking all the accessories and leaving an exposed live part that you didn't know about and that you are now responsible for