Help needed on CU Upgrade

[Aquaman]

Hello all.

I am upgrading my bungalow fuse box to a new split load CU. My circuits on the fuse box were, 1. Cooker, 2. Heat pump and sockets, 3. Immersion heater, 4. Lights.

My new CU is a split load CU, to which I decided to separate the circuits between 2 RDC's in the following way, (From right to left) Main Switch, then RCD 1 with Cooker on a 32A MCB, then Immersion on a 16A MCB, then the lights on a 6A MCB followed by 2 spare spaces.

Then I put RCD 2 with the sockets on a 32A MCB, followed by the shower pump on a 16A MCB.

I did all of the tests such as, continuity, method 1 and 2, IR.

It's a bungalow, and it appears that the sockets are not a ring, but a radial so can't do end to end tests etc.

The problem is that the first RCD trips out as soon as I energise the lighting MCB and the 2nd RCD trips out as soon as I energise the sockets circuit.

Any help would be gratefully appreciated.

 

[Plonker 3]

Sounds like a borrowed neutral. More testing needed to find it.

 

[bartkusal]

how many neutral bars you have in your new CU

 

[Plonker 3]

Also why even though you know there is no continuity on the RFCs have you put them on 32a MCBs?

 

[markc123]

If the sockets are a radial and you have them on 32a have you got them wired in 4mm?

The RCD's trip when theres a leakage to earth, i suggest you go through the test procedure again + check that you haven't got the neutrals mixed up.

- - - Updated - - -

I am officially so slow at typing today, thats the second thread in a minute that Dillb has beaten me lol.

 

[trev]

The sockets were on one MCB/fuse rated at 32/30 amps, now they're on two.....
I'm not keen on "it appears that the sockets are not on a ring" if you did your testing properly you'd have found that out for definite

 

[shocking_eg]

all sounds a bit diy to me...

 

[R G]

Get Lofty in .....

 

[Aquaman]

I have 3 neutral bars.

I initially thought the sockets would be in a ring, but the end to end tests failed so assume it's a radial as nothing proves a ring circuit.

I thought it may be a borrowed neutral and will check each neutral bar tomorrow.

Anywhere else I should check for a BN?

Thanks

 

[trev]

Get Lofty in .....

Aquaman needs someone to help him mate not an executioner

 

[lofts]

whats up with you trev

 

[R G]

Entertainment at last , begining to think the night was wasted....

 

[Des 56]

Why have you decided to load the one rcd with both radial circuits,which presumably are supplying all your sockets and on 32 amp mcb (4mm assumed) ? What is the reasons for this decision

 

[bartkusal]

It was definitely a ring some time ago, I presume the T+E is 2.5 and 1.5 in your case if protected by 30A fuse, where now then you have 2 radials each on 32A mcb’s, NOT GOOD. Makes me question, are you really should be doing this…

 

[Aquaman]

You're right Trev. Will go through it all again tomorrow.
Thanks

 

[markc123]

oh dear.

 

[bartkusal]

You're right Trev. Will go through it all again tomorrow.
Thanks

Constructive criticism = good + helpful tips

Sarcasm and snotty comments = I was injured in Afghan so you can sleep easy, so help me please, if not, go serve in Helmand for 6 months and I will think about giving you some advice on how to stay alive.......!

I am sorry to hear that you were injured in your previous work, but with all the respect, it does not make you different from others really, whilst I understand that someone may feel sympathy for you

 

[trev]

It wasn't meant to be a snotty or sarcastic comment Aquaman. If you're not sure about whether or not it is/should be a ring drop all of the fronts off (without disconnecting them but remembering to de energise them) if there are two cables at every point of utilisation then it's a fair assumption that it was once a ring and it's now time to hunt the junction box.
Split the circuit into lumps and test for continuity on each leg you'll soon find the break

 

[markc123]

I've lost interest now after that last comment of his.

Completley irrelevant, and has said it to get sympathy.

Everyone on here has they're problems, granted some wont be as bad as what happened to the OP but still, its irrelevant and not for the forum.

 

[Plonker 3]

Helmand or not, people were questioning your ability to do a job. It doesn't give you a higher standing in this job regardless of your background.

Now you have your answers, return to the job and search for what you have been told to look for, you will almost certainly find the fault.

P.S please ensure the 32 amp radials are safe please.