RCB Tripping Advice Please

[chris301up]

........It worked before. You touched it. It now doesn't work and you don't know why.....

My point exactly. All I have done is added a 60amp junction box with a short 6mm cable extension, which isn't connected to anything.

 

[Bobster]

My point exactly. All I have done is added a 60amp junction box with a short 6mm cable extension, which isn't connected to anything.

The fact that when you disconnect this, the fault is gone, points to you either installing a damaged cable, or incorrectly.

I presume as you are DIY you have nothing available to test with?

 

[chris301up]

Yes I am DIY. I am just going to have another look at this shortly. Have a multi-meter if that helps?

Could the junction box be faulty is also a question at the back of my mind?

 

[Bobster]

Highly unlikely.

 

[Deleted member 9648]

Yes I am DIY. I am just going to have another look at this shortly. Have a multi-meter if that helps?

Could the junction box be faulty is also a question at the back of my mind?

Can you confirm the cut end of the cable is properly insulated/safe and the cores separated?

 

[chris301up]

Okay everyone. Have had another look at the problem this morning and can confirm that it looks like the junction box is the cause. When connecting just the junction box to the existing wiring the RCD trips. No extension cable attached at this stage.

Just a bit of trial and error! I connected a standard 30amp junction box, together with the new extension cable, and all is well. RCD not tripping. Nothing else connected to the cable. I'll order another junction box and go from there. Thanks everyone for your kind advice

 

[Andy78]

Well if you have no idea what you are doing and have no way to test if it will be safe then I suppose trial and error is your only way to diagnose a fault. Not that you have done that for sure.
Don't forget to cross your fingers when energising to replace basic test procedure.

 

[DPG]

Could you post a picture of the junction box - I'm intrigued to see what the issue is.

 

[Deleted member 105166]

Yes I am DIY. I am just going to have another look at this shortly. Have a multi-meter if that helps?

Unlikely... in fact probably unhelpful in that if you don't know what you are doing, you could end up hurting yourself. Read this thread. If you value yours and your family's lives and your home, you will call an electrician.

 

[Deleted member 9648]

In 40 years working I have never had a faulty joint box.

 

[Marcus Vaughan]

In 40 years working I have never had a faulty joint box.

I agree. It doesn’t make sense. I guess we’ll never know what’s really gone on without a photo...

 

[HappyHippyDad]

Okay everyone. Have had another look at the problem this morning and can confirm that it looks like the junction box is the cause. When connecting just the junction box to the existing wiring the RCD trips. No extension cable attached at this stage.

Just a bit of trial and error! I connected a standard 30amp junction box, together with the new extension cable, and all is well. RCD not tripping. Nothing else connected to the cable. I'll order another junction box and go from there. Thanks everyone for your kind advice

It is possible that the Junction box is faulty but EXTREMELY unlikely. It would be simple to test if it was the junction box Chris as you would just test for continuity between the neutral and earth terminals. If there is no continuity then the junction box is not faulty.

It is worrying that you have decided by 'trial and error' that a circuit is now safe to use. I realise you are trying to help your son save some money and probably also enjoy feeling useful to him, but you cant possible liven up that circuit until you have had an electrician look at it. Your son's safety is more important than your need to feel/be helpful.

 

[chrisdungan]

Sounds like a neutral /earth connection .
either in the j box or cable end.
have you considered a crimped joint with HD shrink tube instead of a j box

 

[chris301up]

Right everyone. Had a new J/B and fitted it and all is now well. Sorry I don't have one of these so called 'smart phones' so was unable to take any pictures. When this issue raised 'it's ugly head' I did consider crimp and heat shrink tubing as an alternative, but has I'd already contacted the supplier thought I'd wait until I'd tried the replacement.

I have an old friend of mine who works for the council and is a qualified electrician, but is currently off work at the minute following a knee operation, and he said he will be more than happy to call round when he can to check this out for me.

I will say at this point that I tried several other electricians before contacting my friend but none would entertain calling round and checking this out for me.

Thank you all for you kind help and advice

 

[HappyHippyDad]

Right everyone. Had a new J/B and fitted it and all is now well. Sorry I don't have one of these so called 'smart phones' so was unable to take any pictures. When this issue raised 'it's ugly head' I did consider crimp and heat shrink tubing as an alternative, but has I'd already contacted the supplier thought I'd wait until I'd tried the replacement.

I have an old friend of mine who works for the council and is a qualified electrician, but is currently off work at the minute following a knee operation, and he said he will be more than happy to call round when he can to check this out for me.

I will say at this point that I tried several other electricians before contacting my friend but none would entertain calling round and checking this out for me.

Thank you all for you kind help and advice

Thanks for the update Chris and really glad you decided to get an electrician to have a look. It's good to hear how it ends. Still can't quite believe (without seeing it with my own eyes) that it's the junction box though.

 

[telectrix]

Thanks for the update Chris and really glad you decided to get an electrician to have a look. It's good to hear how it ends. Still can't quite believe (without seeing it with my own eyes) that it's the junction box though.

it might well be the junction box if the cat has pi$$ed on it.

 

[freddo]

Sounds unlikely but I guess anything is possible. Here is a brand new socket with a N-E short, the fault was found during dead testing of a new installation. The fault was an assembly screw trapped inside the socket.