Newbie screaming for help with constantly tripping RCBO.

[Cyril Eaton]

I'm replacing an old MEM Fuse Board in my garage with a Small CU. The power was supplied from the ground floor ring main, so I've removed that and added a separate circuit in the main CU with its own RCBO. Problem is, the RCBO trips every time I turn something on and I can't understand why. Apart from the supply cable - main CU to new CU - the cabling is exactly the same as yesterday and was working so I can't understand why there's a problem. Help desperately needed as I have 3 freezers in the garage.

 

[Baker1988]

Have you done any testing? Check there is no short to earth. You say every thing is the same but how can it he if you have taken away the power from the ring and put a new cable in to feed it.

Sounds like maby the cable is damaged and needs to be tested.

If you used twin and earth then it is very easy to damage the cable and cause a short.

 

[telectrix]

I'm replacing an old MEM Fuse Board in my garage with a Small CU. The power was supplied from the ground floor ring main, so I've removed that and added a separate circuit in the main CU with its own RCBO. Problem is, the RCBO trips every time I turn something on and I can't understand why. Apart from the supply cable - main CU to new CU - the cabling is exactly the same as yesterday and was working so I can't understand why there's a problem. Help desperately needed as I have 3 freezers in the garage.

my area of operation. sen d me a pm and i'll come and sort it.

 

[littlespark]

Does it trip as soon as you switch on the CU, or when you turn on a freezer?
Take up Tel's offer. Will find the problem in 5 minutes

 

[dksanders]

As he's replacing an old fuse board with a new one and now protecting it's feed with a RCBO, he most likely has an IR fault in the garage wiring that the old non RCD board couldn't see.

 

[Ib≤In≤Iz]

My advice would be to take up Telectrix's offer. Without the right test equipment and experience you could be looking for the fault forever.

 

[HandySparks]

A pic of the wiring inside the new CU might help (or might not). Also a pic of the wiring to the RCBO.

Pretty hard to diagnose remotely without a full set of tests.

 

[Cyril Eaton]

You'll have to help me with PM facility. As it says - I'm a newbie.

 

[Cyril Eaton]

It doesn't matter which circuit I turn on, Power, Freezers or Lights, any load trips the RCBO. Obviously need to get my hands on an Insulation Tester.

 

[MDJ]

If I had my way you would be in court, changing a distribution board and having no idea how to sort out a minor issue should be a criminal offence IMHO. Lets step back actually, are you an Electrician? have you got any test kit? Popcorn ready.

 

[Cyril Eaton]

If I had my way you would be in court, changing a distribution board and having no idea how to sort out a minor issue should be a criminal offence IMHO. Lets step back actually, are you an Electrician? have you got any test kit? Popcorn ready.

I trained as an Electrician with the RAF in 1975 and I've been doing it since. As I'm now retired I don't have a full range of professional test equipment, just my trusty Multi-meter. I'm sure this is something trivial, but I'm struggling to find the answer and thought I would try and get some help in case I'm missing something bleeding obvious. Most of the comments have been helpful.

 

[MDJ]

Well firstly thanks for your service, I have high regard for service personel. Now that aside you should know better as an ex spark, changing a board and connecting existing circuits to it without testing is literally appalling, sorry but there you are, you will get the odd nice comment but it will be few and far between I am afraid.

 

[Octopus]

So you are familiar with Part P of the building regs then?

 

[Wilko]

Hi - I would get hold of some extension leads sharpish and get the freezers back on power. It will be tough to find the fault(s) without test gear.

 

[MDJ]

Hi - I would get hold of some extension leads sharpish and get the freezers back on power. It will be tough to find the fault(s) without test gear.

Too true, there may be beer in the fridge.