RCBO in a 2 way

[robmw]

Hi Every one. new user, first posting.

I mainly like to read the posts but i can't find an answer to something i need to know. I have just bought a house which about 25 years ago had an extension on the front. The old Wylex fuse board is in the centre of the house. This was kept there with all the original wiring to it. However the Main supply fuse and the meter was moved to the new front door 4.5 metre away.

There is now a big fat Twin & earth (16mm i think) running from a main switch with 60Amp fuse next to the meter to the old Wylex consumer unit in the middle of the house.

In time i am going to get the house rewired, but for now my question is this.

Can I swap the main switch with the 60Amp fuse which is by the meter, for a 2way garage consumer unit? In this 2way consumer unit i want to put in a 50Amp RCBO to feed that 16mm twin & Earth to the old Wylex board, which then feeds the whole house. 50 Amp is enough for me, I have gas oven, hob and I dont have an electric shower or electric immmersion heater.

Can A Wylex RCBO fit into a NH series 2way garage consumer unit?

I hope you can understand what i am trying to explain.

This will be done through building control, i have got my 17th edition, 2391 and calibrated meters.

Thanks for your help in advance.

 

[telectrix]

you would need to fit a 80A main switch in with the RCBO in order to have 2 pole isolation, and you would have the problem of a fault tripping that RCBO taking the whole installation out. bad idea.

 

[eganelectrical]

What earthing system do you have? So what your trying to say is make the old Wylex board a sub main and the new 2 way the main??

 

[robmw]

you would need to fit a 80A main switch in with the RCBO in order to have 2 pole isolation, and you would have the problem of a fault tripping that RCBO taking the whole installation out. bad idea.

Hi thanks for your quick reply. As i said in my post i would be putting a 2 way garage consumer unit as main. This comes with a 100A double pole main switch. In one of the way's i would put a 50Amp RCBO. This would give me a double pole isolating switch and RCD protection.

As for a fault tripping everything out being a bad idea. on the contrary i think it's good because i'll identify what circuit is causing the tripping and deal with it.

 

[Brightspark2]

You dont really want an RCBO protecting the whole house as an earth fault causing operation of the RCBO would leave the house with no power at all.

 

[Brightspark2]

and you would have the problem of a fault tripping that RCBO taking the whole installation out. bad idea.

Oops didn't see this bit...

 

[robmw]

What earthing system do you have? So what your trying to say is make the old Wylex board a sub main and the new 2 way the main??

Thanks for your quick reply, i have a PME system fed from from overhead lines with no earth rod. I've already done my Bonding to gas and water as no need to notify.

 

[telectrix]

as i said. bad idea. fair enough saying you will find the fault, but what if you are away for a few days and it trips. freezer contents turn to mush. be batter to fit a 63A MCB and upgrade the old CU to a dual RCD unit, or RCBO each circuit.

 

[Brightspark2]

As for a fault tripping everything out being a bad idea. on the contrary i think it's good because i'll identify what circuit is causing the tripping and deal with it.

It wont comply with regulations. You wouldnt think it was a good idea if there was a fault on the lights at night causing you to lose power to the whole house. Sockets are off, heating the lot. How would you be able to deal with that?.

Circuits need to be separated/segregated to avoid this. To be fair the fact you think this is a good idea shows your lack of understanding and competence.

 

[telectrix]

to be fair to OP< i think he's thinking of protecting the tails to the CU. it's only if he fitted new tails would need to RCD protect them. existing do not have to comply with 522.6.101

 

[robmw]

There's no need to be like that! How come is doesn't comply with regulations?

My previous house, I updated my consumer unit to a Split board with Dual RCD which everything in the house feed from a RCD covered circuit and i got that passed with no problem and it didn't cause tripping.

This is what i would do in the middle of the night. Pull out all fuses, Reset RCBO, Put each fuse back in one at a time, if it trips, leave out till morning and sort.

I'd like to add, i've already done an insulation resistance test, R1 +R2 test for all the circuits already. all are perfectly fine.

 

[Engineer54]

I can't see he's problem?? He's talking about rewiring the house in time, why not do the work then. As he's stated this present installation has been giving service to this house for 25 years, why chop it about now, i can't really see the point!! Do whatever needs doing at the time you decide to rewire the house. If you ''Must'' start fiddling with the installation change the CU, at least you'll then actually be improving the overall safety and integrity of the installation!!

 

[Had8Lives]

I would of said (depending on access) It would be worth running a new supply cable for the lights and put them on an RCBO in the new 2 way CU.

 

[Engineer54]

I would of said (depending on access) It would be worth running a new supply cable for the lights and put them on an RCBO in the new 2 way CU.

Now were starting to get into the ridiculous!!

 

[telectrix]

There's no need to be like that! How come is doesn't comply with regulations?

My previous house, I updated my consumer unit to a Split board with Dual RCD which everything in the house feed from a RCD covered circuit and i got that passed with no problem and it didn't cause tripping.

This is what i would do in the middle of the night. Pull out all fuses, Reset RCBO, Put each fuse back in one at a time, if it trips, leave out till morning and sort.

I'd like to add, i've already done an insulation resistance test, R1 +R2 test for all the circuits already. all are perfectly fine.

BGB reg. 314.1