Split Circuits on CU

[chloebear]

Hi all,
I know it is reccomended that all new CU's are split or dual RCD but I have a particular CU change to do that has a problem with the space available and therefore to change the CU I am limited to a very small footprint CU. Is it acceptable within the regs to install a CU with only 1 RCD as the main incommer - there are only 5 circuits on the board. Probably not recomended but is it within the regs??

 

[steamboatwilly]

If you're pushed for space and can't move the CU why not just have a small CU with a mains switch and RCBOs on all circuits? That is effectively separating the circuits!

 

[chloebear]

no technical reason - just the normal one of cost

 

[steamboatwilly]

no technical reason - just the normal one of cost

Yeah, good point chloebear, they are still too damned expensive.

 

[tigerpaul]

No, just use a small board with an Rcd as the Main switch, not ideal but it will conform to the regs.

Rcbos is better, just give the customer the choice, and then its up to them if they want to pay extra for a better system.

 

[Spudnik]

No, just use a small board with an Rcd as the Main switch, not ideal but it will conform to the regs.

I dont think it will

314.2

 

[tigerpaul]

Hmmm....

I've seen a lot of little boards where the main switch incorporates RCD protection. Usually little 5 or 6 wayers in car parks, garages, outhouses, lift motor rooms, that sort of thing. Although I have seen them in small domestic dwellings also.

Obviously a fault is going to knock the whole installation out. But as the rest of the board is split up into different ways you can isolate each circuit to find the fault. Then the rest can be switched on again.

Isn't reg 314.2 simply asking for the installation to be split into seperate circuits so that you shouldnt lose the entire installation permanently.

Otherwise, why do they even sell RCD main switches?

 

[steamboatwilly]

<<Isn't reg 314.2 simply asking for the installation to be split into seperate circuits so that you shouldnt lose the entire installation permanently.>>

I guess it depends on whether you consider the Regs are there for the safety and convenience of the electrician or the owner of the property!

 

[trix]

Can you not have the dual rcd board turned 90.

Failing that, tell customer the problem and put it to them,

1) Alter the cudboard / compartment,

2) As has been sugested, rccbo's.

 

[ajelec10]

Hmmm....

I've seen a lot of little boards where the main switch incorporates RCD protection. Usually little 5 or 6 wayers in car parks, garages, outhouses, lift motor rooms, that sort of thing. Although I have seen them in small domestic dwellings also.

Obviously a fault is going to knock the whole installation out. But as the rest of the board is split up into different ways you can isolate each circuit to find the fault. Then the rest can be switched on again.

Isn't reg 314.2 simply asking for the installation to be split into seperate circuits so that you shouldnt lose the entire installation permanently.

Otherwise, why do they even sell RCD main switches?

Just because 'you have seen it done before' or ' they sell these at the wholesalers' don't make it right!

 

[tigerpaul]

Yeah I understand your point. It looks like the customer will just have to accept the more expensive rcbo's then.

 

[ajelec10]

It makes sense