Altering a Split Load CU

[tomathy]

Currenly have a 6+6 CU which is full to capacity.

One of these ways (16a, on the RCD side) is used to supply an outside socket and (via a S/FCU) a floodlight. As with most outdoor supplies this has occasionally tripped the RCD, long story short, I'm intending to replace this MCB with an RCBO.

As the non-rcd side of the CU is full, I am looking to "change the position of the split" in the CU to essentially create a 7+5 way board. I can see how I can cut the rcd side busbar easily, and change the neutral connection to the other side, but how to supply non-rcd protected live to the new RCBO?

My initial thought would be to use a small section of cable between the adjacent mcb connection to the busbar and the supply live on the new RCBO to create a link. Would this be acceptable?

What size cable would be required for such a link? Initially my thought was 25mm, same as the meter tails as there is no O/C protection for this cable, however I notice that the cable feeding the RCD is only 16mm, would this size therefore be okay to use? Could I use even smaller cable (say 2.5mm, 4mm?) as the RCBO is only rated to 16a.

Thanks in advance,

Tom

 

[RF Lighting]

Click Here

 

[tomathy]

Thanks RF, this MK busbar would be suitable for all CUs, yes? I assume the spacing is standard...

While we're at it, does anyone know if it is possible to get insulated busbar? If so, does anyone know where I can get some?

 

[RF Lighting]

Yes the MK busbar will fit virtually all modern CUs.

You can get an insulated busbar, which is the same as the MK one, but it has a plastic shroud that clips onto it. Not sure where to get them, but I'm sure someone on here will know.

 

[securespark]

There's also this:http://www.tlc-direct.co.uk/Products/MK5567.html

Don't know on second thoughts if it's any good in your situation, though...

 

[tomathy]

Having been shown it, I'm going to purchase the replacement busbar at the same time as the RCBO. Out of curiosity I'd still be interested to know if there's anything wrong with my original method of doing this though...

 

[JohnD]

What make (and type) is your CU?

 

[tomathy]

I can't find a model or type printed anywhere on the outside of the unit. It came full of GE MCBs and RCD, so I'd guess it was GE.

 

[JohnD]

OK, thanks, don't know them, so have nothing sensible to say

Except that I think RCBOs are great.

For your situation, make sure the one you buy is one unit wide, same as an MCB (some are twice as wide)

 

[securespark]

It could well be GE or Steeple, Denmans' own brand, same as GE.

Do the breakers say Series E or Series G on them?

Click HERE

 

[tomathy]

It's this one, if that helps:

http://www.gepowercontrols.com/eu/product_portfolio/residential/consumer_units/cu_split.htm