Installing RCBOs

[ban-all-sheds]

Ah - how easy it is to say "individual RCBOs are the way to go"...

Assuming you can't get a DP busbar then you've got no choice for the neutral feed to each one except cables from a N bar in the CU.

But what would be your preference for the line supply when installing 2-module DP ones - cut off every other bus-bar prong, or use distribution block(s) and a cable to each one?

 

[RF Lighting]

I'm not sure what you mean?

I've only ever used Merlin Gerin DP RCBOs. The base of these looks like the base of a DP main switch. i.e. two terminal holes 17.5mm apart. The hole on the left is the line supply to the device, and the hole on the right is just a hole. This allows the busbar prong to stay in place, but it is not actually connected to anything.

The neutral is supplied by a 'flying' lead as per a SP module.

 

[NotHimAgain]

i take it that this is for your made up board.

It depends on which make and model of kit you use - M & G have units as RF Lighting describes above, but they also do neutral kits for 4 pole outgoing mcbs and 2 pole RCBOs which are actually a 2 pole mcb with a further 2 pole trip unit attached.

MEM can provide an RCD trip module for most of their range of mcbs, including the SPSN devices.

Hager seem to do a single module SPSN RCBO, but I can't actually find it

Beware though BAS - I once spent a long time designing a special system for a farm using the M & G kit, only to find that when I tried to order it that they didn't actually appear to stock some of it.

 

[RF Lighting]

Hager seem to do a single module SPSN RCBO, but I can't actually find it

They do a SPSN MCB in one module.

Their SPSN RCBO is two mods. It can also be used in CUs without adapting the busbar.

(There is an all terminal version without the neutral fly lead which can not be used with a standard busbar)

 

[NoPoke]

You could always use a three phase busbar and remove/ignore one of the phases. This does mean that you have to use blanks between the breakers to pad them out.

I would cut the unused prongs on a single phase bus bar only if there is no risk of damage to the neutral wires that may have to be routed very close to the phase bar.

FWIW Asea Brown Boveri make 2phase busbars for miniature circuit breakers.