Adapting CU for dual tariff, am i missing anything

[MickSmith5824]

Hi all

I've been ask to change another dual tarriff consumer unit (17 useable ways) I've changed a few of these in past but choice does seem limited and always seem to pay over the odds for what it is. I am considering adapting a dual rcd FuseBox consumer unit. I'm just checking am I missing anything in plan for this? The FuseBox consumer units come with 3 neutral bars from what I remember so no problem there. So my theory is all I need to do is purchase another main switch and consumer unit cable kit BG Consumer Unit Cable Kit - https://electrical-showroom.co.uk/catalog/product/view/id/5501/s/bg-consumer-unit-cable-kit?gclid=Cj0KCQiAmL-ABhDFARIsAKywVadon4FzxhouM62TtMtRkwj9jG-WerEUWITZY3D1xmTN1iJ3U53trHMaAsjTEALw_wcB

And I'm good to go? Or am I missing anything? Been a long day : )

 

[SparkyChick]

Given it's a Fusebox board you're proposing I would use Fusebox gear only to avoid the possibility of it coming back to bite you if something did go wrong.

You should also consider adding a 4th neutral bar... you're going to have 1 for each RCD and 1 for the off-peak side which means you won't have one to use for splitting the switched neutral on the dual RCD side. You could probably get away with using the main switch terminal but again, to ensure your backside is covered I would use the cables how they are intended by adding another neutral bar.

 

[westward10]

Your link is to a BG product not FuseBox.

 

[MickSmith5824]

Given it's a Fusebox board you're proposing I would use Fusebox gear only to avoid the possibility of it coming back to bite you if something did go wrong.

You should also consider adding a 4th neutral bar... you're going to have 1 for each RCD and 1 for the off-peak side which means you won't have one to use for splitting the switched neutral on the dual RCD side. You could probably get away with using the main switch terminal but again, to ensure your backside is covered I would use the cables how they are intended by adding another neutral bar.

Thanks SparkyChick I've actually just had to take cover off my own CU to check how would all be linked together. Does look like 3 bars would do job but your right 4th would be better. Call me a numbnut but how do you actually go about fitting a 4th bar? Cheers

 

[MickSmith5824]

Your link is to a BG product not FuseBox.

Westward I've not actually been able to find any Fusebox cable kits

 

[SparkyChick]

Thanks SparkyChick I've actually just had to take cover off my own CU to check how would all be linked together. Does look like 3 bars would do job but your right 4th would be better. Call me a numbnut but how do you actually go about fitting a 4th bar? Cheers

That largely depends on the manufacturer.

Hager for example will sell you neutral bars and the clips required to mount them on the bar at the top. I've just looked on the Fusebox site and they don't appear to have anything in the way of that kind of accessory so it may be better to use another manufacturer.

My primary area of concern in suggesting this is that if you attempt to use the cables that would ordinarily be present in a split load board, one end is typically terminated in a crimp lug and the other is welded. Without the crimp lug you may struggle to properly terminate two cables in the main switch. With the lug you may find it difficult to get a good sound connection as the lugs are quite solid and cage clamps rely (to an extent) on deforming the conductors to get a solid connection. But also modifying them may also invalidate the type testing used to ensure it conforms to the required standards.

It's a tricky one and to be honest I would perhaps be inclined to use two separate boards to avoid any of this kind of nonsense.

 

[MickSmith5824]

That largely depends on the manufacturer.

Hager for example will sell you neutral bars and the clips required to mount them on the bar at the top. I've just looked on the Fusebox site and they don't appear to have anything in the way of that kind of accessory so it may be better to use another manufacturer.

My primary area of concern in suggesting this is that if you attempt to use the cables that would ordinarily be present in a split load board, one end is typically terminated in a crimp lug and the other is welded. Without the crimp lug you may struggle to properly terminate two cables in the main switch. With the lug you may find it difficult to get a good sound connection as the lugs are quite solid and cage clamps rely (to an extent) on deforming the conductors to get a solid connection. But also modifying them may also invalidate the type testing used to ensure it conforms to the required standards.

It's a tricky one and to be honest I would perhaps be inclined to use two separate boards to avoid any of this kind of nonsense.

Thanks SparkyChick really helpful. Going with the two boards might actually be a better bet the FuseBox ones are cheap enough. I'll have to check out the dimensions

 

[kropaske]

Can you use Rcbo's instead of rcd? You would only need 2 neutral bars and 2 main switches?
Also correct information on CU about isolation...

 

[MickSmith5824]

Can you use Rcbo's instead of rcd? You would only need 2 neutral bars and 2 main switches?
Also correct information on CU about isolation...

Thanks Kropaske. I'm trying to keep costs down though. The board requires 15 MCB's and 2 ways for a contactor

 

[kropaske]

Type ac rcbo is around 10 quid and type a around 14. Two rcd boards maybe more expensive than 1x rcbo board and you can do it quicker and neater