RCBOs on an RCD'd mainswitch

[DomB]

Hi,

If I had a CU with an RCD'd main switch and put in a new circuit on an RCBO, would the RCBO always be the first to trip should there be a fault on that circuit?

Thanks!

 

[nickblake]

If your customer want RCBO's do as short circuit says or to reduce the costs a little buy a split load board and go half half

 

[DomB]

Ah that's brilliant - thanks, you pointed me right to it - I see Wylex do a Dual RCD Split load high integrity board which would allow me to put in the RCBOs for those HI circuits.. Perfect.

 

[1shortcircuit]

He's calling for RCBOs for his alarm & heating circuits.

I should read more carefully in future

:thumbsup

 

[DomB]

Thanks Nickblake, I was looking for a way of splitting out the circuits across two RCDs yet still have High Integrity circuits. Wylex's "HIGH INTEGRITY DUAL RCD SPLIT LOAD UNITS" look to be the go

 

[nickblake]

if you get a 15 way hi integrety wylex board they supply bus bars you can cut so you could have a board 5 x 5 x 5 being 5 rcbo's then 2 lots of 5 MCB's protected by 2 RCD's , but you configuer them as you want

 

[Deleted member 19807]

just strick the RCBO's between the main switch and the 1st rcd.

edit to say, i prefer somokes on a lighting circuit

 

[1shortcircuit]

Ah that's brilliant - thanks, you pointed me right to it - I see Wylex do a Dual RCD Split load high integrity board which would allow me to put in the RCBOs for those HI circuits.. Perfect.

DomB, If you search through some of my created threads you will see that I too was assisted by the forum regarding a similar matter so I am just passing on assistance that I received.

I would mention to the customer that there will be a significant increase in price though due to needing the High Integrity board and the RCBO's. Off of the top of my head that is going to be an additional 100 quid or there abouts depending on where you obtain your materials and how good a discount you qualify for :thumbsup

 

[Short Circuit]

1shortcirucit is right, change the main switch to a 100a isolator, then RCBO for every thing - the customer cant have it both ways! The other option is a high integrity board with the two sets of RCDs and then the RCBO's on the unprotected side

 

[Short Circuit]

just seen the last posts about the high integrity board, i didnt see the second page - soz

 

[topquark]

Why buy a dual RCD board if you are going to add RCBO's? Just buy a main switch board, one RCD and RCBO's then you can mix MCB's and RCBO's on the first neutral and RCD protect the other neutral.

 

[Deleted member 19807]

As its TT there is a school of thought that we need to provide 2 pole isolation as neutral current can be high. perhaps a 100mA s type as a main switch would still be a good idea.

 

[1shortcircuit]

hifly, thanks for the link in your signature. Made me chuckle

Sorry to take this off topic

 

[topquark]

As its TT there is a school of thought that we need to provide 2 pole isolation as neutral current can be high. perhaps a 100mA s type as a main switch would still be a good idea.

Sounds like a plan!

 

[1shortcircuit]

we need to provide 2 pole isolation

So a 100A main switch is not 2 pole?

 

[topquark]

So a 100A main switch is not 2 pole?

They are. Hifly (I think) is talking about in the event of a residual current fault.