Rcd protection for domestic inatalls.

[APE37]

Hi guys. Am I right in interpreting the regs with regards to rcds that they need to be rated equal to or higher than the main supply fuse? So not to overload them? Or am I reading it wrong?
Thanks on advance.

 

[Nigel]

The main switch needs to me equal to or higher than the upstream OCPD or equal to or higher than the combined ratings of the downstream OCPD.

 

[Toneyz]

Hi guys. Am I right in interpreting the regs with regards to rcds that they need to be rated equal to or higher than the main supply fuse? So not to overload them? Or am I reading it wrong?
Thanks on advance.

That's my understanding of the regs now that's why in a split RCD consumer unit Hager are fitting 100A RCD's by default.

 

[APE37]

So for reference,
If you have a 100a main tncs supply and a 100a main switch and 2 rcds of 63 amps then this complies? I thought that the rcds would need to be 100a so to not overload them? Just looking at boards in catalogues and noticed that the boards come with 2 63a rcds or 80a rcds and couldn't see how these still comply the only board I can see comply is hager.

 

[APE37]

The trouble is only hager have done this and none of the other manufacturers seem to have followed suit. So cant see how they comply?

 

[Charlie_]

The total load must not exceed the rating of the incoming device or the assigned assembly rating (InA) whichever is the lower

 

[Baddegg]

Just fit rcbos....

 

[APE37]

But what if customer dont/want the cost of rcbos

 

[APE37]

Charlie, when you say the incoming device, do you mean the main switch?

 

[Andy78]

The trouble is only hager have done this and none of the other manufacturers seem to have followed suit. So cant see how they comply?

It's up to the installer how the install complies. A total potential load after the RCD less than the rating of the RCD will comply. If the potential load exceeds the rating of the RCD, an OCPD before the CU less than the rating of the RCD will comply.

 

[Baddegg]

In a domestic situation the customer rarely will have an opinion and some of the wholesalers own brands don’t cost much more than a split board...

 

[APE37]

With potential load can max diversity be taken into account?

 

[APE37]

Or total load of mcbs on an rcd

 

[l4urence]

But what if customer dont/want the cost of rcbos

Sell the RCBO's... we are electricians and we know what is right. Split load boards belong in the 80's. Things have changed, DC leakage current / electronic equipment. I don't compete with the flooding of the market with £60 complete (split load AC RCD's) boards. Explain the difference - give the option and if they want to fit the cheap board - find someone else to do it.

 

[l4urence]

Just fit rcbos....

if I could give one piece of advice - it would be this (type A RCD obviously)...