CU split board - 30ma / 100ma , problem or not a problem?

[LukeScotty]

been looking at a cu today, sum of us had a discussion about rcbo's n rcd's.

Righty, what we have is a split board, 30ma rcd on one side, and 100ma s type main switch on the other. Got Cb's on the 30ma side which is fine, but on the 100ma side theres 2 x 30ma rcbo's. Now does this contravy any regs in the 17th having rcds inline with each other, is there any problems with this set up or is it fine? you thoughts please

regards luke

 

[Spudnik]

No problem as far as i can see as the 30ma RCBO's will/should operate before the 100ma main.

However, if the CU s being changed then you can opt for (if you can find one) an all insulated or class II insulated DB with 100A main switch and split load with 2 30ma.

Make sense?

 

[WarrenG]

Luke the 2 30mA RCBO's although sittng side by side on the 100mA S type side are protecting the individual circuits and like Jason said will operate before the 100mA upstream. Problem would be if the 100mA were to be replaced with only a 30mA RCD. You would have no discrimination and no time delay.

 

[trebor]

been looking at a cu today, sum of us had a discussion about rcbo's n rcd's.

Righty, what we have is a split board, 30ma rcd on one side, and 100ma s type main switch on the other. Got Cb's on the 30ma side which is fine, but on the 100ma side theres 2 x 30ma rcbo's. Now does this contravy any regs in the 17th having rcds inline with each other, is there any problems with this set up or is it fine? you thoughts please

regards luke

cant see a problem as you have surely achieved discrimination of rcd`s in series exactly as required by the regs