More than one RCD?

[geordie169]

Hi,

Could someone clear up whether it is beneficial or not to have more than 1 RCD device?

I have a 100AMP 100ma RCD fitted between the meter and the CU, I am going to be upgrading the CU for future expansion and am wondering if there is any point in gettinga split load unit with built in RCD as effectively the whole circuit will still remain on the existing RCD.

Would I be better swapping the 100ma RCD for a double pole isolator and get a split load CU with in-built RCD?

 

[andy]

if you have an earth rod then the 100ma RCD MUST stay. other earthing then you cou8ld change it for a isolator and have a split load board

 

[Damocles]

That depends why you have a 100mA rcd in the first place. It is possibly there because the earth connection is too poor to rely on it for safety. Hence 100mA RCD are fitted covering all circuits. This is less sensitive than the standard 30mA type, so there is less chance of nuisance tripping. But it is beneficial to have a 30mA RCD on the sockets as well, hence a split CU remains a good idea. The 100mA should also be a time delayed type, to ensure that the 30mA trips faster.

 

[Lectrician]

Does your maoin earth from the CU go into the Elec Boards Fuse adjacent to the meter??

 

[geordie169]

Does your maoin earth from the CU go into the Elec Boards Fuse adjacent to the meter??

The servicefuse is not located near my meter but the earth does run along side the main live/neutral feeds to where the service fuse is where it joins it's own termination.