17th edition CU's

adam.h · Jun 29, 2009

Bought a ccu a while back to replace the old one we have and was going to do it at the last moment as I will need building control to sign off all the other work as well. Everyting was supposed to be finished a few weeks ago but one delay has let to another and it's... well taking too long. Anyhoo, the cu I bought was not a 17th edition one. As the 17th is in full force on july 1st I will need to add another RCD.

What would the configeration be for a 17th edition cu, all d/s circuits on one rcd and all u/s on the other but swapping the lights so u/s lights are one d/s sockets and and d/s lights are on u/s sockets.

If everyting is on RCD then wont you get a lot of neucense tripping from things like washing machine, irons, heaters etc?

Staffie · Jun 29, 2009

Just share the circuits between the two RCD's, ie; d/s ring on the one side and u/s on the other, same goes for the lighting. This will allow there to be power/lighting in at least half of the dwellings should one of the RCD's trip.

Appliances you mentioned don't usually trip RCD's unless they have a fault or there is a fault on the circuit suppling it etc!

adam.h · Jun 29, 2009

ok thanks. But the way things are wired is the loft is all taken from the u/s and not on its own breakers.
I guess that I'm just worring that all the appliences may all add up and keep tripping the rcd

I was thinkign of having lights swapped so at least if one of the rcds trip then either sockets or lights will work on that floor or is that not really a good way of doing things?

Staffie · Jun 30, 2009

adam.h said:
ok thanks. But the way things are wired is the loft is all taken from the u/s and not on its own breakers.
I guess that I'm just worring that all the appliences may all add up and keep tripping the rcd

I was thinkign of having lights swapped so at least if one of the rcds trip then either sockets or lights will work on that floor or is that not really a good way of doing things?

It's not unusual for some dwellings, especially older one's to have the u/s and d/s ring as one circuit, the same can be said for the lighting. Seperating them may involve a lot of disturbance, and in my opinion isn't worth the hassle!

If you're worried about the load being to high and tripping the RCD (unlikely), you may want to opt for 80A RCD's if you haven't already? I personally never use 63's!