downstairs sockets tripping downstairs lights

techmob

Hi

all of a sudden when we use anything in the downstairs sockets it trips the down stairs lights off( the RCD)

i don't understand how the downstairs sockets can trip the downstairs lights as it is supposed to be on a different RCD

RCD1
downstairs lights
upstairs sockets

RCD2
upstairs lights
down stairs sockets

how would having anything through the down stairs sockets trip the downstairs lights?

i did an earth Test with the test button on the CU and it didn't work with the RCD with the downstairs sockets.

macman

Are the downstairs lights ceiling lights run off a 5A lighting circuit, or are they wall lights, which might be spurred off the downstairs ring main via FCU's fused down to 5A?
Turn off the downstairs ring main via the circuit MCB and see.

techmob

i will have to keep reading that to see if it makes sense to me heh.

how would i turn off the dowstairs ring main via the circuit mcb?

the downstairs lights are all wall lights, except the front room which has two wall lights and a pendant. however the hall way is a 2 way with upstairs landing.

not sure if that information is relevant to you

macman

Just flip the individual ring main MCB rather than the RCD.
As I thought-wall lights. They're probably controlled via switched FCU's down near skirting board level-look below them and see (i.e. they're fed from your downstairs 32A ring main).
You should check that these FCU's are fused down to 5A and not using 13A fuses.

techmob

so the wall lights in the front room might be controlled via a switched FCU?

so if i follow/trace the cable going to the wall lights and see where they go?

macman

If visible, yes. Probably chased into the walls from a 13A socket nearby, along to an FCU and then straight up to the light. But if you just turn off the ring main and the lights go out, you'll know for sure without any need to trace cables.
It's usually easier with wall lights than chasing down from the ceiling, and avoids removing the upstairs floorboards.

techmob

sorry i meant all lights are ceiling lights except the front room which has a ceiling and wall lights

techmob

floor boards are already up in places so i can see, follow the cables.

the cables don't go to a socket as far as i know. they are ran all the way back but i need to find where. will check tomorrow

vaio

techmob wrote: »

.......i did an earth Test with the test button on the CU and it didn't work with the RCD with the downstairs sockets.

Faulty rcd so change that as a starting point. Then I'd check for wrongly connected neutral

macman

techmob wrote: »

floor boards are already up in places so i can see, follow the cables.

the cables don't go to a socket as far as i know. they are ran all the way back but i need to find where. will check tomorrow

It's not necessary. If you trip the individual circuit switches it will be instantly obvious which light is on which circuit.

techmob

am i right by thinking that the problem is not with the sockets even though it happens when i use something in the downstairs sockets it does not trip the RCD that has the downstairs switches it however trips the the RCD with the downstairs lights one instead. would this mean that the fault is most likely something to do with the down stairs lights?

thanks