interconnected lighting

[daiplayer]

Hi all

I have recieved a q from a mate that i cant answer.

He replaced his own consumer unit , ( from a rewireable fuse type ) to a split rcd board.

When he powered it up it tripped the rcd. I visited him to have a look and found that when the previous 'electrician' Had installed a two lighting for the landing light. He took the perm from the downstairs lighting ......and his nuetral was connected to the upstairs lighting....

To get his lighting to work i placed both his lighting mcb's on the same rcd ( same current on live and nuetral for the rcd) ...and therefore no trip.

Any comments on if this is acceptable ? ...would elecsa/nic etc deem this to be unacceptable in an assessment ? would there be any technical issues with the operation of the rcd in the case of a fualt ?

Thanks all :-D

 

[telectrix]

common situation. whilst not ideal ( as you can isolate the upstairs and the landing light will still be live ). it is called " borrowed neutral " and a note should be fixed to the CU. ideally, the landing light should be fed both L and N from upstairs. this would entail running a conductor from the switch downstairs to upstairs, or, better still, a 3core.

 

[daiplayer]

I told my mate the same, but he seems to not want to run the cable ?? ....

Is there any repurcussions to just moving the breaker ? if fit a notice is this this acceptable in regards to a installation certificate and nic/elecsa assessments ( just for future knowledge)

Thanks

 

[londonlec]

If both the Line conductors are in the top of the same MCB then its no longer a borrowed neutral.

However in the event of a fault you have NO lighting at all. You could possibly fit some emergency light fittings.

 

[londonlec]

Double post

 

[nickblake]

IT not hard to drop a cable down to the ground floor lighting circuit to supply the neutral to the landing light and JB the cable at the first floor , best option in my opinion , its just amazing how often this problem crops up

 

[telectrix]

a simple alternative to save chasing cables would be to disconnect the downstairs switch, feed a L to the landing light from the upstairs, then replace the upstairs 2way switch with a remote control switch.