Connecting a new light direct into a light circuit at the CU

MrS

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There are obviously better ways of doing things and more costly ways of doing things but im interested to know if these things can be done safely and within regulations if needs be. The decoration of a house can also severely limit what you can and cant do.

1. A light under the stairs needs adding and access is difficult and it would be a big job to get a lighting cable from an existing light. If the consumer unit is very near the stairs, would it be ok to run a new cable from the consumer unit to the light but put the new cable into the same connection on the consumer unit as the current lighting circuit?

This would result in the downstairs lighting circuit being on a 6A mcb and the new light also being directly connected to the same 6A mcb. Assuming it didn’t exceed the load would this be an acceptable way of adding a new light if there wasn’t really another option without causing major work?


2. A new outside light over the front door needs adding. The easiest, quickest and most cost effective way would be to add a cable direct from the 6A lighting circuit mcb on the consumer unit leading into a FCU and then onto the outside light. Would this be ok to do?


3. If your consumer unit was full and you needed another connection for something, would it be ok to take off the upstairs lights from their own circuit on the CU and put them into the mcb of the downstairs circuit in the mcb in the CU? This would be assuming that the length cable is still within the voltdrop regulations of 9.2v and that it doesn’t exceed the load of the current mcb.


4. The same situation as no1. Instead, add a FSU on the socket ring main and then go to the light and light switch under the stairs. I know this is an option but would it cause a problem if the ring circuit is on an RCD and you add a light to it, or would it not cause a problem because the light will hardly ever be used anyway.

The same question also relates to an outside light, will this cause a problem if it is run from an FSU on a ring circuit that is protected with an RCD.
 
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There are obviously better ways of doing things and more costly ways of doing things but im interested to know if these things can be done safely and within regulations if needs be. The decoration of a house can also severely limit what you can and cant do.

sometimes damaged has to be done...

1. A light under the stairs needs adding and access is difficult and it would be a big job to get a lighting cable from an existing light. If the consumer unit is very near the stairs, would it be ok to run a new cable from the consumer unit to the light but put the new cable into the same connection on the consumer unit as the current lighting circuit?

you can spur from a ciruit at any point, including CU

This would result in the downstairs lighting circuit being on a 6A mcb and the new light also being directly connected to the same 6A mcb. Assuming it didn’t exceed the load would this be an acceptable way of adding a new light if there wasn’t really another option without causing major work?
see above....

2. A new outside light over the front door needs adding. The easiest, quickest and most cost effective way would be to add a cable direct from the 6A lighting circuit mcb on the consumer unit leading into a FCU and then onto the outside light. Would this be ok to do?scrap the FCU. just make sure if has a DP switch if the circuit is RCD protected


3. If your consumer unit was full and you needed another connection for something, would it be ok to take off the upstairs lights from their own circuit on the CU and put them into the mcb of the downstairs circuit in the mcb in the CU? This would be assuming that the length cable is still within the voltdrop regulations of 9.2v and that it doesn’t exceed the load of the current mcb.
change fuse/MCB for 1 light circuit to 16/15A. above CU have 2 FCUs with 5A fuses in. have 1 for up lights and 1 for down lights. and you now have a spare space in CU

4. The same situation as no1. Instead, add a FSU on the socket ring main and then go to the light and light switch under the stairs. I know this is an option but would it cause a problem if the ring circuit is on an RCD and you add a light to it, or would it not cause a problem because the light will hardly ever be used anyway.
see answer above about DP switch
The same question also relates to an outside light, will this cause a problem if it is run from an FSU on a ring circuit that is protected with an RCD.

why all the questions? these seem more like what you would be asked at college. you should ask your lecturer to explain stuff in more detail. thats what he is there for
 
Thanks andy, the answer to number 3 is a good one that i hadnt thought of.
 
What's this got to do with reading up on BS 7671 prior to taking a 2381 course?

Are you sure you're not doing some kind of installation work for which you are not yet fully competent?
 
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Mr.S. has blatently just bought a copy of the OSG and is now trying to work as an electrician.
 

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