2 lighting cicuits in 1 CU fuse

[DJM]

As a result of finding some unusual aspects of a lighting cicuit (see other thread for ugly pics) I had to remove the fuse for safety and I noticed that there were in fact 2 lighting circuits from this fuse.

I Initially thought that maybe somebody had set the lighting up as a ring, but having traced the circuits as necessary for the remedial work from other thread, it's definitely not a ring.

Neither are particularly large (length or load) and added together fall happily within the fuse rating, so I can't understand why it's been done this way, but I assume this is not best practice.

Both circuits are 1.5mm2 and in junction box formation (rather than loop in) and connected to a pretty old MEM CU and will in the not too far distant future be moved to a new CU. So would I be better asking sparks to seperate into two circuits in new CU or tag one on the end of the other to form a single circuit?

 

[sajeel]

Personally its better to have 2 separate circuits. This is easier to label and identify in the event of fault. 2 x 6A mcb should be sufficient for each circuit, but should be confirmed by calculation from an electrician.

Hope this helps.

 

[TicklyT]

Sometimes lighting circuits are installed with two cables at the CU because that's a logical way to cable them.

In our house, the CU is in the middle of the house, so there's two cables feeding the downstairs lighting circuit, one feeding lights 'north' of the CU, and t'other heading 'south'.