Lighting Circuit Topology

[rowan.bradley]

Does a lighting circuit have to be linear, with just two ends, or can I have T's and branches with multiple ends? I.e. when I am adding a new light, do I have to find one of the ends of the existing cuircuit to extend from, or can I just cut the exisiting circuit, add a junction box and T off?

Thank you - Rowan

 

[Fleeting]

No you can "T" off but if using a junction box which will be concealed then it needs to be maintenance free. Assuming this is a dwelling it will also need 30ma additional RCD protection.

 

[rowan.bradley]

Thank you for that. What is the difference between a maintenance free junction box, and one that is not maintenance free? How do I tell whether the MK junction boxes that I have just bought are maintenence free or not? If the junction box is in the roof space, does that count as "concealed", or not?

My consumer unit has a 30mA RCD in it, but the lighting circuits are not in the protected part of the CU? What's the best way out of this? Move the lighting circuit to the protected part of the box (which will involve moving a lot of stuff around becuase the box is completely full)? Add another RDC (again difficult because the box is full). Change the MCB for the lighting circuit to an RCBO? Fit an in-line RCD? Or anything else?

Thank you - Rowan

 

[binky]

Ts and branches are normal for lighting ccts. Pendants are great points for adding a cable

 

[Fleeting]

If the roof space is readily accessible then a standard junction box is fine. As for RCD protection I can't give advice on altering your consumer unit that would be inappropriate.