Two lighting circuits - One Breaker

[The_Scotty]

I was having a look inside the CU at my grans flat (one level).

All wiring was redone during extensive renovations in the mid 90's.

She has one breaker for all her lights with two wires (red) in it.

Got me thinking. Would this be two seperate lighting circuits into the breaker. And if so, is this common place and safe?

She has 6 rooms that have lights in them (all pendants)

One reason I could think of is that routes overhead for lighting cable might have been made difficult by steel beams and the electricians may have just taken one feed one way and another in the other direction (CU is in centre of flat)

 

[SeanT]

Normal, and safe (provided of course it is all wired correctly / usual caveats) - there are not two separate "lighting circuits", just two wires making up the full lighting circuit into the breaker - best make sure that the neutrals are both in there too though....

 

[The_Scotty]

Thanks Sean. Everything is present and looks correct (Earth, Neutrals) all the lives look neatly wired and everything works as it should.

Just thought I'd ask

 

[Taylortwocities]

As Sean says, its quite normal.

Strictly speaking, the regs say that every circuit should be on its own breaker. In real life sometimes it just cant..

 

[GaryMo]

As Sean says, its quite normal.

Strictly speaking, the regs say that every circuit should be on its own breaker. In real life sometimes it just cant..

Would the same be said for a 2.5mm radial feeding one socket or fused spur leaving 2 x 2.5mm conductors which form a ring final from a B32 MCB?
It's no different from a spur from any other socket on the ring final.

Definitions:

Circuit - An assembly of electrical equipment supplied from the same origin and protected against overcurrent by the same protective device(s).

I see that example as no different to two 1.5mm conductors leaving a B10 MCB feeding lighting. Both 1.5mm conductors form one circuit.

 

[SeanT]

As above, it is only one circuit, the same as two radials off one breaker is really only one circuit.

 

[Space cat]

The only problem is that breakers have a habit of tripping when a bulb blows - and then all the lights will go out. This won't be so bad if she has a few lamps plugged into wall sockets. Plan ahead. It's dark outside and the breaker has just tripped. Will your gran be able to find her way to the CU and reset it?

 

[333rocky333]

Would the same be said for a 2.5mm radial feeding one socket or fused spur leaving 2 x 2.5mm conductors which form a ring final from a B32 MCB?

That used to be shown in all the ring wiring diagrams as normal as a way to spur off.

for some reason its not shown in the iee guide to the building regs
They do show Two lighting circuits bunched in a mcb
on top of that they seem to be the up an down lights for the whole building.
Not really good advise for the iee to show someone, i would have thought

 

[333rocky333]

As above, it is only one circuit, the same as two radials off one breaker is really only one circuit.

I genuinely dont understand this one, and i have read it before elsewhere.

Why is it that when two what i call lighting circuits when put in one mcb ,
Why do they become One circuit, as opposed to two bunched circuits
I appreciate the mcb will do both and the N and E would most likely be bunched also

So would it then be ok for two rings to be done like that.
I am not critisising what you say I genuingly would like to know
thanks.

 

[The_Scotty]

The only problem is that breakers have a habit of tripping when a bulb blows - and then all the lights will go out. This won't be so bad if she has a few lamps plugged into wall sockets. Plan ahead. It's dark outside and the breaker has just tripped. Will your gran be able to find her way to the CU and reset it?

No probs there mate, cheers.

She rarely has the lights on when she is in on her own. She prefers lamps plugged into the sockets.

Good point tho

 

[securespark]

Going back to the original post, are you sure they are both internal lighting?

One could be doorbell or BA or external lighting?

 

[The_Scotty]

SecureSpark, No idea TBH. Could be the door bell.

I just seen two wires at the breaker labeled lights and wondered whether this was normal practice (if it was two lighting radials)