Lighting earth issues - could I just run a fused spur from the power circuit

[thesled]

I've been looking to fit some metal light fittings, both inside and out, and I'm having problems with lighting circuit earths. Basically I don't think they exist, or at least are not reliable. It's annoying because new bits of cable seem to have been added in over time which have the earth conductor, but it often doesn't seem to go anywhere.

Access to the lighting circuits would be a nightmare, so I'm wondering if I can run fused spurs from the power circuits which would be a lot easier. I know it's not ideal but seems the least worst option. Am I restricted to a certain number of lights on each spur, or is that just determined by the fuse rating?

As far as I can work out this does not count as 'adding a new circuit' for regs purposes in England.

What do folks think ?

 

[EFLImpudence]

Access to the lighting circuits would be a nightmare, so I'm wondering if I can run fused spurs from the power circuits which would be a lot easier.

Yes, nothing wrong with doing that.

Am I restricted to a certain number of lights on each spur, or is that just determined by the fuse rating?

No limit on the number of lights. Fuse rating determined by rating/size of cable.

As far as I can work out this does not count as 'adding a new circuit' for regs purposes in England.

It could be argued both ways, so choose the way you want.

What do folks think ?

Go ahead.

 

[thesled]

Many thanks for that EFL. If I'm using standard 1.5mm T&E, I'd put in a five amp fuse I assume.

 

[Harry Bloomfield]

Many thanks for that EFL. If I'm using standard 1.5mm T&E, I'd put in a five amp fuse I assume.

Don't assume, calculate! Total up the wattage, watts/240v = amps.

 

[plugwash]

Something to think about when doing this is how easy/difficult it will be for the next guy to find the fuse. IMO to minimise confusion the fuse should be close to (or better-yet part of) the light switch. I wouldn't want to use a FCU in one room to supply lights in another.

 

[plugwash]

Don't assume, calculate! Total up the wattage, watts/240v = amps.

That's only true if the power factor is 1, which it pretty much is for incandescents but may not be true for other types of lighting.

For LEDs I would assume a power factor of 0.5. Still it would take a *lot* of domestic-sized LED lights to reach 5A.

 

[EFLImpudence]

Many thanks for that EFL. If I'm using standard 1.5mm T&E, I'd put in a five amp fuse I assume.

Yes, people will do that.

However 1.5mm² T&E has a maximum current carrying capacity of 20A - a lot of LEDs.

 

[thesled]

Something to think about when doing this is how easy/difficult it will be for the next guy to find the fuse.

Yes, absolutely agree. Hopefully it will all be set up fairly logically but in any event, a bloody big label will be going on the FCU saying 'SUPPLY FOR LIGHTS IN HALL' or somesuch.

Thanks all for thoughts on fuse and cable ratings etc, duly noted.

I should add this is in a house which had a random antique effect brass plate switch in the kitchen which was going a bit manky. I thought it was for a defunct outside light. Turned out it was for the boiler.

 

[thesled]

Yes, people will do that.

However 1.5mm² T&E has a maximum current carrying capacity of 20A - a lot of LEDs.

Yes, gone are the days when people would happily plug an iron into the light socket . . . . . . . probably ?

 

[ericmark]

Lack of earth would worry me, not because of no earth, but because the rules changed in 1966, so it points to wiring older than 1966 which means it could be rubber.

 

[Harry Bloomfield]

Lack of earth would worry me, not because of no earth, but because the rules changed in 1966, so it points to wiring older than 1966 which means it could be rubber.

I agree, it needs to be investigated. The OP said

I'm having problems with lighting circuit earths. Basically I don't think they exist, or at least are not reliable.

Not reliable, could potentially be even worse, than none at all.

 

[AndyPRK]

Go ahead that way if difficult to access light circuit.

Or you can borrow an earth off another circuit if easier. And be more logical when switching off circuits.