Repairing a lighting circuit - HELP!

[nigel RA]

My house has a loft conversion. The loft has its own fuse box with trip fuses - one each for the lighting and plug socket circuits.

Half the lights on the floor below have stopped working. My electrician has lifted the floor as much as is possible and thinks the fault lies under the top bathroom floor. He says the loft converters have trapped cables or the older connectors have come loose? He has isolated the half of the circuit that does not work. He intends to run a new supply to the other end of the middle floor lighting circuit and thus isolate the damaged area. To achieve this he will have to run a new supply in a channel cut across the newly decorated stairwell. The middle floor light will then have two circuits joied together instead of one single loop.

He has temporarily reconnected power to the damaged light circuit by plugging a 5amp fused plug into the loft conversion's plug circuit.

To avoid massive upheaval and expensive redecoration I would like him to connect a 15amp spur from the loft conversion plug circuit and run the half of the middle floor lights from this supply instead.

He says this would work but prefers the correct way of doing it.
He also says that running a light circuit off a 15 amp fused spur like this can lead to the light bulbs popping more often.

1. Is the 15amp spurred off the 30 amp circuit a viable solution?
2.Is he right about the popping lights? Seems odd to me.

Advice greatly appreciated to avoid MASSIVE redec and muck and angry wife!

 

[davy_owen_88]

1) Why do you need 15A for lights? What are you doing in your new loft conversion?

2) Fuse ratings don't cause lamps to blow, rappers do. Sorry, I mean overheating, carp lamps, loose connections and voltage fluctuations cause premature lamp failure.

 

[nigel RA]

Sorry - the fuse box in the loft shows 10amp and 32 amp trip switches.

I thought lighting circuits were 15amp - obvioulsy not! As you can see, I DO need advice!

 

[nigel RA]

Perhaps what I should have asked is 'can I run the ceiling lights in the middle floor of a house with a loft conversion off a spur from the plug circuit in the floor above to avoid huge re-wiring mess and expense?

 

[davy_owen_88]

Yes, it's not the best way of doing things but it can be done.

 

[nigel RA]

Thanks for that. Greatly appreciated. My wife will be delighted and so will my wallet!!

Why does my electrician think that this might cause more bulbs to 'pop' on the lighting circuit?

What are the pitfalls of the fused spur solution - if any. I do understand that a professional would want to wire it up properly but besides that are there any pitfalls?

 

[davy_owen_88]

If you have high loads for lighting then that will of course be taken off your 32A limit for the socket circuits. Since you have a 10A lighting circuit would I be right in assuming your house is downlight central?

If you socket circuit trips the RCD due to earth fault or the MCB due to overload/short circuit then your lights will go off too - this can be dangerous if you are for example up a ladder, walking down stairs etc.

I have no idea why your electrician thinks a larger fuse will cause lamps to fail more often, perhaps you should find another electrician or ask him to explain it to you.

 

[nigel RA]

The loft has a bathroom with shaver, two sets of miiror lights and 8 x 50w low voltage ceiling downlights. The rest of the loft is a large, L shaped open plan area with 14 x 50 w 240v spots, 2 x 150 hanging lights and a ceiling fan. There are also two strip lights in the attic voids. There are 2 x 10 amp trip switches and 1 x 32 amp for the plug sockets on the loft consumer/unit fuse box.

The middle floor lighting circuit, which the spur would run, has a track with 6 x50w bulbs, 2 x 150w lights, 1 x chandelier with 5 x 100w halogen lamps, 2 x chandelier lights total 7 x 60w = 1520w total?

The loft plugs only 3 run floor 50w lamps and a small stereo.

I take the point about the lights going off if the floor circuit tripped. I had not thought of that.

 

[Steve]

What rooms are these high-wattage lights in??? Bedrooms? Why do you need 500 watts of halogen light in one room?

 

[nigel RA]

The 5x100w halogens are in a chandelier made of dark decorative glass 'cups'. Looks v. pretty as it throws coloured light around the place - when on - which is not often!