halogen lights and fuse


My friend has 13 number halogen 50 watt light bulbs in her kitchen ceiling and on 3 occasions now the 5 amp fuse has blown. The fuse box is an old one with fuse wire and no cartridges. I just replaced a fuse again to-day. I suspect that the load is just too much for the 5 amp fuse wire and am wondering about replacing it with 10 amp. Has anyone any ideas on this and is it likely to be safe enough with a 10 amp fuse? Thank you.
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I am not an electrician, but assuming they are 240v then the current drawn should be about 3 amps.
We have 12v halogens in the kitchen, and they do seem to make the RCD very twitchy - 2-3 times a week it has to be reset after switching on the lights. The usual problem is one of the bulbs blowing.
I wouldn't replace with a 10amp fuse until I had satisfied myself there were no other issues - fuses are there for protection after all!!
SalesGuy
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There is little or no difference in the current passing through the fuse wire whether or not you use 12 volt or 230 volt 50 watt lights.

You have to change a 12v halogen lamp 2-3 times a week?
Adam
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13 * 50 watt gives a total load of 650 watts. At 230 volts this gives a current of 2.83 amps and will not blow 5 amp fuse wire. What other lights are on the circuit with the halogens? (outside 500W floodlights maybe) Add the total wattage of all the light on this circuit and divide by 230 to get the current that is drawn.
I would not change the fuse wire to 10 amps without testing the circuit and knowing a little about its installation.
Adam
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Stewart wrote:

I am assuming these are 240v halogen lamps and not 12 volt ones.
Does the fuse blow when switching the lights on, or when a lamp fails, or just at random?
I suspect the first - in which case I would be thinking of replacing the on/off switch with a soft-start dimmer, suitable for halogen lighting of this total power. That should save the fuse blowing, lengthen the lamp life expectancy and also reduce the electric bill as the lamps, at 650watts, possibly won't need to be on full all that often.
As to changing the fuse for one of twice the current rating, that really does depend on the wiring. I'd go for the dimmer. If the replacement fuse wire is old )and corroded), you may find just buying a new card of fuse wire does the trick.
If the fuse is blowing concurrently with a lamp failing, then a soft start dimmer may become an expensive fuse.
--
Sue

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Thanks all. The circuit is on 230 volts and as commented I suspect that the fuses are blowing when she switches on, I also think there may be another light in a boiler room on the same circuit so I shall have to check that. The halogen lights were fitted by a "homer" about a year ago and he just used the existing fuse board that served 2 strip lights and one cupboard light. As you say it could be risky, especially in an old house to change the fuse to a 10 amp. I think my friend does not want to call in the electricity company or an approved electrician lest she is told that the whole house will have to be rewired. When I went to look for the fuse box to-day I actually found 4 of them, all with the old type fuse wire.

ceiling <snip> <snip>
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Not an expert, but wouldnt it also matter what else was connected to the ring....all downstairs lights for instance??
Ken

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Ken wrote:

The Op asked about changing the fuse from 5A to 10A. I wrote, " As to changing the fuse for one of twice the current rating, that really does depend on the wiring."
Which is, as you say, because what else is wired to that fused circuit would matter.
However, failing lamps can blow fuses. ISTR reading it is because, as the lamp wire breaks an arc is formed which vaporises some filament wire which then shorts out more of the filament, producing more vapourised metal and thus allowing even more current to flow - until either the arc becomes too big to sustain in the near vacuum or the fuse blows..
Sue

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If there is too much load on the circuit, then the circuit should be split into 2 smaller circuits, each with a 5a fuse or better still, RCD. The lighting circuit should not have a 10a fuse or RCD and to do so would probably be in breach of regulations. I would replace the fuse with a 5a RCD before undertaking the job of splitting the lighting circuit. If you go as far as splitting the lighting circuit, then it would be as well to have a full rewire.

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a.n.other wrote:

Do you mean 5A MCB?
Sue

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That is a good idea, the lights are controlled by 2 separate switches, half from her rear door and the other half (6 lights) from the hallway door. It would not be too difficult to split the wiring and insert an extra fuse. Thank again.

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When I went to look for the fuse box to-day I actually found 4 of them, all

What is wrong with fuse wire? The 16th edition IEE regs still accepts it as a viable means of protection to cables.
Adam
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