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
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!!
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.
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.
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
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
When I went to look for the fuse box to-day I actually found 4 of them, all
with the old type fuse wire.
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
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..
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
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.
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