Electricit Issue

[baseage]

We have just moved into our house and the electricity works have been signed off. What we are finding is that when we turn on all the lights, about 5-10 min latter, the fuse box trips. I then turn off all the lights off and go back to the fuse box and turn on the tripped switch. I have also noticed the following:

1 - Some of the lights are very hot - we purchased the fixtures from B&Q
2 - Sometimes (Not that often) when i turn on the tripped switch back on, it is quiet loose and doesn’t stay up, so then i push it back up and it stay on.

Any help would be great!

 

[breezer]

the easiest way would be to take all your light fittings down and replace with a pendant lamp.

then over a course of time, put the fittings back one by one

 

[JohnD]

what is the total power used by all your lamps?

How many halogens do you have?

 

[baseage]

i will have to count them and get back to you, but if it was due to an over loaded circuit, why does it take 10 mins for it to trip?

 

[baseage]

in terms of halogens, we dont have any. Just single lights and a few combo ones

 

[Spark123]

It can take that amount of time for the thermal part of the MCB to warm up to the point that it trips. As JohnD asks, what is the load on the circuit?

 

[bernardgreen]

Some MCBs have two means of tripping. A magnetic mechanism that trips almost immediately on large overloads (such as short circuits) and a slow acting thermal mechanism where the time to trip depends on the amount of overload. You may have one of those with a slight overload activating the thermal mechanism.

Or when one of your lights gets hot expansion of metal against heat damaged cable with exposed conductors causes a short circuit.

edit <<too slow typing >>

 

[Softus]

...why does it take 10 mins for it to trip?

Because that's how those protective devices are designed to operate. The greater the overload, the less time before they trip, and there's a threshold of overload below which they will, effectively, never trip.

 

[baseage]

the capacity is 1200 and currentley we have 1000 being used, so we are not over capacity, so i would say that the overload doesnt apply?

 

[Softus]

Is it possible that you have something spurred from that lighting circuit?

Alarm? Doorbell? Pond pump? Boiler/heating?

One way to be sure would be to measure the current using a clamp meter.

And when you say "capacity", how have you calculated this? What's written on the breaker that's tripping?

 

[baseage]

To be honest i think it may be the heating issue of the fixtures. The reason why i say this is that we have changed a few of the lights from a multi bulb to a sing bulb and the tripping has not been so frequent. In addition to this, the ones that are still up are very hot to touch. What do people think? Also, why would the fixture get so hot??

 

[Softus]

To be honest i think it may be the heating issue of the fixtures.

That seems rather unlikely.

...we have changed a few of the lights from a multi bulb to a sing bulb and the tripping has not been so frequent.

If you've removed some bulbs then you've reduced the overload.

In addition to this, the ones that are still up are very hot to touch. What do people think?

Personally I wouldn't go touching the fitting when the bulb is on, or has recently been on.

Also, why would the fixture get so hot??

Light bulbs generate more heat than light.

Would it be possible for you to give some more hard facts about the bulbs?

For example, you say that the load was 1000 (Watts I presume), which would be ten 100W bulbs, or a mixture of twenty 60W and 40W bulbs. This seems like a lot for one lighting circuit.

Also, what is written on the breaker that's been tripping?

PS Yes I know that they're called lamps, but lets keep it real.

 

[baseage]

i will get back to you re the exact power. with regards to the heating, it is the actual fixtures that i am talking about and not the globe. does this help?

 

[Softus]

i will get back to you re the exact power. with regards to the heating, it is the actual fixtures that i am talking about and not the globe. does this help?

If I asked you what's written on the MCB, and you tell me that the fixtures are getting hot, then no - that doesn't "help".

 

[baseage]

sorry i was making that commement because of what bernardgreen said -

Or when one of your lights gets hot expansion of metal against heat damaged cable with exposed conductors causes a short circuit.

will get that info and get back to you