Light fitting keeps tripping fuse sometimes

[wigwam12]

Bit confused about this one.
Brought a fancy light across from old house to new one and had it put up in reception room.
Sometimes it comes on fine but other times when you try to turn it on it trips the fuse for lights on its circuit.
Things is when I flick the switch back up on the fuse box it and all the other lights do come on.
Sometimes it comes on just fine - I have just not been able to identify a pattern.
Builder yesterday had the floorboard up in the room above to look at the wiring and it is all fine.
Took it down and put a temp ceiling rose up and that it absolutely fine.

Where would I get started with trying to work out that is the problem?

 

[PrenticeBoyofDerry]

Took it down and put a temp ceiling rose up and that it absolutely fine.
Where would I get started with trying to work out that is the problem?

I think you already have, as it could be that the fancy light fitting that has a fault.
Unless it was fitted incorrectly and when replacing with rose this cleared the fault.
So you could try put it back up again, making sure all connections a correct and secure.
Does the fancy light have integral transformer?

 

[ericmark]

There are many reasons why some thing can cause protective devices to remove the power so some questions which may help work out the problem.

* - What type of protective device is it. The little switch like things in the consumer unit (new name for fuse box) can be MCB's or RCBO's the latter has a RCD built it so will somewhere have a test button on it. The reason for question is some lamp types can cause spikes which could trip RCD's when really there is not fault. But no point going into that until you answer.

* - Next MCB's and RCBO's have a marking like B6 or C6 etc the B - D tells us what magnetic bit is used and the 6 - 10 - 16 tells us the amps for thermal bit this may help if we know what is fitted.

* - The lamp type will also help. Compact Florescent Unit (FCU), LED, or Tungsten Halogen if the latter what voltage 230v (Low Voltage) or 12v (Extra Low Voltage).

* - Switch type plane on/off or dimmer.

* - Be honest what have you done. Did you or friend fit it or was it fitted by an electrician? If mistakes have been made maybe we can work out what mistake. Connected to this does it matter what way light switch is when you try to switch it back on. It is common for DIY people to get a black switch return wire mixed up with a neutral.

 

[wigwam12]

Thanks

The light was put up by my builder who does all the work for me.
He was the one who put it up at the last house where it worked fine for years, took it down and then put it up again here (as well as taking it down and swapping out for a ceiling rose).
It is one of those with lots of G4 bulbs (about 20 although about 5 are blown and have been for a little while - none blown new) so I am assuming it does have an intergral transformer but if so it is not visible as the internal wiring is protected behind a thin foil-esque cover with the connection to the house wiring coming out from it.

The consumer unit has not of circuit breakers and also RCD switches and it is just the circuit breaker to this circuit that trips.

In essense I want to try to work out if there some problem (say) with the load caused by this light, if it has suddenly developed a fault or anything else as the last thing I want is to buy another expensive light and have a similar problem.

I am grateful for the help and advice

 

[PrenticeBoyofDerry]

So if it holds GU4 lamps a transformer must be connected, is it possible that the transformer was not integral and left behind?
A picture at this time may help!

 

[wigwam12]

The transformer would be integral - nothing was left behind I am almost certain and there is space at the top of the fitting where the transformer is likely to be covered as I said under this foil part - will post up a pic later.

If it is a "surge" on switching on how can I test this and then have it fixed?

 

[wigwam12]

The light - actually 25 x 10w G4 bulbs (5 not working)
View media item 56645
the top - showing the enclosed part with the transformer integral I presume
View media item 56646
The fusebox. It is #2 that keeps tripping
View media item 56647

 

[Spark123]

The inrush current of the torroidal being switched on will probably be the issue.
It may be possible to replace the circuit breaker with one of a different type such as a type C however that is a job for an electrician.

 

[wigwam12]

It is a B6 right now.
I do have BG Home Serve cover with Electrical cover. Likely to be doable via that or do I need to source a Spark?

 

[Spark123]

You'd have to ask them, likelyhood of them actually turning up with the correct MCB is about nil, would probably have to be ordered.

 

[wigwam12]

Fair enough.
For my education, why does it have to be a Type C and not a higher Amp type B?
eBay is awash with B16 and B32 ones for not a lot?

 

[Spark123]

The type (B, C etc) is the magnetic setting which deals with inrush current and fault current.

The setting (6, 10, 16, 20, 32 etc) is the thermal setting which deals with overload current. If you put the wrong setting one in then your wiring may catch fire before the device operates if something goes wrong.

In order to ensure the MCB can disconnect quickly in the event of a fault an earth fault loop impedance test needs to be carried out using a tester, which is a job for an electrician.

 

[wigwam12]

Thanks

 

[Taylortwocities]

Fair enough.
For my education, why does it have to be a Type C and not a higher Amp type B?
eBay is awash with B16 and B32 ones for not a lot?

And C6s, for not a lot.
http://www.ebay.co.uk/itm/EATON-MEM-MCH106-C6-MCB-CIRCUIT-BREAKER-/170923216617

 

[wigwam12]

Brilliant - thanks!