Any Electricians in CC land

[Night Train]

I have checked light fittings for loose wires, but will have another look tomorrow in the daylight.

On the consumer board the downstairs lights are on the same fuse, so if it was a loose connection in there all the downstairs lights would be off?

Not always.

Depending on the quality of the electrical work a badly stripped cable could have a notch cut around it where the insulation was stripped off the conductor. When two circuits are connected to a single MCB terminal, as is sometimes done, one can snap off leaving the other cable still securely connected. A break like this could be in the phase or the neutral conductor so worth checking both.

However, if the circuit is a single radial and some lights are working and some not then it is most likely a loose or broken connection in either the phase or neutral conductor in a ceiling rose. This should be easy to spot.

But, if you have halogen down lighters or similar then the connections could be hidden in the ceiling void, either in a junction box or a ceiling rose pretending to be a junction box. This could be loose and accessible from one of the holes in the ceiling when a down lighter is removed or it could be secured to a joist and not accessible without lifting floorboards above.

It all really depends on the installation and how it has been done and if any corners have been cut.

In extreme cases I have found cables that were damaged during installation, passed an instrument test during handover, and then failed sometime later due to movement, vibration or localised heating.

 

[snorri]

Although nothing has tripped on the consumer board, could there be a faulty trip switch?. Try swapping the switch around with a known good one. These are usually 'plug in' type things.

 

[addictfreak]

Not always.

Depending on the quality of the electrical work a badly stripped cable could have a notch cut around it where the insulation was stripped off the conductor. When two circuits are connected to a single MCB terminal, as is sometimes done, one can snap off leaving the other cable still securely connected. A break like this could be in the phase or the neutral conductor so worth checking both.

However, if the circuit is a single radial and some lights are working and some not then it is most likely a loose or broken connection in either the phase or neutral conductor in a ceiling rose. This should be easy to spot.

But, if you have halogen down lighters or similar then the connections could be hidden in the ceiling void, either in a junction box or a ceiling rose pretending to be a junction box. This could be loose and accessible from one of the holes in the ceiling when a down lighter is removed or it could be secured to a joist and not accessible without lifting floorboards above.

It all really depends on the installation and how it has been done and if any corners have been cut.

In extreme cases I have found cables that were damaged during installation, passed an instrument test during handover, and then failed sometime later due to movement, vibration or localised heating.

Cheers, a very comprehensive answer. Fingers crossed that its easily located tomorrow.

 

[Night Train]

Cheers, a very comprehensive answer. Fingers crossed that its easily located tomorrow.

Also, when checking connections are tight don't just test the screw is tight with a screw driver. Pull the cables to see if they are actually held by the tight screw.

Sometimes overzealous tightening can crush a conductor to the point of fracture and so the cable isn't held anymore. Also if there are more then one conductor in the same terminal hole the screw can tighten on one and miss the other. The other common error is that with insulated terminals, especially in ceiling roses, the brass terminal is so deep in the insulation that a conductor doesn't even reach the screw.


Finally, Don't do it with the power live! That is my job!

 

[addictfreak]

Also, when checking connections are tight don't just test the screw is tight with a screw driver. Pull the cables to see if they are actually held by the tight screw.

Sometimes overzealous tightening can crush a conductor to the point of fracture and so the cable isn't held anymore. Also if there are more then one conductor in the same terminal hole the screw can tighten on one and miss the other. The other common error is that with insulated terminals, especially in ceiling roses, the brass terminal is so deep in the insulation that a conductor doesn't even reach the screw.


Finally, Don't do it with the power live! That is my job!

Thanks again, although my knowledge of electrical work is limited I can assure you the power always goes off!

 

[slowmotion]

NT has way more experience than I do, but here's another rather grim suggestion. It could be that a cable run on the lighting circuit has been joined using a junction box within the floor/ceiling cavity. If there is a JB with a dodgy connection, it wont be easy to locate. To find it (without ripping up a lot of flooring), someone is going to have to use a professional cable tracing gizmo. That almost certainly means calling in a sparks.

 

[Night Train]

NT has way more experience than I do, but here's another rather grim suggestion. It could be that a cable run on the lighting circuit has been joined using a junction box within the floor/ceiling cavity. If there is a JB with a dodgy connection, it wont be easy to locate. To find it (without ripping up a lot of flooring), someone is going to have to use a professional cable tracing gizmo. That almost certainly means calling in a sparks.

Already mentioned in post 16.

Don't always need cable tracing gizmos, I never used one in decades of electrical trouble shooting work. A good eye and experience of how a job should be done, how it is often done, how it is sometimes done and how it can be done badly and that is enough of a clue for finding where the fault is likely to be.

I have found missing sockets that no one knew had been buried in plaster for 10 years, junction boxes hidden under floors and in walls, found cables damaged by builders years previously and then hidden and crossed connections between flats in house conversions.
I also did a lot of inspections for insurance fraud where 'an electrical fault' was suggested by the claimant. It is amazing how much electrical 'forensic' evidence can be found when one knows where to look and what to look for.

 

[slowmotion]

Sorry NT. I was fiddling with my catapult at the back of the class. Yes, it's the forensic stuff that marks out the pros from the wannabes, and I am certainly the latter.

 

[subaqua]

Already mentioned in post 16.

Don't always need cable tracing gizmos, I never used one in decades of electrical trouble shooting work. A good eye and experience of how a job should be done, how it is often done, how it is sometimes done and how it can be done badly and that is enough of a clue for finding where the fault is likely to be.

I have found missing sockets that no one knew had been buried in plaster for 10 years, junction boxes hidden under floors and in walls, found cables damaged by builders years previously and then hidden and crossed connections between flats in house conversions.
I also did a lot of inspections for insurance fraud where 'an electrical fault' was suggested by the claimant. It is amazing how much electrical 'forensic' evidence can be found when one knows where to look and what to look for.

kitchen fitter specialist install with a 2 week part p then

only time i have ever used a cable tracer is on multicore control cables over a mile long in car plants etc. domestic fault finds can be interesting , and i learnt my craft as an apprentice fault finding on new builds when sparks on price couldn't be bothered to find their own mistakes.

 

[Spinney]

Are electrical faults covered under the 10-year guarantee you get on new houses? Might be worth checking the conditions on that before you call in an electrician.

 

[asterix]

A slight aside, but I discovered that houses have their own fuse where the power comes in. All our power went even though no blown fuses (its an old house) and it turned out to be a large single fuse, like those in plugs but much bigger, that had failed.

 

[subaqua]

A slight aside, but I discovered that houses have their own fuse where the power comes in. All our power went even though no blown fuses (its an old house) and it turned out to be a large single fuse, like those in plugs but much bigger, that had failed.

The service cut out fuse blewm wow, only ever popped one , saturday 11.30 am miles from a wholesaler. The reason release tabs on mcb's are now plastic

 

[Archie_tect]

A slight aside, but I discovered that houses have their own fuse where the power comes in. All our power went even though no blown fuses (its an old house) and it turned out to be a large single fuse, like those in plugs but much bigger, that had failed.

NHBC and equivalent 10 year 'guarantee' cover all faults for 2 years then revert to structural only for next 8... but would be worth mentioning to housebuilder; if several houses have had similar problems and they could get the original electrical firm to fix it as a latent defect [up to 6 years].

 

[addictfreak]

Ok all sorted, Traced to a loose connection in one of the other lights (downstairs loo) on the loop. The problem will have been down to me from when I changed all the light fitting shortly after moving in.

Thanks for the input guys.

 

[subaqua]

Ok all sorted, Traced to a loose connection in one of the other lights (downstairs loo) on the loop. The problem will have been down to me from when I changed all the light fitting shortly after moving in.

Thanks for the input guys.

at least it wasn't a sunday afternoon call out favourite. mr DIYer changes a light and puts all reds/browns together and all blacks/blues together switches on and bang.
£150 nearly every sunday for 3 years when on call out duty .