Strange Lighting Fault

[tomberry]

I have recently moved into a house and have noticed something rather strange.

The light in the understairs cupboard has it's own switch, but the switch will not work unless the living room lights are off. Fair enough as a couple of the lights in the house have strange switching arrangements.

However, when the cupboard light is switched on, the bulbs in the living room light fitting glow slightly, and I cant think what could be the cause.

I have someone coming to replace the rewirable fuse board with a consumer unit soon, so would like to know it this is likely to need fixing before then.

Any ideas?

 

[wingcoax]

Somewhere in the circuit the lights are wired in series. Your electrician will soon sort that out.

 

[ericmark]

I will guess the light in the understairs cupboard takes it's supply from the living room lights switch not from the ceiling rose and there will be no neutral at the switch so it is using the switched line as a neutral.

To correct would require a neutral and likely to do that will mean new cables so it may not be so easy to sort.

 

[Iggifer]

but if the fuseboard is under the stairs, easy enough to take a new cable to the switch, loop at the switch and up to the light

 

[Lectrician]

I will guess the light in the understairs cupboard takes it's supply from the living room lights switch not from the ceiling rose and there will be no neutral at the switch so it is using the switched line as a neutral.

To correct would require a neutral and likely to do that will mean new cables so it may not be so easy to sort.

My guess too - Saw a socket spurred from a switch in a barn once. They wondered why their kettle took so long to boil, and didn't notice the row of high bays trying to fire...

 

[ericmark]

but if the fuseboard is under the stairs, easy enough to take a new cable to the switch, loop at the switch and up to the light

Yes clearly can take the whole supply from elsewhere but if that was easy then why take it from switch in first place?

It is jobs like this that cause the borrowed neutral situation which is extremely dangerous so a little loathed to suggest ways around the problem until we get a reply and can judge if likely to be a problem.

 

[ban-all-sheds]

Saw a socket spurred from a switch in a barn once. They wondered why their kettle took so long to boil, and didn't notice the row of high bays trying to fire...

Heaven forbid, though, that anybody should dare to suggest that competence be a prerequisite for doing electrical work.


OOI, did they also wonder why their kettle didn't work at all when it was dark?

 

[Iggifer]

Yes clearly can take the whole supply from elsewhere but if that was easy then why take it from switch in first place?

Perhaps done by a DIYer who was not comfortable going into the fuseboard/thought what he was doing was correct

 

[tomberryuk]

Thanks for the thoughts everyone!

The fuseboard is currently in the garage, but I am having it moved into the utility room which is actually right next to the understairs cupboard.

But I'm going to be decorating the hallway soon-ish anyway, so I reckon the best way is to run a new cable to the ceiling rose in the hallway and have the light fed normally from the lighting circuit, rather than having that light on its own circuit. I dont mind patching the plaster myself after any chasing out!

The electrician is coming tomorrow, so I'll ask him about it then!

Thanks again everyone

 

[tomberryuk]

Also didnt realise that I have 2 accounts! One auto logs in at work, and this one auto logs in from home

 

[Iggifer]

You don't need to have it on it's own circuit if it's fed directly from the consumer unit - you can have two cables coming out of the downstairs lighting mcb, nothing wrong with that per se

 

[securespark]

It'd be a good idea to have a light on a separate circuit (or an emergency light) above the CU, so that if your lighting goes out, you've got something to see by.

 

[Iggifer]

Yup I've got an 8w EM fitting wired into my downstairs lighting circuit, separate to the under stairs light fitting so if it trips, the light is there, handy for working in the CU too