Wierd Electrics

[John]

I went round to a friend of my mums today to swap two light fittings. They were both standard type modern metal fittings. His fuse box is one of the old type rewireable ones with 4 carriers in it, two Red spotted, one white spotted and one with masking tape over it so not sure of its colour. Now for safety sake I always turn the light on and then pull the fuse to make sure it is dead. I flicked the switch and the light didn't come on. He said "Oh it's because the dining room light is on"!! Apparantly it has been like that since they bought the house in 1987, if you switch the dining room light on the living room. kitchen, hall and landing go off!! He said they are now used to it and it isn't a 'problem' anymore. He said he had the electricity board around when they first moved in and they said it was safe but not conventional!

Now the really wierd bit, when pulling the fuses I tried the one with masking tape first, nothing, then the white one, nothing, then one red one, nothing, final red one light went out along with theTV,video,fridge,kettle,cooker, etc. Everything in the house downstairs and all their lights seemed to go through this one red 30 Amp fuse apart from the immersion heater which was was on the white one. The upstairs sockets were fed by the other red fuse.

Needless to say I didn't change the fittings and advised him to get a sparky in, I know my limits!!

Cheers

John

[Palindrome]

Who knows? The actions of the DIY electrician passeth all understanding. Maybe the fuse wire in the "masking tape" carrier (that fed the lighting) went too often, so someone moved the wire from that fuse to join the ones at the red one. Similarly, maybe they removed a landing two way switch for re-decorating and wired it up wrong when putting it back - so the looped-on lighting circuit is now being interrupted.

I'd say leaving it as it was until a tame electrician sorted it out was the best policy, too. It probably doesn't need that much doing, other than running a dedicated service to the cooker and new consumer unit to provide the extra way.

-- Sue

[Owain]

Sounds like the L is looped at the switch, and someone's looped the living room (and downstream) lights off one of the L terminals of a

2-way switch, and the dining room light is on the other L. In other words there should be 2 reds going to COMmon and the dining room light to L.

Owain

[Ron O'Brien]

Reminds me of the time in the late 60's/early 70's, when my dad - who lived in a rented cottage - used to moan about his electric bill and had the electric board out a few times to test his meter and use. This went on for a few years until the landlord decided to up-grade all his houses and extend the kitchens. Whilst working on the house nextdoor the electrician apparently flew across the room! whilst taking out the cooker point. It transpired that nextdoors cooker point was wired into my dads via a spur off his cooker point! - very Heath Robinson! Needless to say dads electric bills were about 30% cheaper thereafter, not sure the old lady next door was quite so happy though!

Ron

[<me9]

I had aproblem with a friend's lights. I was actually working on adding a spur for a garage door, which I /still/ haven't done, due to the time wasted on sussing out what was going on.

The easiest to solve was the lights appearing to be mainly on one fuse, but seemed different at other times. It turned out a wire was swapped in a 2G 2W switch for the hal/landing lights, causing the up and down circuits to be randomly cross connected. This came about by him replacing the switch with out knowing what he was doing.

It was also replaced by a metal faced switch, for which no earth was available. I'm trying to persuade him to replace them with insulated ones.

Is it possibe to get double insulated metal finished light switches so that they don't need an earth?

[Doctor D]

I've never seen metal switches that don't need earthing. The lack of an earth at a light switch usually means the wiring dates from the sixties and probably needs replacing.

I was also taught (I hold C&G under the 15th edition) not to connect separate circuits to the same face plate. I would have wired the landing light to the downstairs circuit, or had the two way landing switch (upstairs circuit) in a different location to the hall (downstairs circuit) and not sharing a face plate or back box.

In the sixties it was not uncommon to "borrow" an neutral from the upstairs lighting circuit for the landing light despite it being powered from the downstairs circuit.

[Dave Plowman (News)]

You wouldn't like my place, then, where you can switch on or off all the landing lights from the front door - three floors on three circuits. And the idea of using separate switches is a no-no aesthetically. Nor would I have all the landings on the same circuit either for safety reasons.

It was as big a bodge then has now. Luckily RCDs prevent such bad workmanship.

[PeterC]

An old GF needed a mid-flight light (she's disabled and has to have good lighting) so, while I was doing the job I wired all 3 to 1 2-way circuit and at the same time rewired so that the whole lot came from 1 circuit. I don't like the system where the 2 circuits are linked by the stairway lights.

Trouble is, all the plates are metal and the [separate, 2-way] board for lighting doesn't even have an earth to it - I suggested that she put another coat of laquer on :-)

[Dave Liquorice]

*Might* prevent such bad workmanship. If the borrowed N still returns through the RCD that the Lives comes from there will be no imbalance to trip the RCD.

[Doctor D]

It seemed more common then. Possibly due to the lack of three core and earth cable?

RCDs don't detect this unless one circuit is connected without the RCD, or RCBOs are used.

[Dave Plowman (News)]

You'd not normally run triple and earth to the fitting, though. Just between switches.

Indeed. Although I've seen neutrals borrowed from any circuit including rings - so might make a difference on split load types.