Can anyone help with advice on a peculiar electrical problem? My house is fitted with an earth trip breaker. In the workshop, I have a circuit with four small fluorescent lamps. Of late, when I switch these lamps off, the circuit breaker has been coming out. The lamps work normally and there is no problem when I switch on - only when I switch off.. Any ideas ? Jim Lugsden
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Inductive spike from the choke inducing an earth current - the main rcd sees an imbalance. Your workshop is a long way down the garden, do you export the house earth, or do you have a separate earth spike down there?
Firstly let me say I'm no electrician. I too suffer from the same problem on occasion, but only when the lamp units have become damp in certain climatic conditions - I just live with it.
However, it's my understanding that lighting circuits don't need RCD protection, so can you re-wire around the problem? Failing that if you wire the lights via a couple of switches, so you don't have to power them up all in one hit, then that should help with spikes and surges etc....
At least you know how to trip it ;) I've been getting the power tripping a couple of times a week and having now unhooked most things there is not a lot left other than the armoured cable going down and the earth spike :( It least it is on a separate ELCB to the rest of the house.
I was uunintentionally up at 4.30 this morning after I noticed the power tripped out during the night. Not sure what did it but it's annoying.
However, It has been apparant over the past 12 months or so that the laptop power supplies (and we have 4 laptops in the house) frequently trip either the MCB or RCD or sometimes both when they are switched on.
The point, of course, is that if the 30mA RCDs become such a monumental pain in the arse that the only workable choice is to circumvent them, then anyone with the ability will do so. At which point you might as well have a 100A supply wired directly.
Trying to remove the last 0.000000000000001% of risk at the expense of the first 99.999999999999999% is just bloody stupid. And when the Powers That Be get that message I, for one, will rejoice.
I certainly sympathise with that. The underlying philosophy seems to be everywhere, but particularly in the present practice for earthing everything in sight; my own personal pet hate is central heating radiators - usually plumed in copper to boot. (Oh and bloody kitchen sinks!) When the hell did you last hear of someone being electrocuted by a radiator that had mysteriously suddenly became live FFS!
I agree to some extent but do know someone that got shocks off there central heating system. A section of their central heating become live due to improper earthing and mods. Someone had replaced a section of copper with plastic and hadn't earthed the newly isolated copper section. Due to another problem the isolated section came into contact with live mains and as no earth was present the RCD wasn't tripped. No one was injured in this case and the fault was found and fixed but it does show why some of the requirements exist.
First things first, i'm a Power Electronics Engineer, and I have attended during my career numerous safety training seminars.
During one of these I was told once that a six year old girl had to physically blow a 13 amp fuse in a standard lamp which had not been earthed, and the brasswork had become directly live because her dear old loving grandad had'nt bothered to wire it properly and the live pole insulation had been nicked during re-assembly of the lamp. The thickness of the carpet had provided enough insuation for the potential at the lamp not to be noticed ordinarily.
She was playing hide and seek behind a sofa, and got across from the Lamp to a Radiator. I bet the smell was truly abhorrent. Some of you guys take what I can only describe as a cavalier attitude. I'm honestly surprised some of you are still alive.
These nuisance RCD trips you all speak of so you all derogatorily would have more than likely saved the poor little sods life.
I expect some or all of you will flame me but this is from experience of knowing how dangerous this stuff can be when it's out of control.
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