I changed some wall lights at the weekend. After wiring in, realised that the light casing was live. On testing found live-neutral was 240v, but earth-neutral was also 120v. When testing connections above the ceiling found the same, even with the earth cable disconnected. I presume there is a problem with the neutral, but don't know where to start. Please help !
Live light fittings !
- Thread starter JIMBO1
- Start date
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It seems pretty obvious that the problem is with the earth. To be more precise, you haven't got one! If the light is working you have a good live connection and, probably, a good neutral connection. I say probably because your neutral could be wired to eath and the light would still work. If you leave the earth wire floating, most meters will show it to be midway between live and neutral. That's due to capacitive coupling along the cables.
Of course it makes no difference whether the earth is connected to the light or not. It's other end goes nowhere. Since you have the same problem in the ceiling lights you are looking for a break well back down the line. Try the consumer unit first.
Of course it makes no difference whether the earth is connected to the light or not. It's other end goes nowhere. Since you have the same problem in the ceiling lights you are looking for a break well back down the line. Try the consumer unit first.
Thankyou - excuse my ignorance, but even if the earth cable is not a good earth, the light fitting should not still be live (unless the fitting is faulty). The 'live' earth runs through the switches as well. I will check the earth at the consumer board later.
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When you say that the light casings are live, is that because your neon driver lights up? This doesn't have to mean that the lights are faulty. You have a long run of cable in which live and earth wires run side by side. This capacitance will pass enough current to make a neon light up, though not as brightly as it does on the live wire. Most meters will also show a reading. For a real test you need to draw some current. Try connecting a light bulb from that 'earth' wire to a real earth. If it lights up, the fitting is faulty - but it won't.
Your main problem is that if any of your fittings or switches anywhere on that circuit fail with a live to earth short, the whole lot really will be live and you'll find out the hard way! I strongly recommend you get it sorted yesterday.
Your main problem is that if any of your fittings or switches anywhere on that circuit fail with a live to earth short, the whole lot really will be live and you'll find out the hard way! I strongly recommend you get it sorted yesterday.
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