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Help With Safety of Light Cables and new Ceiling Light

Postby Jonnythebeard » Thu Nov 14, 2019 8:47 pm

I'm looking at changing the ceiling light to another metal one.
However I'm concerned with the old cabling, is this safe?

I've also looked at changing the light switches, but they don't seem to have an earth. Am I right in saying a metal one is out of the question, but also that a plastic one is fine with no earth?
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Postby ericmark » Sat Nov 16, 2019 12:23 pm

It looks like plastic cables, so they should be OK, the rules changed in 1966, before 1966 you did not need an earth to lights, but after that date you do, even if the earth is not used. But there is no need to change existing wiring, but all items need to be class II if there is no earth.

Class II or double insulated items will have the double square sign to show class II, however label can fall off, and it means plastic switches with either plastic screws or blanking bits that hide the screws specially if using a metal back box, I failed to find a fluorescent lamp which was class II, did find a 2D lamp.

Class II can have bits of metal, but I have failed to find a bulb which is classed as class II, no one worried about tungsten bulbs, you could not touch them anyway, and E14, E27, and G9 bulbs don't have any part which could be earthed even if you wanted, BA22d bulb however could need an earth although unlikely as really same as E27 just with different cap, but fluorescent fittings often had tubes with an earth strip running length of tube so to say bulbs and tubes don't need an earth is wrong. However in the main if centre of Edison screw in line and screw is neutral then you are OK if the fitting has the double square mark.

Problem is where the lamp is in two parts, like a ceiling rose and lamp holder both need to be class II, and often not marked, so safe way is use plastic fittings.

One should test the earth, however that can produce a danger, so although an electrician will test it, I am not keen to tell DIY people to test it as there is a danger with the testing and the meters are expensive.

Although MK do make a bulb holder where terminals are dead until bulb is fitted, in the main you can stick your finger in a lamp holder as get a lethal shock, lights are the odd one out, any other electric item any live parts need a key or a tool to access them, but you can unscrew a ceiling rose or stick your fingers in a lamp holder so you should always switch off before changing a bulb, and your unlikely to touch the lamp at any other time.

The switch however you must need a tool or key to access live parts.
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Postby Mr White » Sat Nov 16, 2019 6:08 pm

You are correct in regard to the light switches.

As your cables have no earth, although they were up to standard at the time, I would suggest you have an EICR carried out to check the quality of your installation.
Just because the cable have no earth is NOT a fail, you can as you said have all plastic fittings, but cables have been known to start to breakdown when they are 40 years old.
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