DIY Doctor

earthing downlights

Postby brickiepaul » Fri Dec 07, 2007 12:16 am

does the body of a metal downlight have to be earthed, have fitted g10 downlights which although have a provision for the earth in the connector block do not have any way to then earth the body itself, can modify to earth them but do they need to ?? have been told to drill them to connect earth, also 12v downlights have no provision for earth what would be the norm on these ? into a jb before the transformer i presume?

advice apprecieated as always
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Simply Build It

Postby BLAKEY1963 » Fri Dec 07, 2007 1:20 am

ANY electrical item that is metalframed is a class 1 appliance. under fault conditions this can conduct a fault current and become a shock hazard.
this is why it is vital that this metalwork is earthed , to disconnect the protective device under fault conditions and prevent the operater
from recieving an electric shock.
ensure that your fittings are earthed.
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Postby gjbiker68 » Fri Dec 07, 2007 11:51 pm

This is of interest to me also. I just bought mains downlighters that only have live and neutral with no earth facility. The fitting instructions also state that no earth is required but they have a metal body. Why is this ? :?
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Postby kbrownie » Sat Dec 08, 2007 8:19 am

Hi gjbiker68,
This is because they are considered to be double insulated, something that I have questioned on the docs website before.

This means if 'Electrical power tools or equiptment, such as light fittings, with parts that carry current being insulated from the person using it by internal insulation in addition to a non-conducting outer casing.'

Put simply, the light fitting has an extra level of insulation through its cable, to protect the consumer from the parts of the light fitting that carry an electrical current.

Most Downlight fittings have a plastic casing that the cables are installed in and the bulb contact points are incased in a insulated pot. So almost eliminating an earth fault to occur.
But I beleive Blakey has a point and total respect to him (much wiser than I) That's why I questioned this sometime ago.

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Postby 333rocky333 » Sat Dec 08, 2007 7:18 pm

Not sure but is it due to the gu 10 lampholders being classed as double insulated possibly :?:
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Postby gjbiker68 » Sun Dec 09, 2007 1:47 am

Thanks guys, I think I'll see if I can attach an earth somewhere anyhow. Better safe than sorry eh ?

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