Earthing table lamps

Frithgar · Jan 26, 2012

Hi,
I've just started making wooden table lamps, made entirely from wood with a GP 091 B 22 Brass pushbar (switch) lampholder attached to the top. The lamp holder is attached to the lamp via a small brass plate that it screws directly onto, the plate is attached to the wooden lamp via three small brass screws. My question is, do I need to earth the brass lamp holder and/or have an earth in the cable? At present I am using 0.75 two core round flex attached to a 3amp fused plug. The lampholder is marked with CE T2/250. I'm asking because someone close to me has said he thinks the cable needs to have an earth core, even if it's not attached to the lamp. I'm unsure where to find the precise regulations concerning this and if no one is able to answer my question can you please point me in the right direction?
Thankyou for your time
Frithgar

Silly Sausage · Jan 26, 2012

It definitely needs earthing.
It should have a screw terminal on the lamp holder to connect the earth to.

Richard Burns · Jan 26, 2012

Welcome to the forum.

Agree with Archy the metal of the brass lamp holder must be earthed, most of them have a screw terminal block either attached to the base or just at the bottom of the holder.

If you have 3 amp fusing on the plug then the cable csa could be reduced to 0.5mm2 3core flex if you have problems with the dimensions.

If the holders you use do not have earthing terminals then you need to get ones that do.

HandySparks · Jan 26, 2012

All above is good advice. And make sure that you have a proper method of securing the flex. The connections in the lampholder must be isolated from any pulling or twisting of the flex. There are specified values for both pull and twist in the relevant standards, but it's been a long time since I looked.

jumpin jax · Jan 27, 2012

perhaps the op needs to know why it needs earthing and will understand in the future?

Frithgar · Jan 27, 2012

Thankyou for the responses, I have one more question related to this now. Whilst the brass lampholder in question does indeed have a small earthing block at the base, is it acceptable to pinch the earth underneath the base plate with one of the fixing screws? This would look better than have a wire trailing out from underneath up to the earthing block. I know the wire would only be about 15 mm long, but from a customers point of view, I wouldn't want any wires on show. Or perhaps there is a differant type of brass lamp holder that someone may be able to suggest that has an earthing block hidden from view?

jumpin jax · Jan 27, 2012

the lampholder in question probably feeds the earth lead from the inside out not on the outside of the lamp!
the lamp holder needs the earth in case the live conductor comes astray and touches the metal case making the holder live for someone to touch.

Frithgar · Jan 27, 2012

The earth is not connected on the inside of the lampholder, the internal part is completly plastic lined apart from the two connectors for the the line and neutral feeds. The only earth block on the brass part of the lampholder is on the outside at the base, I'm not sure how to upload a pic to this page, but if you google GP 091 B 22 you'll find a picture of them in the first few links. If I was to swap a plastic lampholder for the brass one I'm using would I still then need to earth the lamp? I've bought several lamps over the years and none have ever been earthed.

nickblake · Jan 27, 2012

If you use a plastic lamp holder then no , what you should lood at is any metalic parts of the light, and class them extraniouse , parts that could become live in the event of a fault ,so changing the lampholder removes the metalic part so should be ok , get a local spark to put a PAT test on it them you'll know they are safe

Richard Burns · Jan 27, 2012

Frithgar said:
Thankyou for the responses, I have one more question related to this now. Whilst the brass lampholder in question does indeed have a small earthing block at the base, is it acceptable to pinch the earth underneath the base plate with one of the fixing screws? This would look better than have a wire trailing out from underneath up to the earthing block. I know the wire would only be about 15 mm long, but from a customers point of view, I wouldn't want any wires on show. Or perhaps there is a differant type of brass lamp holder that someone may be able to suggest that has an earthing block hidden from view?

You should find (or may be able to adjust) that the earthing block has a hole through the brass so with care you maybe able to push the earth cable through from the inside with a small pair of pliers and then the green and yellow would not be visible.
Not a good idea to just clamp the cable in the fitting, but would probably work.
All Plastic lamp fittings would not need an earth.