Earthing the base of a metal standard lamp

Msitekkie · Apr 11, 2023

westward10 said:
Can you show a picture of where the earth is connected. Yes the lock ring holds it all together.

I presume you mean the earthing on the lamp holder in the 2nd photo. As the one on the base is pretty clear. So I have attached another photo showing the V shaped plate removed, where I believe the earth wire would go.

The discussion has got a bit side-tracked on fixing/replacing the lamp holder & it turns out this does screw on - (it was firm but not screwed on when I removed it), so apologies for not being clear on that point.

So the discussion really comes back to where we started - do I need to earth to the point on the base & if so what is the correct (original?) method. Or do we rely on earthing continuity from the lamp-holder.

[ElectriciansForums.net] Earthing the base of a metal standard lamp

DPG · Apr 11, 2023

I think personally I would add an extra earth wire to join the nut/bolt on the base up to the lamp holder. Is there enough room to thread one through the upright pole?

Msitekkie · Apr 11, 2023

DPG said:
I think personally I would add an extra earth wire to join the nut/bolt on the base up to the lamp holder. Is there enough room to thread one through the upright pole?

No. That's what led to my original posting & the question mark over how it was attached originally.

DPG · Apr 11, 2023

Msitekkie said:
No. That's what led to my original posting & the question mark over how it was attached originally.

Sorry, just realised it's 3 core up the stem already. I'll re-read the thread.

Msitekkie · Apr 11, 2023

DPG said:
I think personally I would add an extra earth wire to join the nut/bolt on the base up to the lamp holder. Is there enough room to thread one through the upright pole?

Actually revisiting that issue has set me thinking about using singles, although the cable still needs to be double insulated to the plug. So I wonder if I remove some of the outer insulation where the pole narrows higher up, effectively giving me singles where needed... I have some sleeved 1.5mm earth single (flex) that I might just squeeze through if I remove the insulation from the top section of that. I think it will still be tight though.

westward10 · Apr 11, 2023

Msitekkie said:
I presume you mean the earthing on the lamp holder in the 2nd photo. As the one on the base is pretty clear. So I have attached another photo showing the V shaped plate removed, where I believe the earth wire would go.

The discussion has got a bit side-tracked on fixing/replacing the lamp holder & it turns out this does screw on - (it was firm but not screwed on when I removed it), so apologies for not being clear on that point.

So the discussion really comes back to where we started - do I need to earth to the point on the base & if so what is the correct (original?) method. Or do we rely on earthing continuity from the lamp-holder.

I cannot see an earth terminal. I assume there is no locking ring, you really need a new lamp holder.

davesparks · Apr 11, 2023

As you have an insulated and sheathed cable running up to the lampholder then the earth only really needs to be connected at the lampholder.

Replace the lampholder with a new, complete, one and connect the earth.

brianmoooore · Apr 12, 2023

A modern switched brass lampholder will be almost identical in appearance to your existing one, costs very little, and will have an earth terminal attached to the base part. All that is needed is to replace the current lampholder and connect the earth wire in the flex to it, making sure that there is still slack in the earth wire if the live and neutral were pulled tight.
Keep the outer sheath on the flex all the way up into the lampholder.

Msitekkie · Apr 12, 2023

westward10 said:
I cannot see an earth terminal. I assume there is no locking ring, you really need a new lamp holder.

Thanks for your continued feedback.
So I cannot see any other purpose for the V shaped plate to be screwed here, other than to hold the earth. The original piece of earth at the bottom is bare wire, so I am guessing it was laid along & held in place by the narrow part of the V when screwed down. Quite different to what we are used to these days. It's possible I am wrong though & the earth was just connected at the base.

With a new lamp holder I'm thinking I have the risk of the thread being different as it's an antique item? (Belonged to the customer's Grandmother).

Msitekkie · Apr 12, 2023

One approach I am considering, is adding an extra earth wire from the plug to the base & encasing this with the original flex in some braided sleeving.

brianmoooore · Apr 12, 2023

The thread in the base is likely to be close enough. Two standard sizes - 3/8" and 1/2".

mainline · Apr 12, 2023

There is only one way of doing it properly, as I said in #6

You will also have to ensure that the cable is secured in the lamp so can't easily be pulled out.

davesparks · Apr 12, 2023

Msitekkie said:
One approach I am considering, is adding an extra earth wire from the plug to the base & encasing this with the original flex in some braided sleeving.

But the base doesn't need earthing, the lampholder does!

davesparks · Apr 12, 2023

Msitekkie said:
With a new lamp holder I'm thinking I have the risk of the thread being different as it's an antique item?

Yes it will be almost certainly be different, you will need to use the appropriate imperial to metric adaptor.

brianmoooore · Apr 12, 2023

davesparks said:
Yes it will be almost certainly be different, you will need to use the appropriate imperial to metric adaptor.

Rewired and replaced the lamp holders on several multi lamp old chandeliers over the years, and as far as I can recall, I've never had to use an adaptor, other than 3/8" to 1/2" occasionally.

Earthing the base of a metal standard lamp

Msitekkie

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DPG

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Msitekkie

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DPG

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Msitekkie

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westward10

davesparks

brianmoooore

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Msitekkie

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Msitekkie

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brianmoooore

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mainline

davesparks

davesparks

brianmoooore

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