US Lamp

[gerryb]

I have a couple of table lamps from the US and im going to rewire them for the usual reasons including adding an earth.

The switch is brass or brass coated and theres a cardboard insert around the bulb which is, i suppose some insulation, but there is no double square mark so perhaps they predate that particular bit of safety labelling.

But i have a couple of questions

1/. why do North American lamps not have an earth? is the lower voltage less dangerous - seems unlikely - and having lived there for a bit their Breakers and RCD's dont seem to suggest theres no need for an earth. So why do we have an earth and they dont? Just historical?

and

2/. where on this lamp would add the earth tag?

thanks all in advance

 

[Sureitsoff?]

Looks like it would be easier to fit a new brass lamp holder with a built in earth terminal.

 

[gerryb]

a good suggestion but im keen to keep as much of the original for sentimental reasons and quite like the rotating switch which is integral to the current holder and also concerned about the metric/ imperial dimensinos of the thread, and so on. Is there a sensible place to attach the tag or you think replacement absolutely necessary? cheers

 

[Ragnar_AT]

Is there some kind of enclosed space for connections in the base of the light?

 

[gerryb]

yes, the cable runs up through the threading core and there is space to add a connection

 

[securespark]

Keep the old switch mechanism for looks, but make it redundant by adding a switch in the flex.

 

[Taylortwocities]

why do North American lamps not have an earth?

Maybe their voltage doesn't kill people, or there's more risk from gun-toting people...

 

[ericmark]

I look at the electronic chip, and think no way connecting that to 230 volt, so would look at new lamp holder

this one you can see the earth connection.

 

[Taylortwocities]

Breakers and RCD's dont seem to suggest theres no need for an earth

GFCI is what Americans call RCDs.
How do you think they work if "theres no need for an earth" ?

 

[gerryb]

i know how they work, but dont understand why these lamps dont have an earth, hence the question. not sure if you are suggesting an answer in your response, but i would love to know what it is.

 

[ericmark]

In the UK, I have seen lamps marked

and still made of metal, but on inspection one normally finds polythene sleeve inside all the tubes, so the wiring is nowhere near the metal. And the lamp holder its self is made of plastic.

Doing inspection and testing of in-service electrical equipment, often called PAT testing, I have many times found items which have not got the mark, so no option but to fail it. It may be safe, but I can't take the risk, also found item marked which are clearly not, mag mount drill, where the drill is class II, but the mag mount is not, same with lamps, where the bulb holder may be class II, but the lamp is not.

If it was mine, I would fit a 24 volt bulb, and use a 24 volt isolation transformer, however USA screw bulbs are 28 mm, and Europe are 27 mm, so you would need to get a bulb from the USA. Or change the bulb holder, and clearly the electronics would have to go.

 

[Robin0577]

I look at the electronic chip, and think no way connecting that to 230 volt,

The triac is a BT136-600 rated at 4A 600V, so that should be perfectly OK. The capacitor is X2 rated, so also OK. I'd be much more worried about the cardboard insulation and I'd also be tempted to replace the lampholder, except for the fact I've never seen a UK/EU lampholder with a built in dimmer like that...

If you really want to preserve the originality, you could just run the thing from a 110V isolation transformer. (NOT an autotransfomer)

P.S. That's almost certainly going to be an old school leading edge dimmer and won't work with LED bulbs, even so called dimmable ones.

 

[ericmark]

I would think if the triac is connected to a touch control, earthing the metal would stop that working, but to use on double the design voltage can't be good.

 

[ebee]

I look at the electronic chip, and think no way connecting that to 230 volt, so would look at new lamp holder View attachment 346469this one you can see the earth connection.

It also means that you could have a BC (Better Connection) lampholder rather than those ES (Extremely Silly) lampholders too, I would hope that a 240/230V rated lamp is inserted and not a 120V one

 

[FrodoOne]

You need to determine the thread size on the existing lamp and obtain an appropriate 230 V rated switched Lamp Holder.
(Perhaps, one of these - https://www.amazon.co.uk/s?k=switch...aps,374&ref=nb_sb_ss_pltr-data-refreshed_1_26 )

If necessary, it is usually possible to replace the "threaded tubing" with a (not larger diameter) new one, to suit any "present day" lamp holders.
(e. g. https://lightingspares.co.uk/collections/threaded-rods )

However, I really do not see a way in which you could get any Earth wire to any external terminal on those fittings - and it would not look well, even if you did !

I can't be sure if the base is metal or wood.
In any case, it should be possible to
install a "Ring Terminal Wire Connector" around the threaded tube at the base
and
connect the Earth there,
running just the insulated Line and Neutral wires up the tube to the Lamp Holder.
("Ring Terminal Wire Connectors" are available with "holes" of up to 10m
There are also these https://www.lampspares.co.uk/1-2-threaded-rods/ )

1/. why do North American lamps not have an earth?

While they do now, they didn't (in the old days)
and
that is an old lamp - even although it has been "added to".