Rewiring an English Lamp for American Use

[Amethyst]

Alas, I am afraid this may be the case. I was wondering why I couldn't seem to remove the socket.

Only potential problem when you try to rewire is if the original manufacturer soldered the bulb socket to the lamp head.

 

[atmsmshr]

If your iPhone can snap a pic of the socket base, we can tell you how to remove it without too much fuss. Thought I saw beads of solder in the first post - but an angled close up will tell the tale.

 

[pb4uski]

Alas, I am afraid this may be the case. I was wondering why I couldn't seem to remove the socket.

Will a US light bulb screw into the base? If so, then why monkey with it? Screw in a US bulb, get a UK to US adapter and put it on the plug end and plug it in and declare victory.

 

[euro]

Will a US light bulb screw into the base? If so, then why monkey with it? Screw in a US bulb, get a UK to US adapter and put it on the plug end and plug it in and declare victory.

This!!!!!

 

[OldShooter]

Ack! Too hard. Too hard. I should have unsubscribed; you guys are making me nuts.

@Amythyst, either do as @pb4uski suggests or send the thing to me.

I will inspect for the highly unlikely case that there are problems. I will then cut the English plug off, strip and twist the wires, and poke them into a 110VAC socket. In the highly likely case that the lamp works just fine, I will go to HD, buy a plug, and install it pro bono. I will then return it to you.

For background, I have an MSEE. I have installed literally miles of 110vac house wiring and 220vac wiring for welders, compressors, & backup generators. I have also worked on broadcast transmitters where the final amplifier voltage was in the kilovolts-- seriously dangerous stuff. I am not yet a crispy critter and I do not expect that to change from messing with this trivial project.

 

[Amethyst]

Oh, my! I am not worthy

.

@Amythyst, either do as @pb4uski suggests or send the thing to me.

I will inspect for the highly unlikely case that there are problems. I will then cut the English plug off, strip and twist the wires, and poke them into a 110VAC socket. In the highly likely case that the lamp works just fine, I will go to HD, buy a plug, and install it pro bono. I will then return it to you.

For background, I have an MSEE. I have installed literally miles of 110vac house wiring and 220vac wiring for welders, compressors, & backup generators. I have also worked on broadcast transmitters where the final amplifier voltage was in the kilovolts-- seriously dangerous stuff. I am not yet a crispy critter and I do not expect that to change from messing with this trivial project.

 

[OldShooter]

Oh, my! I am not worthy

OK. PMs exchanged. I'll report back.

Regarding US lamp fittings, most seem to be based on the standard 1/8" NPT pipe thread. This is a tapered thread, as are all NPT threads, but I often see fittings that are straight. If any of you guys are messing with lamp fittings and need to buy something, though, the 1/8" NPT fitting drawer at your friendly neighborhood hardware store is a good place to start.

 

[euro]

OK. PMs exchanged. I'll report back.

That's great! Now, if you just post your mailing address here then we can all send our 110v electric projects? Would you consider travelling onsite for stationary projects?

 

[OldShooter]

That's great! Now, if you just post your mailing address here then we can all send our 110v electric projects? Would you consider travelling onsite for stationary projects?

No problem!

$1000/day including travel days, plus expenses, 3-day minimum. Lead time on mailed-in projects may range from 10 days to forever. Fees double if customer helps or wants to argue investment strategies. Fees triple if customer believes he can time markets.

 

[ERD50]

.... As mentioned above it is important to have the correctly rated fuse. The majority of devices here including lamps require a 3 amp fuse, and only high current appliances such as kettles, toasters etc come with 13 amp fuses. ....

Ahhhh, yes - this is another difference in UK style plugs, they have a built in fuse, uncommon in US style plugs.

I think the UK approach is better/safer. And it is why (despite some protestations from someone with an MSEE), I mentioned that there is a chance that the lamp wire may be a small gauge, and could, under an internal short circumstances, create an unsafe condition where the wire could get hot and start a fire, or other heat damage before the panel circuit breaker would pop.

An exception in the US, which will make this clear to all, are the little holiday lights we use (either LED or small glass filament bulbs). Those use small wires, to make it easier to decorate (and cheaper). And you will notice, these do have two tiny fuses in the plug connected to each of the two prongs. That is for the exact reason I mentioned - if there was a short somewhere along the wiring, that small wire could get very hot (similar to the heating coils in a toaster) and create an unsafe condition. The plug fuses help to protect against that. Small wires without a plug fuses can be a hazard.

You could possibly have a similar situation with that lamp. As Alan says, 3 amp fuses are common on UK lamps - so it is likely that they don't bother rating that wiring for much more than 3 amps, and it will be plugged into a 15A circuit here in the US! Safety first, always. No one should be giving this very real concern short-shrift, especially an MSEE who has experience with house wiring. Sorry, but I will not "hold my tongue" when it comes to personal safety.

But replacing everything, and bringing all components up to compatibility with the way things are done in the US, as mentioned several times in this thread by several people, is a safe approach.

-ERD50

 

[meierlde]

Actually if your concerned once you cut the old plug off you can measure the size of the wire at the end of the cut section, then go to a table of us wire sizes and if its size 16 or 18 it should be ok.

As an alternative you could of course buy an international adapter and plug the lamp into it, but you would have to find 220v lamps (amazon.uk likley)

 

[ERD50]

Actually if your concerned once you cut the old plug off you can measure the size of the wire at the end of the cut section, then go to a table of us wire sizes and if its size 16 or 18 it should be ok. ...

Agreed. -ERD50

 

[OldShooter]

... No one should be giving this very real concern short-shrift, especially an MSEE who has experience with house wiring. Sorry, but I will not "hold my tongue" when it comes to personal safety. ...

Too much misunderstanding here to deal with, but why don't you check the wire size on some of your plug-in lights, wired-in lights, and ordinary extension cords? House wiring in 15 amp circuits is #14AWG, 20 amp circuits are #12AWG. Report back if you find anything except heavy duty extension cords with wire this heavy. Hint: HD cords use 14/3 or even 12/3 to reduce voltage drop, not for "personal safety."

 

[ERD50]

Too much misunderstanding here to deal with, but why don't you check the wire size on some of your plug-in lights, wired-in lights, and ordinary extension cords? House wiring in 15 amp circuits is #14AWG, 20 amp circuits are #12AWG. Report back if you find anything except heavy duty extension cords with wire this heavy. Hint: HD cords use 14/3 or even 12/3 to reduce voltage drop, not for "personal safety."

Trust me, I did that before I made that original post, just to 2x check my understanding.

I didn't find anything smaller than 18 AWG (unless it had a plug fuse, like the Christmas Lights). Sure, that is less than the house wiring standard, but they are only 6 ' long, and they aren't inside walls. The spec for that case can be looser, voltage drop isn't a concern as it would be in long house wiring.

Are you saying you can find a 3 amp rated cord attached to a UL approved device for North America?

-ERD50

 

[ERD50]

Just another reference point on these wire gauge and cord safety issues, to make it more understandable to others:

A typical desk lamp might commonly be rated for a max 60 W old-style filament bulb. We've probably all seen those labels right?

Well a 60 Watt bulb draws only ~ 1/2 Amp. So the cord would really only need to be rated for that to supply the bulb. Even a tiny 32 AWG wire is rated for that much current. And a 32 AWG wire is only 0.008 inches in diameter - tiny indeed (that's the diameter of the copper wire, insulation would be additional). A 32 AWG wire is about the size of a typical single strand from a typical multi-strand power cord - you know, one of those tiny little wires in the bundle of wires that make up the cord.

But these lamps have much heavier cords - to be able to handle the 15 A from the wall until the breaker pops, in case of a short in the cord/appliance.

https://en.wikipedia.org/wiki/American_wire_gauge


-ERD50

 

[AllDone]

Wow!

However, that is a really pretty lamp and I can see why you bought it.

 

[meierlde]

Just another reference point on these wire gauge and cord safety issues, to make it more understandable to others:

A typical desk lamp might commonly be rated for a max 60 W old-style filament bulb. We've probably all seen those labels right?

Well a 60 Watt bulb draws only ~ 1/2 Amp. So the cord would really only need to be rated for that to supply the bulb. Even a tiny 32 AWG wire is rated for that much current. And a 32 AWG wire is only 0.008 inches in diameter - tiny indeed (that's the diameter of the copper wire, insulation would be additional). A 32 AWG wire is about the size of a typical single strand from a typical multi-strand power cord - you know, one of those tiny little wires in the bundle of wires that make up the cord.

But these lamps have much heavier cords - to be able to handle the 15 A from the wall until the breaker pops, in case of a short in the cord/appliance.

https://en.wikipedia.org/wiki/American_wire_gauge


-ERD50

Actually if you go to Lowes or Home Depot you see 16 and 18 gauge wire used in lamp cords. The web seems to be divided between 16 and 18 guage, but talks 16 beyond 25 foot. As pointed out led lights at a max of 25 w draw 1/4 amp. the issue in the past is that folks would plug a 1500 watt space heater into a #18 extension cord which is a no no. If there is a short the current will be far above 15 amps, so its the fact that the short would only last a very short time. The idea is that a lamp typically has a 8 foot or less cord so apparently #18 works. Here is a link to a guide for selecting light duty extension cords, (and thus wire guage) https://www.thespruce.com/select-proper-electrical-extension-cord-1824710 note for lamps, clocks, up to 7 amps total up to 25 feet 18 guage is ok. 16 for 50 feet etc.

 

[OldShooter]

... for lamps, clocks, up to 7 amps total up to 25 feet 18 guage is ok. 16 for 50 feet etc.

Yes. The major consideration for cords is voltage drop, which is linear with specifid resistance, linear with current and linear with length. Incandescent light bulbs just get dim with low voltage, but trying to operate a motor below its rated voltage can be problematic. Specific resistance goes down with increasing wire diameter, which allows length to go up.

There is actually no such thing as an "amp rating" for a piece of wire. Carrying capacity depends on its environment (free or packed in with other wires, for example), type of insulation (heat resistance), and ambient temperature. The code sort of wraps all of these issues together to develop a simple-to-use concept called "ampacity," but it is really a one-size-fits-none kind of concept.

Interesting Factoid: The conductors in high-voltage distribution systems (aka "the grid") actually heat up enough that wire sagging limits current carrying capacity in the summer.

 

[Clone]

OK the process for the physical modifications have been set in place.

I somebody going to weigh in on which operating system to install?

 

[atmsmshr]

Alas, I am afraid this may be the case. I was wondering why I couldn't seem to remove the socket.

As it turns out, there is a UK electric regulation that requires socket bases to be affixed at no less than 2 Newton meters torque.

In case I missed the answer asked, it is it a standard USA screw socket or some fiddle bayonet type bulb base?

All engineering aside, the lamp is gracefully designed.

 

[Bryan Barnfellow]

You worked in a much more efficient place. We would have the engineering meeting and that would spawn a tiger team to figure out the best solution. The ISO guru would hear about the project for which we did not have defined process and start a ISO effort to define the process for this new effort. After killing an acre of trees for the process documentation the quality lead would pick up their coffee cup an see the brown coffee ring and declare that was the brown circle of quality. We would leave and no one remembered about the tiger team or the engineering issue the started the whole effort. Soon someone would come up with an idea that would generate the next tiger team and the death of more acres of trees.

All of this reminds me of the documentation manual for an early database program (in very early shrink wrap form) in 1983 for the new IBM PC. Their blank pages between chapters all said, "This page unintentionally left blank." After trying desperately to make that package work for a client, I began to believe it!