UK welder to US circuit

[Zeke]

Hey guys, I copied the text of a post on the Porsche forum known as Pelican Parts. My friend over there asks (http://forums.pelicanparts.com/off-topic-discussions/737881-need-electrician-230v-questions.html):

I've come upon an odd situation.

My friend moved here from the UK and gave me his MIG welder that he had shipped over here because he didn't have a place to use it. It's meant for UK power, so it is 230v with a 13 amp rated heavy duty plug with a ground, a load wire, and a neutral wire. So I understand it that in the UK, there is a 230v-240v 50hz feed on that load wire, return to 0v on the neutral, and ground is ground. The machine claims it can take a 50 or 60 hz frequency.

I have a step up transformer that I use for my coffee machine from Germany, but it can only do 2000 watts, which I have used to weld with this MIG machine but the transformer is topped out and sounds like it doesn't like it. It was expensive, so I'd rather not burn it out.

So I am wondering- could this MIG be wired up to either side of a US 230v outlet- from a dryer/range plug? On those, again, as I understand it- there are two load wires and one neutral and no ground. The two loads are 115v each, but out of phase with each other which would make 230v across the two. If I wired the UK MIG welder's load wire to one of these 115v, and the UK neutral wire to the other 115v, would this work? Then the nuetral return line would not be connected to anything. I have read about people doing this with heater kettles and such but not something with a transformer in it like a welder. And then my next question is what to the with the case ground- I checked, the ground from the welded just bolts to the outer case, so I'm assuming I could just tie it to a wall panel screw to ground it.


Do I have this right? Any concerns? I know it's not 'to code' but that's not something I am concerned about. Breaker gets shut off for and everything unplugged whenever I'm not using it anyway.

Can you guys sort this?

 

[MoonRise]

The machine don't really care what shape the wall outlet is.

Just feed it the 'right' power (voltage, amperage, and AC frequency) on the wires and the machine will run.

If the machine can accept 50 Hz or 60 Hz power, then that part of the power input is no problem. One down, two to go.

For amperage, just make sure that the 'wall' side of things can feed enough amps to the machine (safely, don't overload the circuit breaker or the wiring, shouldn't be a problem if going from a UK 13-amp 230V circuit to a US 230-240V 20+ amp dryer circuit) to keep it 'happy'.

Two input power conditions satisfied, one to go ...

If the machine is looking for ~240V AC between two input wires, then just feed it 240V.

If the ground wire on the machine's original cord just goes to a ground screw on the inside of the machine, that's good and 'normal'.

If the desired outlet to feed the welder is a standard US 4-wire dryer outlet (hot, hot, neutral, ground), just snip off the UK plug and get a replacement US 4-wire dryer plug. Connect the three wires on the welder's power cord into the replacement plug with ground-to-ground and the other two wires of the power cord to the 'hot' prongs in the plug. Don't connect anything to the 'neutral' prong on the plug.

If the desired outlet to feed the welder is a standard (older style) US 3-wire dryer outlet (hot, hot, ground), just snip off the UK plug and get a replacement US 3-wire dryer plug. Connect the wires on the welder's power cord into the replacement plug with ground-to-ground and the other two wires of the power cord to the 'hot' prongs in the plug.

Plug the US-ified power cord into the US dryer outlet and weld away.

 

[Zeke]

Moon, that is helpful, but what Mike wants to know is if the welder is ready for US 240, i.e., 2 legs of 120v.

 

[Charles (in GA)]

The machine don't really care what shape the wall outlet is.

Just feed it the 'right' power (voltage, amperage, and AC frequency) on the wires and the machine will run.

If the machine can accept 50 Hz or 60 Hz power, then that part of the power input is no problem. One down, two to go.

For amperage, just make sure that the 'wall' side of things can feed enough amps to the machine (safely, don't overload the circuit breaker or the wiring, shouldn't be a problem if going from a UK 13-amp 230V circuit to a US 230-240V 20+ amp dryer circuit) to keep it 'happy'.

Two input power conditions satisfied, one to go ...

If the machine is looking for ~240V AC between two input wires, then just feed it 240V.

If the ground wire on the machine's original cord just goes to a ground screw on the inside of the machine, that's good and 'normal'.

If the desired outlet to feed the welder is a standard US 4-wire dryer outlet (hot, hot, neutral, ground), just snip off the UK plug and get a replacement US 4-wire dryer plug. Connect the three wires on the welder's power cord into the replacement plug with ground-to-ground and the other two wires of the power cord to the 'hot' prongs in the plug. Don't connect anything to the 'neutral' prong on the plug.

If the desired outlet to feed the welder is a standard (older style) US 3-wire dryer outlet (hot, hot, ground), just snip off the UK plug and get a replacement US 3-wire dryer plug. Connect the wires on the welder's power cord into the replacement plug with ground-to-ground and the other two wires of the power cord to the 'hot' prongs in the plug.

Plug the US-ified power cord into the US dryer outlet and weld away.

^^^Exactly^^^

The "neutral" in our system is a current carrying wire, just like any other, except that it is grounded to protect the system since it is tapped off the center of the transformer.

A UK 230v power system is no different that a US 240v power system, both are tapped off the ends of the transformer.

Put a US plug on it and it will work fine, will never know the difference.

Charles

 

[Norcal]

The machine don't really care what shape the wall outlet is.

Just feed it the 'right' power (voltage, amperage, and AC frequency) on the wires and the machine will run.

If the machine can accept 50 Hz or 60 Hz power, then that part of the power input is no problem. One down, two to go.

For amperage, just make sure that the 'wall' side of things can feed enough amps to the machine (safely, don't overload the circuit breaker or the wiring, shouldn't be a problem if going from a UK 13-amp 230V circuit to a US 230-240V 20+ amp dryer circuit) to keep it 'happy'.

Two input power conditions satisfied, one to go ...

If the machine is looking for ~240V AC between two input wires, then just feed it 240V.

If the ground wire on the machine's original cord just goes to a ground screw on the inside of the machine, that's good and 'normal'.

If the desired outlet to feed the welder is a standard US 4-wire dryer outlet (hot, hot, neutral, ground), just snip off the UK plug and get a replacement US 4-wire dryer plug. Connect the three wires on the welder's power cord into the replacement plug with ground-to-ground and the other two wires of the power cord to the 'hot' prongs in the plug. Don't connect anything to the 'neutral' prong on the plug.

If the desired outlet to feed the welder is a standard (older style) US 3-wire dryer outlet (hot, hot, ground), just snip off the UK plug and get a replacement US 3-wire dryer plug. Connect the wires on the welder's power cord into the replacement plug with ground-to-ground and the other two wires of the power cord to the 'hot' prongs in the plug.

Plug the US-ified power cord into the US dryer outlet and weld away.

There is no ground on a 3-wire dryer or range plug, it's a neutral.



A UK supply is 240V ( EU harmonized as 230V but still 240V) line to neutral, a domestic 240V is line to line, there should not be any problems as long as it's rated 50/60 Hz.

 

[Zeke]

Norcal, I see what Charles is saying. Fine line, technically.

 

[tfi racing]

Moon, that is helpful, but what Mike wants to know is if the welder is ready for US 240, i.e., 2 legs of 120v.

Nope,its not gonna work that way.He needs to get a larger transformer,or if he is lucky the machine has the capability to be switched internally to our North American system.If it was a simple resistive load(ie heater) it may be possible,but in this case the electronics of the welder will definitely NOT be happy...

 

[Charles (in GA)]

Nope,its not gonna work that way.He needs to get a larger transformer,or if he is lucky the machine has the capability to be switched internally to our North American system.If it was a simple resistive load(ie heater) it may be possible,but in this case the electronics of the welder will definitely NOT be happy...

Not sure where you are coming from. 240v AC is 240v AC, plain and simple. He is not wanting to run it on 120v, but just wants to know if it will work on 240v (improperly described as two 120v legs). We have been told it is a 50/60 Hz unit, so the cycles are not a problem.

Charles

 

[MoonRise]

There is no ground on a 3-wire dryer or range plug, it's a neutral.


A UK supply is 240V ( EU harmonized as 230V but still 240V) line to neutral, a domestic 240V is line to line, there should not be any problems as long as it's rated 50/60 Hz.

Yup, 'older' 3-wire range/dryer is hot-hot-neutral (NEMA 10-30 or 10-50). Brain-fart on my part, was thinking 'welder' all along and pictured NEMA 6-30 or 6-50 configuration (hot-hot-ground).

Zeke, if the machine is a 50/60 Hz machine and is 'fed' 230-240V AC on the input wires, it will work.

The machine don't care if the plug/receptacle is UK-spec or US-spec, just feed it 230-240V power on the input wires.

The ground wire (or lug or blade) goes to the ground wire. The 'other' two wires (or blades or lugs) on the machine get fed 230-240V power.

 

[bd8134]

I did exactly that with my UK tools and appliances and they work great.
For inside the house I used to use a step-up transformer to convert 120v to 240~220v.
I used this for vacuum cleaners, smaller electric drills etc.
For my garage I wired in additional 220v sockets. I used to have a Clarke mig welder from the UK until it bit the dust. I run my pillar drill, Bosch hammer drill, hand grinder, heat gun, even my fair sized air compressor, all from the UK.
I read that you might hear a buzzing from some coils inside the appliance, but I have never noticed it, because of the different hertz. There might be also slightly less power because of the voltage also.

 

[RustFarmer]

What happens if the welder's main power switch is single pole? Turn it off, and you still have 120v coming in on the "neutral".

 

[tylernt]

What happens if the welder's main power switch is single pole? Turn it off, and you still have 120v coming in on the "neutral".

True, it'll be a shock hazard to anyone touching the innards, but as long as it's properly grounded, it should not be a huge fire or life safety issue.

Probably not code though.

 

[Norcal]

A single pole switch is fine for a 240V load but it would not be acceptable for a disconnect.