For this 240v harbor frieght spot welder what should be the breaker size?
Spot welder breaker size?
- Thread starter wazzabie
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It's rated at 16 amps. I would use a 20 amp breaker.
nadogail
Well-known member
My Stick Welder is fed from a 50 Amp breaker and #8 wire.
mike93lx
ALLIANCE MEMBER
The manual doesn't specify a required breaker size, so 30 should be fine. What plug end comes on it?
i'd expect its either a 6-20 or a 6-50 (to match most welders). You should not have a 20a receptacle on a 30a circuit breaker.
are you trying to repurpose an existing circuit?
i'd expect its either a 6-20 or a 6-50 (to match most welders). You should not have a 20a receptacle on a 30a circuit breaker.
are you trying to repurpose an existing circuit?
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And my refrigerator is in a 20A circuit.
WTF does this have to do with the OP's question?
I'd run 12/2 and breaker at 20A.
If I thought I might ever run a larger mig or stick I might put the appropriate wire for that and breaker lower.
toolenthusiast
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Tangential question: what is that spot welder even good for? The only thing I know of that commonly gets serviced with spot welds is auto bodies, and you certainly wouldn’t weld on a car with those tiny little pointy electrode caps. Do people use it for light duty fabrication?
Mike in post #5 hit the nail on the head. The breaker is designed to protect the other elements of the circuit (recepticle, wiring, connectors) and to some extent, the equipment plugged in to it. If the wiring or the recepticle are not sized for 30 amps, but you use a 30 amp breaker, you risk damaging your circuit. If your device plug is not rated for 30 amps, and you use a 30 amp breaker, you risk damaging your device.
The idea is to use the smallest breaker you can (which should be rated lower than everything else in the circuit) that will still handle the load you will draw.
All that said, assuming the plug will physically fit the recepticle, it will work.
seber
Well-known member
You will need a 20 amp circuit minimum. Breaker size is rated by the wire size, not the unit you plug into it.
Jim greengo
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Except for hvac equipt.
From the factory there is no plug.
I have an existing dedicated 30amp circuit that I would like to repurpose.
mike93lx
ALLIANCE MEMBER
If you don't want to.make the plug available for other welders, I'd probably put a 6-30 on it.
If you want it to be usable for other welders, use a 6-50.
rsanter
Well-known member
I have the miller version of that.
I use the same 30amp cuicuit I use for the Mig/TIG
I use the same 30amp cuicuit I use for the Mig/TIG
toolenthusiast
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I guess none of the wise electricians in this thread have an answer
mike93lx
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Did googling for it let you down?I guess none of the wise electricians in this thread have an answer
Isn't 125% of 16 = 20?
Generally, you should size a breaker for 125% of the load (or 25% extra capacity) and no less. Oversized breakers can allow wires to heat above safety levels without stopping the current. On the other hand, undersized breakers may continuously trip under normal operation.
www.omnicalculator.com
Generally, you should size a breaker for 125% of the load (or 25% extra capacity) and no less. Oversized breakers can allow wires to heat above safety levels without stopping the current. On the other hand, undersized breakers may continuously trip under normal operation.
Breaker Size Calculator
The breaker size calculator will help you obtain the correct circuit breaker size for your home panel based on the electrical load.
www.omnicalculator.com
mike93lx
ALLIANCE MEMBER
Yes, that would be the minimum required circuit size, not a maximinum. If using a 30a, the wiring had to match that ampacity, which in nm-b, is #10. 12 nm-b with a 30 would not be okIsn't 125% of 16 = 20?
Generally, you should size a breaker for 125% of the load (or 25% extra capacity) and no less. Oversized breakers can allow wires to heat above safety levels without stopping the current. On the other hand, undersized breakers may continuously trip under normal operation.
Breaker Size Calculator
The breaker size calculator will help you obtain the correct circuit breaker size for your home panel based on the electrical load.
So I can plug a 30 amp heater into a 50 amp breaker and that's safe depending on "wire size".
mike93lx
ALLIANCE MEMBER
If the wire is sized for the load and the device doesn't require the breaker for it's own protection, yes.So I can plug a 30 amp heater into a 50 amp breaker and that's safe depending on "wire size".
How about all those lamps in your house plugged into 20a circuits? Run 20a through that cord and it will get toasty fast
Not necessarily when it comes to welders. NEC Article 630 covers the topic and allows for conductors to be generally undersized for a given breaker size when compared to normal residential wiring.
toolenthusiast
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Yes. Did you google it? Because ya know what comes up? The HF page and a GJ thread talking about… drum roll, please… the fact that they aren’t really suitable for anything.
Thanks for pointing that out. Maybe you could provide some specifics that would steer the OP in the right direction given their specific situation if different than has been generally discussed here so far? While some folks are willing/able to read/understand/implement the guidance in the NEC, I feel like that's probably not universal.
mike93lx
ALLIANCE MEMBER
Spot Welder Applications
For those who think it's easier to annoy you than to Google 'Spot welder applications' themselves.
toolenthusiast
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I know what a spot welder is. I have a spot welding certification. How’s your reading comprehension?Spot Welder Applications
For those who think it's easier to annoy you than to Google 'Spot welder applications' themselves.letmegooglethat.com
If you have a spot welding certification, why are you asking a bunch of "wise electricians" what they are good for?
toolenthusiast
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Without knowing more about the OP's setup there really isn't any way to give more specific advice. We would need to know the wire size and type, length of run (probably not a factor, but just to be safe) and then the outlet/plug setup intended.
I was just pointing out that the blanket statements weren't necessarily true and mentioning the NEC article in case anybody wanted to do their own research.
If the OP's 30a circuit has the 10ga wires you would expect I can't see it causing a problem. The machine only draws 16a max and isn't close to being a continuous load, so it wouldn't seem likely that it could overheat the wires and cause a fire hazard. If we were talking about something like a compressor that could potentially wind up running continuously by accident it would be a different discussion.
For sure, but Are the lamps pulling 20 amps?
If not, wouldn’t that be why the cord is not necessarily heavy?
Something that could pull 20 amps probably has a heavier cord, right?
mike93lx
ALLIANCE MEMBER
I'm confused on how that's different than your example.
Back in the golden age of military surplus after the iron curtain fell they were used to weld the rails on the receiver when building a semi auto AK47 from a parts kit. The tongs were modified to fit into the receiver.
The parts kits all dried up, and the government banned the importation of barrels for "non-sporting" rifles, so this isn't much of a thing anymore.
The parts kits all dried up, and the government banned the importation of barrels for "non-sporting" rifles, so this isn't much of a thing anymore.