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Tying 2 plugs together on generator.

Portable Welder

Cast Iron
Joined
Jan 9, 2015
Location
Milan, MI
I'm buying a a 17,500 watt Generac generator that puts out approximately 78 amp 230v the largest plug is a 50 amp and it also has a 30 amp outlet, while I will use this to run my shop during power outages, I also want to use it to run my Dynasty 300 tig welder to do portable tig jobs.
The tig draws 61 amps single phase, so my thoughts would be to tie both plugs together obviously keeping both matching phases together.

I looked at the wiring diagram and the phases are together on the inside.

Based on them both being fused, one at 30 amp and the other being 50 amp, I think the 30 amp breaker would pop when I hit 60 amps of draw but that would get me where I need to be for the tig welder.

Since plugs bigger than 50 amps are very rare and very expensive, I might have to use a disconnect switch to carry the additional amps.

So what should my worries be ?
 

pavt

Stainless
Joined
Jun 30, 2013
Location
20 miles north of Buffalo NY
No reason why you couldn't use a 3-phase hi-amp plug, but it will cost. You cheapest bet is to just hard-wire it with a breaker panel. BUT -- how often do you kick it wide open and actually use all 60 amps from the AC power?? Sure you can't get by with less? I used to run a syncrowave 250 and it was rare if I had to go over 180 welding amps (water-cooled)
 

Just a Sparky

Hot Rolled
Joined
May 2, 2020
Don't f*ck around with paralleled plugs.

Retrofit the generator for use with single pole cam connectors. This is how mobile generator sets are connected. Good for 400A depending on the size you buy. Install a combiner box on the welder. Either wire it for generator power exclusively or install a manual transfer switch or key interlock to prevent backfeeding and the creation of a 'suicide plug'.

Connectors | Single Pole Cam-Type | Product Catalog Search Results | Galco Industrial Electronics
Single Pole Cam Type Connectors High Power | Duraline
https://www.leviton.com/en/docs/Q-934D_15_16_18_Series_UL1691_Compliant_Connectors_PB.pdf

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Also as mentioned above, my 250 amp buzz box calls for 70 amps on the primary... but it runs happily on a 40A circuit all day long because I never need more than 150 welding amps. If you're not going to be pushing 300 welding amps on your TIG machine, then just try it as-is and see what happens. You might find the existing arrangement suits your needs adequately. Thermal trip elements exist in circuit breakers to allow for 'harmless' overloads which neither persist for long nor cause dangerous overheating of circuit conductors.
 

JST

Diamond
Joined
Jun 16, 2001
Location
St Louis
Those connectors are the deal. Work well, no BS, just get the right ones where they go. Even a traveling ride carny man can do it. Most of them use those.

Beats heck out of a $300 one piece connector. Available for large amperages.
 

EPAIII

Diamond
Joined
Nov 23, 2003
Location
Beaumont, TX, USA
Circuit breakers are not intended to be wired in parallel and there is absolutely no way of knowing just how two different sized breakers would divide the current. It could be as bad as the smaller, 30A breaker would try to pass the lion's share and pop when your total draw reached 35A or less. And even if you have seen something like that work, there is absolutely no way of knowing if your particular pair of breakers would work the same way or entirely different. I would not do it.

I would do as Just A Sparky suggests. Install a changeover switch and a single, 70A or 75A breaker on that switched circuit. With a total of 78 A capacity, a second, 15A breaker could be added to the switched circuit to allow some shop lights to be lit. You would be moving light cords back and forth as you switch to and from the welding mode.
 

Phil in Montana

Stainless
Joined
Jul 31, 2007
Location
Missoula Mt
You are in la la land if you think a17,500 watt Generac generator will make 17.5 kva... You will not get 14kva out of it, big piece of doggy do dont buy it...Phil
 

Rob F.

Diamond
Joined
Aug 5, 2012
Location
California, Central Coast
Will you be running that machine at MAXIMUM power? 50 amp will probably be fine if you are not running at max. you could put an amp meter on the input cord to see what your real power draw is.
 

DDoug

Diamond
Joined
Oct 18, 2005
Location
NW Pa
I'm buying a a 17,500 watt Generac generator that puts out approximately 78 amp 230v the largest plug is a 50 amp and it also has a 30 amp outlet, while I will use this to run my shop during power outages, I also want to use it to run my Dynasty 300 tig welder to do portable tig jobs.
The tig draws 61 amps single phase, so my thoughts would be to tie both plugs together obviously keeping both matching phases together.

I looked at the wiring diagram and the phases are together on the inside.

Based on them both being fused, one at 30 amp and the other being 50 amp, I think the 30 amp breaker would pop when I hit 60 amps of draw but that would get me where I need to be for the tig welder.

Since plugs bigger than 50 amps are very rare and very expensive, I might have to use a disconnect switch to carry the additional amps.

So what should my worries be ?

Apparently you like to saturation bomb this forum ?....:nutter:

Don't cross post.

Generator to run tig welder
 

James H Clark

Stainless
Joined
May 11, 2011
Location
southern in.
I agree with Phil in Montana about the Generac's. I have a smaller one (8000-12000) and it is a piece of crap. Breakers and plugs are junk. Generac factory is no help. Don't do it.
JH
 

thermite

Diamond
I agree with Phil in Montana about the Generac's. I have a smaller one (8000-12000) and it is a piece of crap. Breakers and plugs are junk. Generac factory is no help. Don't do it.
JH

I thot all Generac actually "manufactured" was the sales literature and "Generac" labels to slap onto the latest shipment of lowest-bidder goods?

So which "factory?"

Mind not new. My MEP803a is a "Fermont". The bid contractor. The Diesel is now presented as a Cummins, Onan division.

In real life it is an old-reliable Marathon head on an old-reliable liquid-cooled Lister-Petter 4-hole anything- that-resembles-Diesel-or-not-even burner.

I think the only hydrocarbons in MIL inventory that are NOT on the fuel list is that toenail fungus paint and bunker C?

Fuel tank & gauge sucked, but that wasn't hard to improve.
 








 
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