Flexible cable requirements Miller 452

[lynnbilodeau]

Bought a lightly used Miller Dimension 452 from a local votech.
It is currently set up to run on 480 three phase. My new shop has 400 amp service, with 208 three phase available.
Electrician has run a dedicated fused 125 amp circuit to the welder location, with a separate shut off next to the main breaker box. #2 wire run from that shut off to the second shut off by the welder. Will run an outlet from that shut off for the welder to plug in.

I already know that I need to re-arrange the jumpers per section 5-11 on page 23 of the manual.

The current power cord is four wire #8 flexible cord.

I THOUGHT I read on the Miller site that the unit would normally draw about 80 amps with heavy use. But looking at the chart on page 23 (section 5-10) looks like it will draw 104 amps.

I know I need to purchase a new plug end for the power cord, and a receptacle. Two questions:

1. Can I re-use this cord? Looks to me like I need a four wire with #2 flexible cable. Seems awful big. Is that correct?

2. What plug and receptacle do I need to purchase?

I realize you welders and professional electricians will just be laughing. I am decent with car electrical issues; in the dark here.

 

[u2slow]

Read your miller manual for the cord size they recommend for the machine. Its usually less than full ampacity due to duty cycle. You're probably into costly pin & sleeve type connections with that size.

You could check on the single-conductor stuff used in the movie industry. This page shows some examples: https://setlighting.tumblr.com%2Fpost%2F151063840141
Another route I would consider is a step-up transformer to 480V in order to have a smaller cord.

 

[Walkers]

You could also ask yourself what you would be welding to max out that machine at those amps. I weld every day and it is pretty rare for me to have my machines turned up that high. TIG welding 1/2 and 3/4” plate, heavy spray arc, and 1/4“ welding rods do require some big amps, but most people don’t weld that heavy.

 

[wyliesdiesels]

you will need Pin and sleeve plug and receptacle. standard NEMA plugs will not work here.

or get a 480v step up transformer like suggested and leave the welder setup the way it is

 

[Walkers]

If you are wanting to keep it mobile just use a NEMA 14-60, again, so long as you aren’t welding super heavy you should be fine. Put in 60 amp fuses so you don over amp your pigtail or outlet.

 

[lynnbilodeau]

Thanks all for the input.

 

[lynnbilodeau]

Wanted to post the final solution for this. Hate when threads are just left hanging.

Bought Leviton pin and sleeve outlet and plug that was rated for the full capacity of the welder. I won't LIKELY every be using this at full capacity, but who knows. Kind of pricey. Ended up spending about $700 on the plug and receptacle, and another 60 bucks on a separate box and rigid conduit, as the receptacle was too large to fit into the switch box without a mod that would have compromised the UL listing for the box. Would rather err on the side of overkill, especially when it comes to safety. I will post some pics of the install; all done by a licensed electrician with required permit. My electrician was doing this as a side job, but all is top notch. He does mostly general very large commercial type stuff (hospitals, casinos, etc.) but no prior experience with an Automotive type shop. That's why I came here for some assistance.

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I cannot tell you guys how much I appreciate this web site. Yea, just like everywhere else, there are a few abrasive folks, but I ALWAYS know that when I come here with a hairbrained idea or odd ball question, there will be folks willing to assist. Now it is time for me to get off my fat *** and go get some work done on my new workshop so I can start working on my cars again. I have enough projects lined up to keep me busy until I am 90.

 

[EasyE]

Is hard wiring it to a 100 amp disconnect against code? Thats how my 451 is wired in my shop....