Plasma, electrical, home wiring, OH MY!

[SeanP]

Well, the UPS guy dropped of my new toy yesterday. A new Hypertherm 1250 80 Amp plasma. Now I need to get my garage wired for it.

I have single phase power at home. I am pretty sure there is no way to get 3 phase power (electrical newbie here, bear with me). Hypertherm says that the peak amp draw at startup on the highest setting for single phase (plasma can do both) is 96 AMP

I am pretty sure my box is 200 AMP service. How hard will it be to run a singe 100 AMP circuit in the box? My calculations for about 25-50 feet of wiring is that I need to use 6 guage wire.

Who else has run a fat plasma at home with single phase current? Any tips or tricks?

Thanks

SeanP

[D60]

Um, wow! 96A. What sort of 220 outlets are even rated for that?

6 ga seems a bit small?

If you wanna do longer runs that's gonna get costly. All my 220 outlets are 50A for the plasma, IIRC I used #6 THHN, and my longest run was ~70ft

so I guess I'm not much help but keep us updated

[rusted]

I'm only aware of a 50amp outlet. Do you have a pic of your plasma's plug? Or can you tell us, is it the same plug on your 220v welder (if you have one?)

I would check some more around Hypertherm's site for circuit reccommendations.

She'll draw that 96amps at startup, then settle down. Your circuit breaker will not trip, all the NEC tables, specifications for overcurrent devices, and specs for conductors, take into account peak current draw.

So I would wire a 50 amp circuit with what I will guess is the standard 50amp 3 prong outlet and go for it.

Again, I know we've had this discussion before, but I wouldn't consider #6 for anything over 20' or so. Look at it this way. IF it turns out you need some type of bigger outlet, wire it for that first. You could have a 4/0 service entrance cable with a 50 amp plug and overcurrent device (breaker). No problem to OVER spec the conductor, big problems if it's underspecced.

The only 6ga conductor I've got left in the house is the 3' run from my subpanel to the welder outlet. My house is wired like a brick shithouse now, I don't know if those were ever wired, but my house is heavy duty.

You won't get 3ph power.
You probably have 200amp service. I tried to get 400, but they demurred. My freidn who works for the PUD up in WA has 400amp service, lucky bastard.

[DRM]

Originally Posted by D60

Um, wow! 96A. What sort of 220 outlets are even rated for that?

None that I am aware of that would even remotely be considered common use.


I think Rusted covered it pretty well

[D60]

Originally Posted by DRM

None that I am aware of that would even remotely be considered common use.

I was wondering if maybe you could find some sort of a mobile home or RV plug? But most RV's are 50A. Old mobile homes were 50A, now they're 100A, but I've never seen a plug on a mobile home for the main power feed.

[rusted]

Originally Posted by D60

I was wondering if maybe you could find some sort of a mobile home or RV plug? But most RV's are 50A. Old mobile homes were 50A, now they're 100A, but I've never seen a plug on a mobile home for the main power feed.

Well yeah mobile home outlets are common, but they're not for appliances, and Hypertherm certainly didn't put one on their unit. I don't THINK anyway.

Here's that table. If it's a factory setup, you find what plug it has, then wire your outlet appropriately, and you'll be fine.

What I mean is if it's got a 50amp plug, then put in a 50amp outlet CORRECTLY, and that's it.

[SeanP]

thanks for the responses. There is no plug on the unit, just stranded wire to add whatever plug you need. I have an electrician friend coming over this weekend to set it up correctly. Sure it will cost some money, but it's worth it as I set up my business. Custom CNC plasma work, who wants some?

SeanP

[Eric]

Usually anything over 50A should really be hard wired to the circuit breaker.
To run this unit on 230V or 240V input would require a 75A breaker (60A x 1.25) and probably 4 AWG THHN wire for short runs.

[Gummi Bear]

The only receptacles you'll find that are rated for greater than 50A are going to be of the 400Hz variety (for aeronautical use, BIG $$$) You won't find them on a NEMA config chart either. Look in your instruction book, or on the name plate of the plasma cutter. There should be a spot that says Max Fuse Size, or even Recommended Circuit Size. That's what you'll base your circuit and overcurrent protection off of. The 96A load is just an inrush current, the same thing that an arc welder does, it is not a sustained load, and therefore does not tax the circuit, allowing you to derate your wire size.



BTW - #2 is what you'd want for a 96A load (look in the 75* column of T310-16) I'm pretty sure that's not the case.

According to this:

Hypertherm Owners Manual on the Website

It looks like you'll need a 60A circuit at 230V single phase. You can find a 14-60 P cord cap and the coordinating 14-60R receptacle if you choose to have a cord and plug connected setup.

NEMA Config chart, showing a receptacle that will work just fine

Hope this helps.

[frankenfab]

The manual should have a recommendation for the size of over current protection.

Usually, something like that would be hard wired to a fused disconnect.

[jasonmt]

My Miller 3080 (80Amp) runs alright off of 50A single phase service at home. In the field it runs off of the 30A 3 phase power from the engine drive. I would give it a go with 50A to start and see if it works for you.

[jasonmt]

Originally Posted by frankenfab

The manual should have a recommendation for the size of over current protection.

Usually, something like that would be hard wired to a fused disconnect.

Just to illustrate I previously snapped this picture: A 4Pack of Miller Dimension 452's which need ~90A @ 230V 3Phase. Notice the hard wired/fused configuration.

[eb76adam]

Originally Posted by frankenfab

The manual should have a recommendation for the size of over current protection.

Usually, something like that would be hard wired to a fused disconnect.

frankenfab - doin me right - show off those square d goods.
I've got a quota to make.

[Hammerlock]

I have the 1250. 100 amps is over kill. 50 will work. 75 recommended.

[steveh]

Sean. looks like the general consensus is to hardwire it to a safety disconnect. I concur. Devices that can draw that kind of current don't use receptacles.

It's not a difficult job to add the breaker and do the wiring most of the time. Sounds like your panel is close to where your gona set up the machine.

PM me if you want me to try and come by and take a look. I am pretty familiar with this type of wiring.

[steveh]

Sean, I just checked the Hypotherm web page, at most you need a 60amp breaker.

Keep in mind, the Plasma cutter will output more amps that the input required because of how it's designed.

Even a 50 amp set up on a receptacle would work.

I would call Hypotherm, and verify what they suggest, and you’re golden

From the web site:

Specifications
(where indicated)

Input voltages 200 – 600 V, 1- or 3-PH, 50/60 Hz, CSA
230 – 400 V, 3-PH, 50/60 Hz, CE
Input current
@ 12.0 kW 200/208/ 230/240 (Supply Voltage you need) /480 V, 1-PH: 70/70/ 60/58 (Size breaker you need) /31 A

[NnF]

SeanP,

Just to ask a question ...

Did you say the power for your shop is coming from the house or did you just comment that the house had a 100 Amp Circuit ?

Later,

[SeanP]

hey. So I called two different techs at Hypertherm and they each told me that the maximum arc amps at startup is 96 at the highest setting and that I should wire in 100AMP. Now, the unit is rated to sever 1.5" and cut 1.125". I will likely NEVER use that size capacity.

My house has 200 AMP service so I should be able to tap a 100 amp breaker (assuming they even make something that size for residential boxes). Yes, I will put a disconnect near the unit with a slo-blo fuse.

Thanks for the info.

SeanP

[jasonmt]

Originally Posted by SeanP

hey. So I called two different techs at Hypertherm and they each told me that the maximum arc amps at startup is 96 at the highest setting and that I should wire in 100AMP. Now, the unit is rated to sever 1.5" and cut 1.125". I will likely NEVER use that size capacity.

My house has 200 AMP service so I should be able to tap a 100 amp breaker (assuming they even make something that size for residential boxes). Yes, I will put a disconnect near the unit with a slo-blo fuse.

Thanks for the info.

SeanP

My Miller 3080 has nearly identical ratings to your 1250 and as I previously stated runs fine off of a 50A/240V/single phase service using 6-50P and 6-50R plugs and receptacles. Setup like this I have used it to cut 37 degree bevels on 18" Sch. 80 pipe (0.931" WT). I would save your money and try it off of a 50A plug before you spend the $$$ to wire in a larger service to the machine.

[SeanP]

Cool, thanks for the offer. I have a friend coming over in the AM to help out. Truth be told, I will probably never use the full capacity of this machine to do over 1". I just want the ability to if I get an order for something. I will likely move into an industrial space with 3 phase in a year if all goes well with the business launch. I mean WHEN all goes well. I am totally stoked to start this business

SeanP

Originally Posted by steveh

Sean. looks like the general consensus is to hardwire it to a safety disconnect. I concur. Devices that can draw that kind of current don't use receptacles.

It's not a difficult job to add the breaker and do the wiring most of the time. Sounds like your panel is close to where your gona set up the machine.

PM me if you want me to try and come by and take a look. I am pretty familiar with this type of wiring.