Question on wiring the Powermax 85

[iou]

I have read the section in the manual regarding the electrical hook up of the power supply
and understand Hypertherm recommends using a disconnect switch and slow blow fuses.
However, I would like to install a plug on the power cord to be able to plug into two separately located wall receptacles in my shop.
I have single phase 100 amp 220 volt service in my building. What size breaker should I use to do this?

If you guys could share your set-ups that would be appreciated.

If this plan is totally not recommended please share that as well.

Thanks in advance for all your input.

Regards, Ian

[jimcolt]

The breaker size is dependant on the voltage that you have available to operate your Powermax85. It can operate on voltages from 200 volts to 600 volts, single or three phase. The current (amperage) draw is highest at the low voltages and lowest at the highest voltage.

Let me know what your input power is, and I'll show you where (in the manual) you can find the breaker and amperage sizing information.

Jim Colt

Originally Posted by iou I have read the section in the manual regarding the electrical hook up of the power supply and understand Hypertherm recommends using a disconnect switch and slow blow fuses. However, I would like to install a plug on the power cord to be able to plug into two separately located wall receptacles in my shop. I have single phase 100 amp 220 volt service in my building. What size breaker should I use to do this? If you guys could share your set-ups that would be appreciated. If this plan is totally not recommended please share that as well. Thanks in advance for all your input. Regards, Ian

[iou]

Thanks Jim, but you might have missed it. I have single phase 240 volt (checked with a DVM) 100 amp service in my building.

If you are referring to the table on page 2-8 it only mentions 100 amp slow blow fuses at 230-240v single phase.

I also understand that I will need to change out the power cord for a 3-wire 6ga cord.

Thanks for the help. Maybe I missed something or maybe I've got under-sized service for an over-sized machine.
I just jumped on this deal without fully understanding it requirements. The only thing I really paid attention to was the single phase 240 volt input.

You've been a ton of help, and I'd like to get this thing up and running and work towards my cnc table goal which I'm sure will pose more questions.

Thanks again,
Ian

[jimcolt]

Sorry Ian, I must have read your post too quickly...now I see that you have a voltage listed!

The information that is supplied in the manual is based on National Electrical Code rules. There are occasional local code requirements that supercede the NEC....so it most often is the best practice to consult with a local electrician for this kind of advice.

You can refer to the wire conductor sizes listed in section two of the manual which are based on length of the wiring to the outlet...obviously if the length of the wiring to your outlet is over a certain length...then the conductor sizes need to be larger. Most users of Powermax85's are running on 100 amp circuit breakers without any issues. Under the majority of cutting conditions the actual draw of the Powermax 85 will be less than 60 amps.....higher input current draw will only occurr when you are stretching the arc or cutting materials that are near or exceeding the maximum recommended thicknesses. Cutting thinner materials, even at full amperage output, will draw much lower current.

I have been running my Powermax85 on a 60 amp circuit for about 6 months.....and have cut up to 3/4" steel without any issues. I use a 50' SO type extension cord (#6 awg wire) and am using standard 50 amp welder plugs......(none of which meets code). If I did a lot of production cutting...or cutting thicker materials I would expect to trip the breaker.....and overheat my extension cord or plugs/receptacles.

Slow blow fuses are recommended as plasma systems tend to have a very high inrush current rating...when the arc fires the power supply draws a lot of power for a few miliseconds in order to establish and maintain the arc. If there are issues with even a 100 amp circuit breaker tripping....it would be recomended that it be replaced with a breaker with a high inrush rating. This specification is less of an issue with todays highly efficient inverter power supplies...and it is extremely rare to hear of an inrush current issue.

If you decide to use a disconnect switch box (either by choice or by local code requirements) often the disconnect boxes have fuse slots....and inrush current is why "slow blow" fuses are recommended.

Receptacles for 100 amp single phase connections are available....but not at the local Home Depot!

Best regards, Jim Colt

Originally Posted by iou I have read the section in the manual regarding the electrical hook up of the power supply and understand Hypertherm recommends using a disconnect switch and slow blow fuses. However, I would like to install a plug on the power cord to be able to plug into two separately located wall receptacles in my shop. I have single phase 100 amp 220 volt service in my building. What size breaker should I use to do this? If you guys could share your set-ups that would be appreciated. If this plan is totally not recommended please share that as well. Thanks in advance for all your input. Regards, Ian

[iou]

Thank you Jim for your quick and honest reply that answers all my questions.
This gives me a good place to start and sets up a trip to the local electrical supply/electrician for some more reassurance.
I can't wait to finally flip the switch.

Thanks again Jim for all your help.
Ian