Need Help!- Powermax 1000 - do I really need to replace the power cord for single phase?

[MoparJon]

I just purchased a Powermax 1000 to use with my Torchmate table. It did not come with a plug on the power cord, I need to purchase one to match my receptacle. (I will be using 230v, single phase.) The owner's manual says that it comes with an 8 AWG, 4 wire power cord for 3 phase operation, and it says that if it is to be used with single phase, I am to replace the power cord with an 8 AWG, 3 wire. This unit does indeed have a 4 wire power cord (black, white, red, green).

According to the diagrams in the manual, for both 1 and 3 phase, the green is grounded to the chassis, the black and white go to L1 and L2 on the power switch. The only difference for 3 phase is that there is an extra red wire, which goes to L3 on the power switch.

Instead of purchasing a new power cord, since I need to install the plug anyway, can't I just wire up the black, white and green as usual and simply ignore the red wire? The wire gauge is the same, its wired up the same, there would just be an extra wire in the bundle which isn't connected to anything on either end. (I would probably disconnect the red wire at the power switch and cap it off inside the unit.)

I can't think of any reason why I shouldn't do it that way, but figured I would check here first just in case there is something I am overlooking.

Thanks!

[Al_The_Man]

Yes, it will be the same thing.
Although strictly speaking you should use Red & Black for 240 if using 4 conductor cable, Green for ground and leave the white disconnected at both ends.
It is just that on single phase, white normally signifies Neutral.
The book shows 3 wire cable, and in that case you don't have much choice not to use White.
Al.

[jimcolt]

The reasoning is: Sometmes an 8 awg 4 conductor power cord will not fit in a single phase plug that is designed for an 8 awg 3 conductor cord. If it fits ok in the strain relief...then just use the 3 wires....clip off the fourth and you will be fine!

Jim

[MoparJon]

Thanks very much for the replies, guys! Glad to hear I was thinking OK on that. Thanks also for the explanation, Jim - I was wondering why Hypertherm would recommend replacing a perfectly good (and expensive!) cable, it didn't seem to make any sense until you mentioned the strain relief.

I dropped by the local Home Depot and picked up a 50 amp plug that matches my shop's 230v receptacles; it had an adjustable strain relief, and at its largest setting, it fits the 4 conductor cable perfectly. I'm making some chages to my table which aren't done yet, so I haven't actually used the unit yet, but did plug it in and flip the switch just to make sure the indicators lit up, and everything seems ok there.

Thanks again!

[xjdubber]

Maybe Hypertherm has stock in cable companies?

LOL

[jimcolt]

No....Hypertherm is just suggesting that for a particular voltage and phase set-up....that the proper cord is used as suggested by electrical code requirements. In reality....bigger conductors rated for a higher voltage is better.......as long as it can fit into the proper receptacles and cord strain reliefs.

Jim

[millman52]

I'm surprised it didn't ask for #6 wire for single phase. Course I usually tend ot over wire a bit anyway especially if the cord has any length to it more than 10' or so.