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US 240V split phase supply cord
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pcplatypus:
We have an Australian 230V single phase piece of equipment that we want use in the US on 240V split phase (120 - N - 120).  What supply cord is used for 240V in the US and is this mandatory under the US National Electrical code?  I understand the US 240V colours are Hot L1 = Black, Hot L2 = Red, Neutral = White or Gray and Earth = Green/Yellow.  As Neutral is not used is a 4 core cable required or is a 3 core, Red, Black, Green/Yellow suitable?
jonpaul:
Hello, a few points:

1/ Regulation in USA is both NEC and local gov building electric .

Eg Los Angeles differs from NYC.

2/ Depending on the equipment KVA and portable/temporary/permanent the connectiond differ.

3/ See Mike Holt forum or Professional Electricians forum, may have an answer.

4/ Most USA AC, applicances washers, stove  e 240V 2 wire, and use Line..Line connect, NO neutral.

Thus a 3 pin connector L, L, Earth.

5/ See Hubbel NEMA plug for chart USA  r plug according   V, I.
https://image.regimage.org/hubbell-nema-plug-configuration-chart/

6/ Import of some devices may be prohibited if nont compliant toUSA EMI or safety regs.

7/ As safety, shock and fire hazards, Consult a lscenced electricina to install.

Good luck,

Jon
BrokenYugo:
How much current do you need and what sort of environment will it be in? I think there are about 6 or 7 different common ones off the top of my head between the 15/20 (NEMA 6-15/6-20) amp air conditioner outlets (looks similar to the usual 120V socket), 30 (14-30) and 50 amp (14-50) 4 wire with an extra neutral you can ignore, usually for stove/dryer, big RVs also use 14-50, the older 30 (10-30) and 50 amp (10-50) 3 wire stove/dryer with a shared neutral/earth (treat it like an earth wire for 240V load), and the 30 (6-30) and 50 amp (6-50) welder and big equipment socket. That's just what you usually see, if you look up a NEMA connector chart you will find more.

For a plain old 240V load a 3 wire cord will be fine, ignore the neutral, that's for 120V loads, convenience outlets on stoves and such.

Note some apartments will give you two phases of a 208 3 phase supply instead.

So yeah, it's complicated, you'll want to do some work ahead with your hosts to see what they can provide and adapt from there. Aside from welders most 240 stuff comes without a cord for good reason.

For lower power a 120-240 transformer is probably the easiest solution.
Stray Electron:

--- Quote from: jonpaul on February 29, 2024, 01:55:31 pm ---Hello, a few points:

1/ Regulation in USA is both NEC and local gov building electric .

Eg Los Angeles differs from NYC.

2/ Depending on the equipment KVA and portable/temporary/permanent the connectiond differ.

3/ See Mike Holt forum or Professional Electricians forum, may have an answer.

4/ Most USA AC, applicances washers, stove  e 240V 2 wire, and use Line..Line connect, NO neutral.

--- End quote ---

    Not true any more. Stoves etc used to use straight 220 VAC so they left out the neutral but many modern devices use the 110 VAC connection for control circuitry, timers, clocks, interior lights, etc so they require the neutral.  So all stove, washer and dryer cords and outlets are now 4 wire; L1, L2, N and Gnd.  To my knowledge all water heaters are hard wired in and still only use L1, L2 and Gnd but that will probably change if/when they start adding Smart Controllers or other electronic controls to them.

   Otherwise I completely agree with the rest of your post.
ejeffrey:
Nema 6-15 would be the  normal thing if you don't need neutral. It's somewhat common in industrial and commercial locations for moderately high power equipment -- espresso makers, computer racks, and vacuum pumps all often use this.  It's pretty rare in residential settings although it's used in wood shops for tools like table saws and dust collectors.

Excepting workshops, residential use is almost always either 120V or high enough power to use 30+ amp circuits such as electric stoves, clothes driers, and EV chargers.  But that's probably not what you want.

If your device is going to go in a commercial space there is a good chance the user will either have or be able to install a 6-15/6-20 outlet.  In that case it will receive 208 not 240.  But if you want more flexibility and don't really need the power it's much better to make it work off of 120.

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