Length of Power Cord

[Randy Heinemann]

I am waiting delivery and setup of my PM 3520C lathe and decided that it would make sense to rearrange my shop and change the location of the lathe from where it is to a spot that would require a 12' - 15' cord instead of the 10' length I originally planned. My understanding of electrical and 220 V circuits is that a 15' 12-3 cord should not be a problem. The VFD Input Amp rating is 10A and VFD output to the 3PH motor is rated at 7.5A. Overall the circuit is a 20 A circuit.

Am I OK to use a 15' cord (might be able to get away with a 12' cord)?

[Bruce Volden]

That would be the direction I would go!

Bruce

[Ron Selzer]

Should be fine
I wouldn't worry until you got over 50', 100' would not be out of the question. Bigger issue would be now far from the panel is the receptacle and what wire is run to it. Total length of wire to panel is what counts (wire to receptacle plus cord length)
Example would be 100' cord plugged into a receptacle below panel is better than a 10' cord plugged into receptacle with 150' wire from panel. Learned that that one the hard way when I was young on a commercial job with wire in conduit. Finally traced wire back to panel over 200' to panel even though receptacle was less than 100' straight line to panel.
Ron

[Ronald Blue]

Something like this will work great. Put the plug you need on it. I use this same cable in the 10 gauge size for my 240 20 + amp machines. It's very flexible and durable.

https://www.menards.com/main/electri...4439081484.htm

[Bruce Lowekamp]

10A is not even vaguely an issue for a 12ga extension cord (as Ron said, until you’re at much longer lengths). I’d get something like 25’ so you can use it for other purposes/have flexibility in the future.

Bruce

[Randy Heinemann]

I already use the same 220V outlet for my 2HP Jet 8" HH Jointer. It's been fine for about 8 years. Also, when I had a warranty service issue on the joints, Jet asked that I check the voltage to the outlet and it was 240V and within their specs. I think the line to outlet from the panel should not be a problem.

[Mike Cutler]

You are well within the ampacity rating of that cord.
Cerrowire and Southwire have ampacity charts for all types of stranded wire cord if you need to reassure yourself.

[Randy Heinemann]

Thanks all. Always good to have verification when it comes to electrical things even if I think I have made correct decisions.

[Jim Becker]

My personal feeling is that cord length in the shop setting relative to safety is mostly about avoiding tripping hazards. As has been noted, length is generally not going to be an issue for things like voltage drop if one is using an appropriate gage cable. It's more about not having so much excess that if gets in the way as well as having enough length that you can pick the best and safest pathway.

[Dwayne Watt]

I already use the same 220V outlet for my 2HP Jet 8" HH Jointer. It's been fine for about 8 years. Also, when I had a warranty service issue on the joints, Jet asked that I check the voltage to the outlet and it was 240V and within their specs. I think the line to outlet from the panel should not be a problem.

Voltage at an outlet will be whatever your supplier has coming off the transformer. It is voltage drop due to resistance in the wire at a given current flow that eventually is the problem. The Jet folks simply wanted to verify that you were not running on some low voltage system. You likely could not measure that voltage safely under load on the jointer.

[Randy Heinemann]

That's a good point. The trick is to have a long enough cord to give flexibility on location (for those of us who don't have outlets everywhere; especially 220V) and not too long a cord so that it's in the way.

[Rod Sheridan]

14/3 would be fine, it’s rated at 18 amperes, no need for 12AWG....Rod

[Randy Heinemann]

I was surprised how inexpensive 12-3 cord was. After looking for the best price per foot, I found a roll of 12-3 cord at Lowe's for $22. Every other seller was more expensive up to $2 a foot.

[Jack Llewyllson]

My understanding of electrical and 220 V circuits is that a 15' 12-3 cord should not be a problem. The VFD Input Amp rating is 10A and VFD output to the 3PH motor is rated at 7.5A. Overall the circuit is a 20 A circuit.

Am I OK to use a 15' cord (might be able to get away with a 12' cord)?

A 20-amp outlet is usually supplied with 12-ga. NM through the wall. If that's the case, a 12-ga. extension cord isn't going to heat up, or induce resistance-based voltage drop, any more than the existing circuit does (unless your cord gets damaged).

Unlike when working with signal, mechanical connections for electrical supply usually don't cause significant issues. As long as your outlet is sound and your plug isn't bent or fouled, you may consider the extension cord literally an extension of the existing circuit. Another way to put it is that if a 12 AWG extension is going to cause you problems, you already have supply problems.

Because they're braided, however, extension cords can fray and break internally. You're also adding a connection if you go with extension cords, which is subject to partial disconnection. If it were me and I were fairly sure of the location, I would consider replacing the machine's supply cord with a longer, sturdier cord, because factories often "cheap out" on the cord, anyway. If you replace that skinny puppy with a stout, industrial cord of the length you require, you'll have a single connection. You'll also have peace of mind about the gauge, and less worry about it getting chewed up over time.

As Jim said above, however, your biggest concern here is simply avoiding tripping hazards. That's pretty easy with a lathe, since they often park up against a wall and you can just tuck the cord in along the baseboard.

Also, congrats on the cool lathe acquisition. I'm envious!

[Bill Dufour]

Too long a cord can be a trip hazard and a cord should never be coiled up nice and tight when in use, especially on a metal reel.
Bill D