Initial 240v Wiring Question

[Navy Chief]

I am in the process on having some 240V outlets installed into my shop space, plan is to run 3 outlets on a single 20 amp circuit so share between large machines, currently only a mill but a larger lathe and drill press will be added in the future. I am also going to have a single outlet 50 amp circuit installed for a welder. I am considering having the runs installed to include a neutral wire as opposed to just two hots and a ground so that I can have 120V available at any of the machines if I need it in the future, I know that I will need to replace the cords on the machines to have access to the new neutral but that should be an easy fix.

Are there any holes in the plan that I am not seeing before I start the install and regret something later?

Thanks!

 

[JimDawson]

Sounds like a good idea to me. Don't see a problem in your thinking.

 

[pdentrem]

It is what I did.
Pierre

 

[Tony Wells]

Common practice now on single phase 240 is to run a neutral and a ground in addition to the hots. Unless I am mistaken, some code situations require it. I see it on appliances such as dryers and electric ranges.

 

[Navy Chief]

Thanks for the replies, I was just wanting to make sure there was not something I had missed before I started running copper.

 

[UncleRuss]

As Tony mentions, the grounding conductor (GREEN) and the grounded conductor (WHITE) can no longer be the same wire. It was changed a couple code revisions or so back. I would say it would indeed be wise to run the wire on the initial installation. If you do not need it for the machine, just leave it coiled up in the box. No sense in buying cord/flex, receptacle, and cord end if you do not need it just because it is there.
Go get 'em Chief (7,8,9?) pile up the SWARF.
Former EM2, now retired electrician.

 

[Navy Chief]

Uncle Russ, thanks. I retired as an E-8, gotta watch them even numbered Chiefs....

 

[mksj]

Most machinery does not use a neutral, the reason for the code requirement in the Kitchen and Laundry room is because many of the controls systems run off 120V which requires a neutral wire. In addition to your 240V wiring, I would pull separate 120V wires (white/black) if you plan on having separate 120V outlet, and connect this to a separate 20A breaker. If you are going to breakout the 120V at the machine, then run a white to the outlet/machine. I use a 100A sub panel. I have separate wired runs (black, red, white, green) to my mill and lathe, neutral is needed because the DRO/lights are run off of 120V. Each machine has its own dual breaker sized accordingly. I run separate wires (white, black) for a 120V 20A outlet on a GFI. All wires are pulled through conduit. Code specifies the conduit fill ratio and wire sizing.

 

[gr8legs]

Conduit is cheap, labor is expensive. I'd significantly upsize the conduit (or add a duplicate, parallel run of empty pipe) to allow future additions without grief.

Stu

 

[Wireaddict]

Most machinery does not use a neutral, the reason for the code requirement in the Kitchen and Laundry room is because many of the controls systems run off 120V which requires a neutral wire. In addition to your 240V wiring, I would pull separate 120V wires (white/black) if you plan on having separate 120V outlet, and connect this to a separate 20A breaker. If you are going to breakout the 120V at the machine, then run a white to the outlet/machine. I use a 100A sub panel. I have separate wired runs (black, red, white, green) to my mill and lathe, neutral is needed because the DRO/lights are run off of 120V. Each machine has its own dual breaker sized accordingly. I run separate wires (white, black) for a 120V 20A outlet on a GFI. All wires are pulled through conduit. Code specifies the conduit fill ratio and wire sizing.

I agree but with a few comments. One reason it's good to run a dedicated 120V hot wire with the neutral for 120V accessories rather than using one of the 240V hot leads is that some 120V devices such as a coolant pump or exhaust fan could add enough current to the existing machine load on one of the 240V leads to cause the breaker to nuisance trip although the accessory load isn't enough to trip a 20A single pole breaker. Another comment is that the 120V GFCI breaker or receptacle may nuisance trip to the point that you'll replace it with a standard [non-GFCI] type. [I had a problem in my basement with a GFCI outlet that fed a clock & some lights tripping occasionally when my 240V well pump, which was on a different circuit, started. The only way I found to remedy it was to replace the GFCI outlet with a standard duplex type.]