# Initial 240v Wiring Question



## Navy Chief (Apr 15, 2015)

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!


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## JimDawson (Apr 15, 2015)

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


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## pdentrem (Apr 15, 2015)

It is what I did.
Pierre


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## Tony Wells (Apr 15, 2015)

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.


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## Navy Chief (Apr 15, 2015)

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


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## UncleRuss (Apr 15, 2015)

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.


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## Navy Chief (Apr 15, 2015)

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


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## mksj (Apr 15, 2015)

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.


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## gr8legs (Apr 15, 2015)

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


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## Wireaddict (Apr 16, 2015)

mksj said:


> 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.]


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## coolidge (Apr 16, 2015)

I have a 3 car garage shop with my tractor taking up one whole bay. So with limited space all my machines are mobile so I can push them up against a wall out of the way when not in use. So I installed my machine and welder outlets near my service panel and use flex cords.

1. 240 vac 30 amp 3 wire twist lock
2. 240 vac 30 amp 4 wire twist lock
3. 240 vac 20 amp
4. 120 vac 20 amp

For example my mill with the flex cord and Footmaster casters is quite mobile.


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## mksj (Apr 16, 2015)

NEC currently requires all 15 and 20 amp, 120 volt, single phase receptacles located in residential garages and unfinished basements to have GFCI Protection, this may vary by local code. I use industrial 20A GFI type receptacles and have not had any issues, they also have GFI breakers, but quite expensive. Often issues with GFI's tripping is due to improper or old wiring, or VFD install issues/improper grounding/shielding. Most machines run off 240V, so 120V circuit is for hand tools or portable type electric tools. If you use them outside, I prefer to have mine on a GFI. That being said, you can install what works for you. I use a similar plug setup as Coolidge, each socket on its own breaker.


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## Bill C. (Apr 16, 2015)

I agree with Stu, add larger or several conduits while putting in one.  Can always cap the spare ones.  My Dad used to install industrial conduit and pull 220 or 440 voltage cables at the GE plant in Louisville, Ky. Then he and gang he worked in would turn it over the electricians.


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## aliva (Apr 17, 2015)

I would  suggest you have a separate breaker for each machine, this way if you ever want to isolate one machine and work on it, you'll still have power to the others. Also run 240 volt 3 wire.
2 hot 1 neutral plus ground
. You don't have to use the ground but you will have the 120v capability. for accessories


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## Navy Chief (Apr 17, 2015)

At this point I am going to stick with a single run for the machines with a neutral included, there will be adequate current available on the circuit to run two machines concurrently if I need to (machines I am looking at are less than 10 amp max draw each), if I need to electrically isolate a machine I can simply unplug it. The additional cost to run 3 dedicated circuits combined with the additional labor is just not going to work out and I am not seeing much need for it in my shop.


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## Tony Wells (Apr 17, 2015)

In that case, may I suggest that wherever you pull off your 120 hot leg, you run it through a simple, surface mount fuse. I did this on a couple of my lathes inside the control box and punched a hole for a duplex outlet to provide power for the DRO. The fuse block is screw mounted to the back plane out of the way, and labelled as to purpose. Size the fuse according to its intended use.


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