Initial 240v Wiring Question

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.
 
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.
 
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.
 
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
 
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.
 
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.
 
You must log in or register to reply here.
Back
Top