When Do I Want a Neutral Available on a 220V Circuit?

Okay, Project New Shop is trundling along, and I'm in the spreadsheet-twiddling-and-wiring-permit-pulling phase.

Do machine tools ever do like some kitchen ranges and want a neutral so they can provide 110 to task lights, DROs, other bits and bobs, CNC stuff?

Or do those accessories always just get plugged into 110 outlets? Or if they are fed through the machine tool, are they compatible with 220 (or adaptable to either voltage).

I'm trying to figure out whether running a neutral is stupid because it's a waste of wire that will never, ever, ever (ever) be used, OR whether NOT running a neutral is stupid because it invokes Clause A, Section "You're Berked" of Murphy's Law and will immediately render 70' of wire behind drywall useless.

You could do a sub panel at the machine, and have a whole hoard of options for the future.

You need to give your 110 circuit its own breaker in a box on the machine if you bring a neutral with your 2 hots. You can't run a 110  circuit off a 220 breaker.

...well you can, but you shouldn't...

So, how does that work with my 220 range with lights and electronic controls?

In reply to jgrewe :

It wasn't my plan to break 110 out myself, but observing that some fully engineered devices take a neutral so that they have access to 110 made me wonder that's ever true of machine tools and their integrated ancillaries.

While I've read about "multiwire" arrangements that use 3-conductor 220 to feed 110 outlets, that's not something I'm doing and not the question here. This is strictly about whether one day I'll regret not having a neutral available in the run.

I ran a neutral to every 220v outlet in the shop, and haven't regretted it. It let me break out 110v with an additional breaker/box on the Bridgeport, as well as run the DRO. Mostly it's so cheap and easy to do now, why not?

A 240vac (not 220vac) machine tool like a table saw, etc. generally doesn't require a neutral wire, just the two hots and a ground.  A kitchen range does require a neutral wire.  However, it doesn't hurt anything to have the extra neutral wire in place, just put a wire nut on the unused wire and leave it disconnected in the junction box. 

VolvoHeretic said:

So, how does that work with my 220 range with lights and electronic controls?

Same as an electric dryer - it's a 4 wire plug

Paul_VR6 (Forum Supporter) said:

VolvoHeretic said:

So, how does that work with my 220 range with lights and electronic controls?

Same as an electric dryer - it's a 4 wire plug

Oooohhhhh...  so that's the difference between the 3-wire and 4-wire dryer plugs.  Well, I learned something today.

In reply to Tom Suddard :

Thanks, that's exactly what I was wondering!

I'd use conduit so you can pull what you need later.  Wiring for future, undefined, machine tools is such a gamble and the chances of having the correct gauge wire at the right voltage and phase are pretty slim if you don't have a specific machine in mind.  Here are the electrical panels for my shop.  The painted panel on the left is the main and feeds the house and the subpanel in the middle which is for all of the shop circuits.  The one on the top right is three phase 240 VAC. 

 My antique lathe (1913 or so F.E. Reed) plugs into the 220 VAC single phase outlet to the left of the main panel.  I've been looking at upgrading and I've looked at everything from manual machines to multi axis CNC.  They've had power requirements from 15 amp 120 VAC to 50 Amp 240 VAC three phase.  Since I'm shopping used and Murphy apparently lives in my shop I haven't looked at anything that can be feed by the current outlet.

Incidentally, most machine tools should be hard wired without plugs due to the safety hazards associated with breaking the connection to electric motors under heavy load.

In reply to APEowner :

Somebody really likes small bend elbows... pretty sure I see 18 of them in that one picture!

SV reX said:

In reply to APEowner :

Somebody really likes small bend elbows... pretty sure I see 18 of them in that one picture!

Prior to the pandemic I'd have carefully planed out that installation in CAD.  During the pandemic I was working 10 hour days at my computer in my home office and the last thing I wanted to do was spend more time there.  As a result a lot of my pandemic projects were planned on the fly and look a lot like this one. 

When I installed my Bend-Pak 2 post lift (XPR-10A), I ran a neutral in the conduit to it so I could have a 110v outlet for worklights, battery chargers, tools, etc.

Handy.

In reply to APEowner :

I get it. 
 

I never use CAD, but I'd have bent those conduits in a hotbox or heat gun to make the transitions smoother. No big deal- just poking fun. 

SV reX said:

In reply to APEowner :

I get it. 
 

I never use CAD, but I'd have bent those conduits in a hotbox or heat gun to make the transitions smoother. No big deal- just poking fun. 

That's because you know what you're doing and I don't!  I never thought of using a heat gun.  I'm going to try that.

stuart in mn said:

A 240vac (not 220vac) machine tool...

I assume you called out the different voltages for a specific reason. 
My initial AC instructions go back to the '70s, and at that time 220, 230 or 240 were three different ways to call out the two opposite hots of a neutral in single phase residential. Just like 110, 115 and 120 are different ways to call out the neutral to either hot. Any of the three is quite correct. 
Now 208, that's another animal. But very rairly an issue in residential. 

People will often say 110/220 or 115/230, but those are legacy values from long ago.  The standard residential voltage supplied by electric utilities in the United States for many years has been 120/240vac single phase.  Having said that, everyone knows what you mean when you say 220 or 230 so it's not a big deal - I'm just being pedantic since I'm an electrical engineer.  

220, 221, whatever it takes. 

Teh E36 M3 said:

220, 221, whatever it takes. 

Nice one! (Telling our age!)

Although, I bet a lot of folks recognize the line, but not the movie reference. 

In reply to 03Panther :

Mr Mom

In reply to earlybroncoguy1 :

Sure. But I bet there are a lot of folks that have heard the line, but don't know the movie reference. 
I sure many do know the movie; at least from re-runs.