# 2 or 3 wire for 220



## springer (Jun 16, 2020)

Just moved and need to run a couple 220 lines for all my junk. In the past, I've always done 2 wire because I have all single phase machines. Here, I now have a 3 phase machine and just got my vfd in the mail. 

Question is, do I need to run 3 wire to the vfd? I've tried searching and anything to do with a vfd is talking about wiring from vfd to machine. I am leaning towards not needing 3 wire, but thought I'd ask someone of more know how than me. I'm electrically challenged. 

Second question, if I do run a 3 wire, can I install some 120 outlets off that same 30a breaker? I've found info saying I cant run more than 1 220 plug on a 30a, but I'm still kinda lost. I was planning to run some 120v outlets to the same area and if I could do it through the same run of wire, thatd save me a little headache and money. 

Thanks in advance.


----------



## tq60 (Jun 16, 2020)

2 wire PLUS GROUND?...



Sent from my SAMSUNG-SM-G930A using Tapatalk


----------



## DavidR8 (Jun 16, 2020)

I just finished a VFD install on my mill. 
The 220b feed is two wire plus a ground. 
Bringing a third wire to the 220v outlet does give you the ability to run a 110v circuit using the neutral and one of the hots. 
Caveat: I’m not an electrician but this is what I have done. 


Sent from my iPhone using Tapatalk


----------



## ttabbal (Jun 16, 2020)

For single/split phase 220, you need 3 wires. 2 hots and ground. If you have something that wants 120v as well, you include the 4th wire as neutral. One hot + neutral = 120v. 

For a VFD you don't need neutral. For running the 3 phase output to the equipment, you need 4 wires. 3 hot phases, and ground. 

You can run 220v 4 wire and include 120v outlets, technically. I'm not sure what the code says about that. I don't think they would care so long as everything in the chain is rated for the current. That's one thing that might trip you up. Normal 120v outlets are rated for 15A, though in most areas you can chain them with a 20A circuit. Feeding one with a 30A breaker and wire might be a problem. If there is a short, you can get 30A through the 120V outlet, which could be a fire hazard. To be safe, I would run a separate 120V 20A circuit. The fire isn't likely, but it's cheap insurance.


----------



## markba633csi (Jun 16, 2020)

Ttabbal pretty much nailed it, 120 volt outlets are supposed to be limited to 20 A so a 30 A breaker might be a code violation
-Mark


----------



## markba633csi (Jun 16, 2020)

My feeling is you can wire up your house any way you want, as long as you use good practices. Bending the rules is ok sometimes, as long as there isn't a shock or fire hazard.
This applies to old houses and remodels.  For a new construction you pretty much have to follow the code or the inspector will have a cow, unless you are doing owner/builder interior stuff without moving walls


----------



## Ulma Doctor (Jun 16, 2020)

hey @springer,
glad to hear you are moved! i hope it was easy

Q1: 
you'll need 2 hot 240 volt wires and a ground to power up the VFD, a neutral wire is not necessary - there is no place on the vfd to wire it to

Q2:
i would run the 240v single phase to a distribution box (load center), then split into 120v circuits from the load center
from the load center you can wire the outlets and machines


----------



## DavidR8 (Jun 16, 2020)

For clarity, my 220v circuits are 20a wired with 12 ga wire and my 110v receptacles are rated for 20a. 


Sent from my iPhone using Tapatalk


----------



## mksj (Jun 17, 2020)

To clarify, their is no neutral in the US for using a 220V VFD, but you will often see a "N" terminal on the VFD. Do not hook this up to neutral, wire per the directions. Breakers protect the wire, there is some variations on sizing specs. of breakers relative to the a multitude of NEC codes, etc. Although it is not common to bring a neutral wire to a machine which is 220VAC, you can do it and then breakout separate sub circuits at the machine enclosure using supplemental breakers or fuses. Just remember that all the wire up to the fuse/breaker should be rated for power in breaker size (in this case 30A). On both my mill and lathe I use 4 wire cable (L1, L2, N, G), these then connect to the power disconnect switch at the machine and then to breaker/fusing if used. VFD's do provide guidance's on VFD fusing/breakers for each model, in general a 30A breaker is sufficient for either a 2 or 3 Hp single phase 220VAC VFD.

Example below, supplemental dual pole15A breakers for power supplies, second dual pole15A breaker for sockets mounted at the lathe and for DRO, and fusing for the VFD. The lathe is setup for either single or 3 phase 230VAC, but currently it is powered off of single phase. Attached enclosure diagrams give some suggestions, you need to comply with all electrical codes.


----------



## matthewsx (Jun 17, 2020)

How much would it save you to run 12/2 vs 12/3?

$15?

Just run the 3 wire and be done with it. Money is in the labor, not the materials, make it easy for yourself or the next guy if it needs to be something different eventually.

John


----------



## projectnut (Jun 17, 2020)

In many areas codes are changing.  We had a remodeling project a couple years ago which included installing a new range.  The old receptacle was 12-2 wire with 2 hot and a neutral.  The new code required 12-3  with 2 hot, 1 neutral, and 1 ground.  Fortunately when the house was built the contractor included a 12-3 wire feed to the receptacle. 

When I added circuits in the shop to power 220V equipment I used the 12-3 wire feed.  The difference in cost was minimal.  In our area a 250 roll of 12-3 wire costs about $108.00 from Home Depot.  A roll of 12-2 wire is about $60.00.  For a little less than $50.00 you can be ahead of any code changes.


----------



## springer (Jun 17, 2020)

Ulma Doctor said:


> hey @springer,
> glad to hear you are moved! i hope it was easy
> 
> Q1:
> ...


Thanks Ulma, I don't know why it never crossed my mind to run a distribution box. That makes the most sense. Then I can run a few plugs to give me more options in the future. 

I might give you a call when I'm ready to wire up the motor and stuff on that mill. It's still in pieces right now tho. I got a little carried away after I took it apart to unload it. Turned into a full cleaning and restoration project instead of a simple take apart and put back together haha.


----------



## springer (Jun 17, 2020)

mksj said:


> To clarify, their is no neutral in the US for using a 220V VFD, but you will often see a "N" terminal on the VFD. Do not hook this up to neutral, wire per the directions. Breakers protect the wire, there is some variations on sizing specs. of breakers relative to the a multitude of NEC codes, etc. Although it is not common to bring a neutral wire to a machine which is 220VAC, you can do it and then breakout separate sub circuits at the machine enclosure using supplemental breakers or fuses. Just remember that all the wire up to the fuse/breaker should be rated for power in breaker size (in this case 30A). On both my mill and lathe I use 4 wire cable (L1, L2, N, G), these then connect to the power disconnect switch at the machine and then to breaker/fusing if used. VFD's do provide guidance's on VFD fusing/breakers for each model, in general a 30A breaker is sufficient for either a 2 or 3 Hp single phase 220VAC VFD.
> 
> Example below, supplemental dual pole15A breakers for power supplies, second dual pole15A breaker for sockets mounted at the lathe and for DRO, and fusing for the VFD. The lathe is setup for either single or 3 phase 230VAC, but currently it is powered off of single phase. Attached enclosure diagrams give some suggestions, you need to comply with all electrical codes.
> 
> View attachment 327877


Thanks for the info mark, I always look forward to reading your posts. I have a lot of your diagrams and advice saved for when I start wiring my vfd.


----------



## Ulma Doctor (Jun 17, 2020)

springer said:


> Thanks Ulma, I don't know why it never crossed my mind to run a distribution box. That makes the most sense. Then I can run a few plugs to give me more options in the future.
> 
> I might give you a call when I'm ready to wire up the motor and stuff on that mill. It's still in pieces right now tho. I got a little carried away after I took it apart to unload it. Turned into a full cleaning and restoration project instead of a simple take apart and put back together haha.


Cool brother, call me if i can help!


----------



## ThinWoodsman (Jun 17, 2020)

projectnut said:


> When I added circuits in the shop to power 220V equipment I used the 12-3 wire feed.



How far are you running the 12? I was looking at adding a 30-amp 220V line across the basement, and getting towards 50-60 feet with the drops and all, I was worried that 12 wouldn't cut it. Not an electrician, so I just go by the tables in the Ugly's guide.


----------



## HMiller (Jun 17, 2020)

I've been toying with the idea of a few 50 Amp outlets scattered around near where I might put machines in the future. Then if I want something I'll put a plug on a subpanel and add the breakers I need. A little more expensive now, but the plug makes it not subject to inspection or permits. Then if I get a mill or shaper it is quick to give it whatever power it wants. 

This of course requires 4 wire (3 plus ground), but it saves pulling new wire in closed walls.

If it is a bad idea for some reason let me know...


----------



## mksj (Jun 17, 2020)

Not an electrician, but for running 30A wire from your panel to a socket the minimum would be 10AWG copper. Lots of sources as to types of wire, fill ratio if in conduit, etc. If you are running a motor or VFD with higher peak draws there are formulas for up-sizing the breaker or changing the breaker trip rating curve. If one was to run 50A sockets, then all the wire and sockets would need to be rated at 50A unless you had additional breakers/fusing for the smaller wire/socket size. It is also dependent on the type of breaker that one can use for branch circuits vs. in a machine electrical cabinet.

Typically I run a sub-panel in my garage and breakout dedicated lines each on a separate breaker, and or a cluster of sockets with different ratings and each on their own breaker. It does not stop you from using the same line/breaker for additional sockets at different locations. A bit different with extension cords, but for 30A I use a minimum of 10AWG for extension cords, typically generator cords since I use 4 wire.





						What Size Wire for My Breaker Do I Need?
					

Whether your breaker is a 30 or 40 amp, wire size is crucial for performance. Here’s how to determine what size wire you need.




					www.totalhomesupply.com
				




My current house I have two 200A panels on either side of my garage. Below is one cluster of two 30A 240VAC 4 wire, one 20A 240VAC 3 wire, one 20A 120VAC GFI setup for machines, I have the same repeated on the other side of my garage except I have a 50A 3 wire socket instead of the two 30A. All on separate breakers, I also have a string of 20A 120VAC sockets around the garage and sockets on supplemental breakers at my mill and lathe since they are in the middle of the garage.


Previous house had a similar setup, with a 100A sub-panel on the other side and had various socket clusters on 3 walls. If you are using the sub-panel at 100A then you need 3-3-3-5AWG copper wire 75C via conduit with the adequate fill volume, I pulled separate stranded THHN 90C wires mine was in 1.5" electrical PVC conduit about 35' from my main panel. I am limited to the the temperature rating of the sub panel which was 75C. Gauge also depends on the material/type of wire and distance. General guidance on conduit fill volume, I always go a bit bigger than minimum to make pulling the wires easier.








						Elliott Electric Supply - Lower Cost, Quality Electrical Supplies, and Personal Service
					

Electrical Supplies Distributor. Elliott Electric Supply is your local electric supply house. We Deliver Lower Cost, Quality Products, and Personal Service



					www.elliottelectric.com
				











						Elliott Electric Supply - Lower Cost, Quality Electrical Supplies, and Personal Service
					

Electrical Supplies Distributor. Elliott Electric Supply is your local electric supply house. We Deliver Lower Cost, Quality Products, and Personal Service



					www.elliottelectric.com


----------

