220V 1-phase elec for new shop

[Randall J Cox]

Mark, I just had an electrician upgrade my shop and larger sub-panel, already had 10 gauge to my two 240v outlets, he added two more outlets and we switched to 15, 30 and 40 amp breakers for nothing over 3 hp, based on his experience with startup draw. BTW, I worked in downtown Riyadh for 2.6 years for BDM at the Royal Saudi AF Hq (I'm ret USAF), so given your time and the "summers" over there, you really deserve a nice shop!!! Randy

[Thomas Bank]

4) No one has a 220V machine that needs the neutral?

I can assure you that nobody has a 220V machine that requires a neutral in the USA.

The only time you need a four-wire (2 hots, neutral, ground) setup for a combination 220V/110V piece of equipment - such as an electric dryer where the 110V runs the control circuits and powers the light while the 220V powers the heating element or an electric range where (again) the 220V powers the heating elements while the 110V powers the lights and controls.

By it’s very nature, 220V doesn’t need a neutral as it oscillates between the two hots. A neutral is only needed for a 110V setup as you only have one hot and need somewhere for it to “go” from there.

[Allan Speers]

I can assure you that nobody has a 220V machine that requires a neutral in the USA.

The only time you need a four-wire (2 hots, neutral, ground) setup for a combination 220V/110V piece of equipment - such as an electric dryer where the 110V runs the control circuits and powers the light while the 220V powers the heating element or an electric range where (again) the 220V powers the heating elements while the 110V powers the lights and controls.

By it’s very nature, 220V doesn’t need a neutral as it oscillates between the two hots. A neutral is only needed for a 110V setup as you only have one hot and need somewhere for it to “go” from there.

A clarification, please, since I am thinking of rewiring my shop:

One would still use a 4 wire main line, from the house service entrance to the shop sub box, correct? (even if the shop lighting was running off of regular house power.) - Or is it legal, when wiring up lights or a combi machine, to simply connect the local neutral to the sub box's mechanical ground? (using a 3-wire main line.)

[James Baker SD]

I also have a 5HP Oneida on 30A. I tend to start it with the blast gates closed, so it isn't trying to do a lot of work as it ramps up to speed.

[Thomas Bank]

A clarification, please, since I am thinking of rewiring my shop:

One would still use a 4 wire main line, from the house service entrance to the shop sub box, correct? (even if the shop lighting was running off of regular house power.) - Or is it legal, when wiring up lights or a combi machine, to simply connect the local neutral to the sub box's mechanical ground? (using a 3-wire main line.)

It would largely depend upon what codes your local AHJ (authority having jurisdiction) has adopted. It used to be that you could run a three-wire (hots and neutral) main to a sub-panel in a detached structure as long as there was no metallic path (water line, chain-link fence, or such) between the two structures. The 2008 NEC eliminated that possibility.

To further clarify, my original comment was relating to the question of 220V runs from a panel to receptacles within a structure. Running such a 3-wire 220V feed (2 hots and a ground) as opposed to 4-wire 220V/110V feeds (2 hots, neutral, and ground) is an entirely different situation than running between structures from a panel to a sub-panel (as you’re asking).

[David Kumm]

I would also second the notion to wire the shop externally. Might not look as pretty but machines, hobbies, and interests change- even within the same hobby. I started out with single phase small motor machines and then got into a project that demanded a big shaper. Now I have motors up to 12 hp three phase in the home shop. The ability to change wire or add a hot sure beats reinventing the wheel later. Dave

[mark mcfarlane]

My suggestion is to run 10 gage wire for all of the 240v circuits since that's the hardest piece to change later, even if it's in conduit. It would be "somewhat unusual" for you to need heavier wire for most woodworking equipment in the 1-5hp range. You can then adjust the breakers and receptacles over time. Something I did in my own shop is also to run the circuits out to a j-box before heading to an actual machine location. That makes it far easier to "relocate" a circuit termination over time, too.

Oh, and welcome back from the middle east!

Will 10 gauge terminate correctly (fit) in 20AMP 220V outlets?

[mark mcfarlane]

Here's my specs, so far, probably way more than anyone wants to read... Obvious a wiring diagram is in order.

Electrical - General
General notes

• All electrical work performed to NEC 2013 code
• No inaccessible in-wall wire splices.
• Copper wiring only
• Sub Panel
  
  • 24-slot 120-200? Amp sub-panel w/ separate external cutoff - (actually need 80 AMPs for tools, lights, + whatever the heater/AC requires.
  • Separate neutral and ground lines shall be run to the sub panel (not tied together at sub panel)

• Shop lighting (at least some interior lights and all exterior lights) would ideally be run off the current house system so they are not affected by the shut off

• All 220V wire runs shall be rated for 30 AMPs with #10 wire - even for 20 AMP circuits
• All 220V outlets shall be locking NEMA XXXX
• All 110V outlet circuits, outlets, and breakers shall be rated for 20AMPs with #12 wire

Shop Outlets

• Floor Outlets
  
  • 1-30 amp 220V for Combo machine, in floor
  • 1-20Amp 120V outlet in floor under workbench (roughly middle of ‘parking area’)

• All shop wall Outlets
  
  • Unless otherwise specified, the bottom of all outlets (120 & 220Volt) shall be 52” above ground level.
  • All 110V outlets around perimeter of room should be on alternating circuits, 4 circuits total
  
  
• Front and Back Wall Outlets
  
  • 20-Amp 120V and 20-Amp 220V Outlets every 6 feet along front (2 outlets) and back walls (3 outlets)

• Wall adjoining house
  
  • GFCI Outlet / Circuit by sink
  • 1-20 Amp 120V outlet & 1-20AMP 220V outlet on other side of door, along brick wall
  
  
• Wall Adjoining Garage
  
  • 3-20 Amp 120V and 3-20Amp 220V outlets along wall dividing garage

Machine Room Outlets

• 1-30 amp 220V dedicated for DC
• 1-20 amp 120V dedicated for compressor

Garage Area Outlets

• 2-20 Amp 120V outlets along each of the 3 full walls (6 outlets total, can be same circuit)

Outdoor 120V Outlets

• 1-20 Amp 120V outdoor outlet back corner of garage
• 1-20 Amp 120V outdoor outlet front corner of garage next to door
• 1-20 Amp 120V outdoor outlet near back yard door

Shop Lighting & ceiling outlets

• 4 switched circuits for lights, one for each of 3 rows, one is a three-way
• 3 T8 lights (every other fixture, down center) on a three-way switch w/ one switch by 36” door entrance from house, one switch by 36” door entrance from garage
• All T8 bulbs should be daylight bulbs
• Total overhead: Three rows of two-lamp T-8 fixtures, 6 fixtures per row.
• first rows are 4' from each long wall, with one row down the center (i.e. ~9' gap between rows)
• 1 ceiling fan middle of garage bay? Need to reconcile with air cleaner
• Ceiling Outlets
  
  • 2 ceiling outlets, one for each garage door opener, possibly next to door for lift master type openers.
  • 1-120V 20AMP switched outlet in SHOP ceiling, above garage bay and assembly table, for air cleaner.

[Dennis Yamamoto]

If you are going to use a power feeder with your combo machine, you will probably need an additional 220 volt, 20 amp circuit for the feeder. I have two 220 volt circuits running to my combo: 30 amp for the combo itself, and 20 amp for the feeder.

[mark mcfarlane]

If you are going to use a power feeder with your combo machine, you will probably need an additional 220 volt, 20 amp circuit for the feeder. I have two 220 volt circuits running to my combo: 30 amp for the combo itself, and 20 amp for the feeder.

Good catch, thanks Dennis

[Mike Heidrick]

I easily run a 5hp vfd, 5hp baldor reliance motor equipped shaper, and a 1hp comatic feeder on a 30amp circuit to my t1002s shaper. Also 1 circuit can powwer a mm20, .75 hp vfd, and a bandsaw feeder. But hey why not if you are starting new. Prob just easier in the future if you move you machine. Every spot in mine has at least two accessable tool only (no dc or compressor) 240v circuits. I did many many outlets/circuits though.

All my wiring is in wall but the sub panels are exterior so I can add conduit later if I ever need it but honestly I cant ever forsee why I will do that.

[Thomas Bank]

A few comments.

Here's my specs, so far, probably way more than anyone wants to read... Obvious a wiring diagram is in order. [Diagrams are always good. ]

Electrical - General
General notes

• All electrical work performed to NEC 2013 code
• No inaccessible in-wall wire splices. [That would be a code violation in any case.]
• Copper wiring only [The feed between main and sub-panel is typically aluminum - and not a problem.]
• Sub Panel
  
  • 24-slot 120-200? Amp sub-panel w/ separate external cutoff - (actually need 80 AMPs for tools, lights, + whatever the heater/AC requires. [I’d go with a 200A panel. It’s going to be less than $100 more and much less than any labor costs. Get a good panel. I typically spec Square D QO - don’t go for their Homeline panel.]
  • Separate neutral and ground lines shall be run to the sub panel (not tied together at sub panel)

• Shop lighting (at least some interior lights and all exterior lights) would ideally be run off the current house system so they are not affected by the shut off [Is this a detached structure or just a sub-panel in an attached structure? If detached, you won’t be able to run branch circuits from the primary structure.]

• All 220V wire runs shall be rated for 30 AMPs with #10 wire - even for 20 AMP circuits
• All 220V outlets shall be locking NEMA [NEMA L6-xx - where “xx” is amperage. EG: NEMA L6-20 = 20amp]
• All 110V outlet circuits, outlets, and breakers shall be rated for 20AMPs with #12 wire [A quality 110V receptacle will typically accept down to 10ga wire.]

Shop Outlets

• Floor Outlets
  
  • 1-30 amp 220V for Combo machine, in floor
  • 1-20Amp 120V outlet in floor under workbench (roughly middle of ‘parking area’)

• All shop wall Outlets
  
  • Unless otherwise specified, the bottom of all outlets (120 & 220Volt) shall be 52” above ground level. [Remember to place a few receptacles below workbench height for things that reside below the workbench. EG: A shop refrigerator, heat treat oven, etc.]
  • All 110V outlets around perimeter of room should be on alternating circuits, 4 circuits total
  
  
• Front and Back Wall Outlets
  
  • 20-Amp 120V and 20-Amp 220V Outlets every 6 feet along front (2 outlets) and back walls (3 outlets)

• Wall adjoining house [Ok, disregard earlier comment about detached structures.]
  
  • GFCI Outlet / Circuit by sink
  • 1-20 Amp 120V outlet & 1-20AMP 220V outlet on other side of door, along brick wall
  
  
• Wall Adjoining Garage
  
  • 3-20 Amp 120V and 3-20Amp 220V outlets along wall dividing garage

Machine Room Outlets

• 1-30 amp 220V dedicated for DC
• 1-20 amp 120V dedicated for compressor

Garage Area Outlets

• 2-20 Amp 120V outlets along each of the 3 full walls (6 outlets total, can be same circuit)

Outdoor 120V Outlets

• 1-20 Amp 120V outdoor outlet back corner of garage
• 1-20 Amp 120V outdoor outlet front corner of garage next to door
• 1-20 Amp 120V outdoor outlet near back yard door

Shop Lighting & ceiling outlets

• 4 switched circuits for lights, one for each of 3 rows, one is a three-way [Always a good idea. I have enough lighting to light things up like a ballpark, but can turn on limited lighting if I’m just out to grab a tool or such.]
• 3 T8 lights (every other fixture, down center) on a three-way switch w/ one switch by 36” door entrance from house, one switch by 36” door entrance from garage
• All T8 bulbs should be daylight bulbs
• Total overhead: Three rows of two-lamp T-8 fixtures, 6 fixtures per row.
• first rows are 4' from each long wall, with one row down the center (i.e. ~9' gap between rows)
• 1 ceiling fan middle of garage bay? Need to reconcile with air cleaner
• Ceiling Outlets
  
  • 2 ceiling outlets, one for each garage door opener, possibly next to door for lift master type openers.
  • 1-120V 20AMP switched outlet in SHOP ceiling, above garage bay and assembly table, for air cleaner.

[Jim Becker]

Will 10 gauge terminate correctly (fit) in 20AMP 220V outlets?

Yes...I do recommend oversize boxes for the 240v outlets and that helps with keeping things tidy. The 10 gage wire is, um...quite stiff. (even 12 gage benefits from the larger boxes)

BTW, I use twist locks for all my 240v circuits. Yes, they are more expensive, but I like the more positive connection

[Thomas Bank]

^^ Definitely. Calculate the cable fill you need and then go at least the next size up.

[Thomas Bank]

Also, add a couple of these in considering how much our phones, tablets, and such have become a part of every aspect of our lives.

http://ecatalog.hubbell-wiring.com/p.../WLFSB002A.pdf