220V 1-phase elec for new shop

[mark mcfarlane]

Trying to finish my shop design (at least get close) in the next week. Meeting with the builder to finalize the contract,... Shop is 27' * 30'. Subtracting doors, thats about 100' of wall space where tools may or may not end up parked.

Panel will be somewhere in the shop, so longest run will be about 40 feet.

I'll have a few 5HP machines and kind of know where those will be (4-way slider/combo, DC), but based on common wisdom, even if I plan where I think everything else goes, it will move.

So for starters,

1) what breakers do I need for 3HP and 5HP 220V single phase machines, without knowing what those machines are, or their startup current, or efficiency,...? 30 AMP for 3HP, 40 AMP for 5HP?

2) with #12 (30 AMP) and #10 wire (40 AMP), max distance of 40'?

3) Should I be running 3-wire plus ground to every 220V outlet (H, H, N, G)?

4) w/ NEMA 14-30R outlets for the 30 AMP and 14-50R for the 40AMP?

Cheers,

[Steven Wayne]

1. 5HP = 30A 10ga wire. 3HP = 20A 12ga wire.
2. In a building that small you don't need to worry about voltage drop.
3. For a 230V receptacles, two hots and a ground. Neutral is for 115v receptacles.
4. NEMA 14 is for 115/230v. You'll want NEMA 5 for your 115v and NEMA 6 for your 230v. I prefer twist lock so L6-20R, L6-20P, L6-30R, L6-30P and so on. You can get VERY good pricing on this stuff on eBay!

[roger wiegand]

5 hp is 3728 watts, or ~15.5 Amps at 240 v. In theory you should be OK with 12 ga on a 20 amp circuit. You need to find out the actual draw of the motor to be sure though-- the rules on motors are a lot more complicated than the simple math because of startup current and such. Unless the motor is under heavy load it won't draw that much most of the time, of course.

[Jim Finn]

When wiring a shop I suggest that you use EMT, (conduit) surface mounted to the walls. Much easier to change things in the future. Nothing is permanent.

[Steven Wayne]

I have four 5hp motors in my shop. They all list full load current above 20a. 12ga wire on a 20a circuit is undersized for any true 5hp motor.

[James Baker SD]

In 15 years, I have never tripped a 30A breaker feeding any of my 5HP machines, so I think 30A is big enough.

[John Lankers]

I have a 4hp bandsaw living happily on a 20 Amp breaker, a 7.5hp 3 phase saw/shaper with electronic inverter on a 30 Amp single phase breaker, a 4hp jointer/planer on 30Amp single phase and a 5hp cyclone dust collector that needs at least 40Amp to be happy. What I'm trying to say is - It depends on the start up current and how hard the motor is being used.
I won't get involved in a wire gauge discussion.
You can run a Neutral if you want, but it's only necessary if you're planning to pull 120Volt from that same circuit for certain controls or 'what have you' if I'm not mistaken.

[mark mcfarlane]

... What I'm trying to say is - It depends on the start up current and how hard the motor is being used....

...You need to find out the actual draw of the motor to be sure though-- the rules on motors are a lot more complicated than the simple math because of startup current and such. Unless the motor is under heavy load it won't draw that much most of the time, of course.

Therein lies the rub, since I don't know exactly what equipment is going into the shop.

It appears everyone is saying 30AMP is enough for a 5HP motor, except for a DC and maybe a large compressor which might need 40 amps on startup.

So it looks like:

1) 5HP = 30A 10ga wire, except for DC @ 40A w/ #8, and 3HP = 20A 12ga wire.
3) L6-20R & L6-30R & is there even a NEMA plug/receptacle for 40 AMPs? I see 30 & 50...
4) No one has a 220V machine that needs the neutral?

[Dennis Yamamoto]

My 5HP Baldor motor Oneida cyclone starts and runs fine on a 220 volt 30 amp/10 gauge circuit with a L6-30 plug and receptacle.

Therein lies the rub, since I don't know exactly what equipment is going into the shop.

It appears everyone is saying 30AMP is enough for a 5HP motor, except for a DC and maybe a large compressor which might need 40 amps on startup.

So it looks like:

1) 5HP = 30A 10ga wire, except for DC @ 40A w/ #8, and 3HP = 20A 12ga wire.
3) L6-20R & L6-30R & is there even a NEMA plug/receptacle for 40 AMPs? I see 30 & 50...
4) No one has a 220V machine that needs the neutral?

[mark mcfarlane]

My 5HP Baldor motor Oneida cyclone starts and runs fine on a 220 volt 30 amp/10 gauge circuit with a L6-30 plug and receptacle.

Thanks Dennis, and everyone else who has contributed so far.

[Robert Engel]

1. 5HP = 30A 10ga wire. 3HP = 20A 12ga wire.
2. In a building that small you don't need to worry about voltage drop.
3. For a 230V receptacles, two hots and a ground. Neutral is for 115v receptacles.
4. NEMA 14 is for 115/230v. You'll want NEMA 5 for your 115v and NEMA 6 for your 230v. I prefer twist lock so L6-20R, L6-20P, L6-30R, L6-30P and so on. You can get VERY good pricing on this stuff on eBay!

+1. I have all my 240 <3HP machines on one circuit no problems. Remember the breaker protects the wire, not the machine. I use standard 240 outlets and plugs. I've never had anything come unplugged. I don't think you need the expense of lock plugs unless they are overhead.

I agree with Jim re: surface mounted conduit. If you ever want to relocate or add a machine or circuit, it is quite handy.

Flexible metal conduit is another option I really like for a shop. You can buy it with the wire already inside (metal clad cable).

[Jerome Stanek]

My 5 HP compressor starts and runs fine on a 30 amp breaker

[Rich Riddle]

Most 30 Amp circuits will power a 5HP motor without complications. You can always get a slow start motor as well. Many tools have those. I am guessing you have similar power stations in Saudi Arabia since that is your indicated location.

[mark mcfarlane]

Most 30 Amp circuits will power a 5HP motor without complications. You can always get a slow start motor as well. Many tools have those. I am guessing you have similar power stations in Saudi Arabia since that is your indicated location.

FWIW, the new shop is in Texas. I'm retiring from Saudi after 15 years of 120+ F summers. Looking forward to an air conditioned shop.

The work will be done by an electrician, primarily to save some build time, I'm just spec'ing it out.

I understand the convenience and flexibility of external conduit, but for now I am trying to avoid it simply for aesthetics, but ...

[Jim Becker]

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!