Help Rockwell Unisaw 3 hp Single Phase Hookup

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Forum topic by DangerDoug posted 07-13-2017 09:57 AM 2196 views 0 times favorited 12 replies Add to Favorites Watch
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83 posts in 2094 days

07-13-2017 09:57 AM

Help I moved and need to rewire the shop.
The question is what is the minimum size wire and/or breaker I need for a 32 year old 3hp – single phase Rockwell Unisaw (I bought new).
Can I get by with 20amp and 12 gauge wire 225v hook up. The run from the panel is about 50’.

I noticed this house (built 2002) doesn’t seem to have the power the as the previous shop, where we had a transformer in the front yard.
Distribution panel at new location? Typical 200amp Cutler Hammer with plenty of room for new circuits.

Plz help and wish me luck!!


12 replies so far

View toolie's profile


2163 posts in 3075 days

#1 posted 07-13-2017 12:52 PM

Should be no problem at all.

-- there's a solution to every just have to be willing to find it.

View GR8HUNTER's profile


6318 posts in 1159 days

#2 posted 07-13-2017 01:44 PM

if I were you I would run a separate sub panel to the shop :<))

-- Tony---- Reinholds,Pa.------ REMEMBER TO ALWAYS HAVE FUN

View Carloz's profile


1147 posts in 1038 days

#3 posted 07-13-2017 03:07 PM

And then in a couple of years you will want a plasma cutter/welder/etc then what ? Redo the whole job ? Wire is cheap, running it expensive. So why limit yourself to 20A ?

View jonah's profile


2075 posts in 3745 days

#4 posted 07-13-2017 03:29 PM

A 60A subpanel would do the job nicely. The wire will be a lot more of a pain to run yourself (you’ll need 6ga I think), but it’ll be easier to run future circuits from a subpanel.

View DangerDoug's profile


83 posts in 2094 days

#5 posted 07-14-2017 07:54 AM

Thanks folks,
The 20amp run is probably not the best idea, but can use it for temporary power.
Sub panel, that’s a thought, but there’s 12 openings in the existing CH box, including the panel box outlet.
One thought was to run #10 around the shop for outlets at the 220 machines, all on one run/circuit.
Except the compressor, that would need to be dedicated.
I’ll need a dozen or more 120 outlets for the smaller tools and the vac system(s); could use 12/3, for quad/double outlets and use both sides of the panel for extra power.

*Vac system is a collection of Home Depot Shop Vacs. They sell a full size vacuums (12 gal) for $45 around the holidays; e.g. using two at the table saw, they work nicely and run quietly.

View hairy's profile


2885 posts in 3979 days

#6 posted 07-14-2017 11:58 AM

All 220 machines on 1 circuit is a bad idea, they need to be on a separate circuit.

It’s nice to have a lot of circuits, but how many tools will be running at 1 time? You may not need as many as you think.

In my basement shop I have one 220v circuit. My tablesaw, lathe and RAS are located so that they can share that 1 socket.

-- My reality check bounced...

View DangerDoug's profile


83 posts in 2094 days

#7 posted 07-15-2017 08:44 AM

Thanks Harry,

FYI guys, these are hard to find and expensive but fast/easy to install.
They can be installed using the 2 circuit option.

Hubble 4 Plex:
[can be found on Amazon]

View TheFridge's profile


10858 posts in 1933 days

#8 posted 07-15-2017 03:47 PM

If the FLA of the motor is 16.1 to 24, it should be on a 30A ckt.

-- Shooting down the walls of heartache. Bang bang. I am. The warrior.

View WhyMe's profile


1169 posts in 2008 days

#9 posted 07-15-2017 07:21 PM

Don’t know where you live, but here in Virginia general use multi-outlet circuits are limited to 20A. Anything 30A and up needs a dedicated circuit. If you do a multiwire branch circuit (MWBC) it needs to be on a double pole breaker or two single pole breakers with a handle tie. Personally I don’t suggest a MWBC because it creates problems because of the requirement of GFCI 120V outlets in a garage. You can use a double pole GFI breaker but they are expensive.

View DangerDoug's profile


83 posts in 2094 days

#10 posted 07-19-2017 08:53 AM

Thanks for the messages.
Honesty hand’t thought about GFI’s, and that probably is code (there’s already one in a receptacle box next to elec panel). Throwing in the towel though and calling an electrician, I know a fellow that just retired a couple months ago, he’ll get up up and running (as long as the cost is reasonable).

View DangerDoug's profile


83 posts in 2094 days

#11 posted 07-19-2017 09:29 AM

Here’s a question about mounting the boxes. The shop is in a 1,300sf basement, walls have typ hanging insulation and don’k think I want to build 2” x 3” walls all around. So what about mounting boxes right on the insulation, one or two bolts right into the concrete? (the insulation contractors don’t give this a second thought).
I could pipe between boxes for the wires, maybe at 52” high, the conduit will help push the insulation tight to the wall.

View DangerDoug's profile


83 posts in 2094 days

#12 posted 06-25-2018 08:41 AM

I did find out a few things, and the 12/2 extension cord did work ok—not that I was cutting 3” lumber on the Unisaw.
With only 7 – 8 “spares” left in the breaker panel my best bet was to double-up on the 220v machines, and replace machine(s) 6’ power cords with much longer power leads and get 2 for 1 per slot (in the power panel).
This is pretty easy do with heavy-duty receptacles:

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