Member
"SawStop technical support stated that 12/3 wire is OK."
These guys err on the safe side, and so 12/3 is fine for any hobbyists if they say so. Have you ever run your saw, any saw, non stop for half an hour at a time? I doubt anyone including those who do woodworking for a living in a non-industrial setup would run any of their machines (saws, routers, etc). non-stop for hours at a time.
Simon
Contributor
As good as that company is with ergonomics and user friendly features, a larger box and knockouts seems like a no brainer. Not much cost and it sure makes life easier when you can use either size wire or connectors. I generally use 10 soow and 30 amp twist lock to have some uniformity around the shop and it is a pain to have to buy smaller wire or work in a small box. Dave
Contributor
Steve
10/3 SO cord has an outer diameter of .670.
12/3 SO cord has an outer diameter of .610.
10/3 PVC has an outer diameter of .550.
12/3 PVC has an outer diameter of .490
10/3, or 12/3 is your decision. Ampacity for 10awg is 30 amps. 12awg is 25 amps.
FLA for a 5HP motor is 28 amps.
10/3, or 12/3 SO cord, is limited to the amps spec'd if the cord is less than 50'.
"The first thing you need to know, will likely be the last thing you learn." (Unknown)
Contributor
Those of you who favor 10/3 might want to think about your logic, for a second.
All wire gets hot when current flows through it. Picking wire size is just a question of "how hot is too hot?".
To be SUPER SUPER conservative, it was decided that 10AWG was sufficient to carry a continuous 30A load, even when that wire runs through a hot, insulated attic in the middle of summer in Arizona. Even in that adverse situation, 10AWG is the right size to not get too hot.
Now: why does anyone think 10AWG is required in an intermittent duty application, in a shop (probably laying on a cold cement floor)?
Contributor
Dan
No arguments from me.
I'm in agreement with John Lanciani. #12awg would be fine for this application. If memory serves, John is also a licensed electrician, so I'm confident in his answers. The awg of the wire coming out of the plug, has little to do with the size of the wire required to feed the receptacle.
The OP however wants a solution to use #10. It's his house, and his shop, and #10 certainly wouldn't be the wrong choice. I am only trying to provide an answer to the solution he wants to use, not change his mind.
Both cables have the same curves for heat. It's length that makes the difference.
Both of the 5HP motors I have are on #10, simply because they are both on SOOW "extension cords" that are right at the 50' length. I could have used #12, but one is an air compressor, the other is commercial washing machine. The washing machine probably has an actual 5hp motor, the air compressor is probably about 4-4 1/4, not counting service factors, and the manufacturer just used a little "Madison Avenue Engineering" to make it a 5HP. Probably the same "engineering " used for most new "5HP" wood working machines. Additionally, my "extension cords" have been known to spend the winter outside powering up trough heaters, for horses, from time to time.
All of this info is readily available on the Southwire website for anyone to access. You don't need to be an engineer, nor a licensed electrician, to understand it. Engineers Toolbox is another valuable website resource, for all kinds of topics.
Last edited by Mike Cutler; 07-05-2018 at 2:00 PM.
"The first thing you need to know, will likely be the last thing you learn." (Unknown)
Contributor
Absolutely, Mike - and I think your idea of PVC cord is pretty slick, if one wanted to squeeze 10awg in that spot.
[OP]
Contributor
Before purchasing the ICS I contacted SawStop and they recommended a dedicated 30A circuit, which I did using 10 gauge wiring and a twist lock receptacle. Looking more closely at the internals of the saw, the cable between the contactor, main switch, motor and terminal box is SOOW 12/3. It originally looked like 10 gauge because of the thicker 600V outer covering. So in conclusion, it looks like the 12/3 SJOOW (20' in length) I'm using based on SawStops recommendation is OK. The 5hp motor data plate shows 19.7A. 19.7A x 1.25 = 24.625A The 12/3 SJOOW is rated for 25A. Is this what makes it OK?
In response to one of the earlier comments. The SawStop Industrial cabinet saws do not come with a power cord like their Professional models.
Contributor
Steve
What makes it okay is the length of the cord, that it is only 2 current carrying conductors, and that it highly doubtful you will exceed the temp rating of the cable/conductor.
If you were to need to run a very long extension cord, say 100', than you would have to go up a size. To account for the voltage drop, and ampacity loss, of a longer cable.
I know that you ran #10 aww to the 30 amp receptacle, per the NEC, but it's as John Lanciani pointed out,the gauge of wire for the device plugged into a wall receptacle may have very little to do with the gauge of wire going to the receptacle.
I personally think it's kind of crappy that machines do not come with power cords. I understand why they do not, because the manufacturer can't possibly forecast all of the different installations, but they should at least be outfitted with the minimum length, and gauge, cord so that if a person were to change it, they would know it had to be "upsized".
I feel it leaves the owner in a vulnerable position. Simply stating to have the power connected by a licensed electrician can open a person up to some very expensive wiring mods, if they don't know any better. To make your cord will probably cost $50-$60 dollars. To hardwire it per the NEC might easily cost you twenty times that amount. Both installations are correct, and neither is wrong.
12/3 SOOW is still a fairly good sized cable, diameter wise. I would make sure it will fit through the strain relief first.
Last edited by Mike Cutler; 07-05-2018 at 6:28 PM.
"The first thing you need to know, will likely be the last thing you learn." (Unknown)
Guest
The knock outs are never the ideal size unless it's on 480v. Then it's a hotdog in a hallway.Originally Posted by David Kumm
It's not the saw manufactures fault either. They don't make the control housings.
Some of the euro stuff is down right infuriating trying to shove wires into the cabinet. Or, they put them in a really stupid spot and it's a bear to put a strain relief on.
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