My wife and kids have bought me a unisaw for my momentous birthday. I just realized that this will be the first landmark birthday of mine for which I have no hope of living to twice my age.
Anyway, I will have to wire my shop for 220. The first time in 34+ years that I have been forced to put 220 into my shop. My brother is a power engineer, so I will enlist him for the details to the breaker panel, but what type of plug should I use (if you can point me to photos, I would like to see them) and, while I am at it, what do you all recommend for the size of the breaker? I would like to get started before I am allowed to open the package.
Any other suggestions for someone in my position would be appreciated.
One answer is "buy whatever receptacle fits the plug that came on the saw". If I had to guess, I would guess it was a 6-15P, a picture of which can be found at
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This plug can be inserted into either of two receptacles; a 6-15R, or a 6-20R.
The difference between the two is that the 6-15R is designed to supply a maximum of 15A, while the 6-20R can supply 20A. A typical 6-15R installation would use #14 wire protected by a 15A circuit breaker (I'm assuming relatively short wire runs such as are likely to be found in a home shop). A 6-20R would typically use #12 wire and a 20A breaker.
I personally can see no reason to install the lower capacity circuit. The receptacles themselves cost the same, as do the breakers. The heavier wire is only nominally more expensive (pennies a foot). The labor to install either is identical. The saw will run just fine on either the 15A or 20A circuit, but since putting the 20A circuit in won't cost any more, there's no reason not to do it. Someday in the future, you might need the bigger circuit for something, and then you'll be kicking yourself for not having put it in.
A couple of caveats. First, there may be some code issues specific to your location that might preclude installing the 20A circuit. I can't think of what they might be, but anything is possible when government beaurocracies are involved. Second, I'm just assuming your saw came with a 6-15P attached. It's possible it came with a different plug, or even no plug at all (you get to attach your own, or hard-wire it). In that case, consult your electrician for advice.
The HP ratings of the motor will dictate the plug and recepticle, wire and curcuit breaker to use. If you don't plan on ever moving it you could just hard wire it in. Greg
Roy Smith wrote in news: snipped-for-privacy@reader1.panix.com:
This is way more information than I could determine when I bought my saw a couple of years ago. So I had my electrician wire for 30A.
The plug on the saw came in looking like 6-15P or 6-30P. I still don't know the difference, from the pictures. We made up the heaviest duty, locking plug extension cord we could from the components at the really good local hardware store. Makes it really easy to make sure power is OFF when I'm changing blades, or something else, down inside the saw.
While you're fussing around in the power panel, investigate whether it is feasible to put in a master tools circuits kill switch, for everything except the lights (and the freezer.) When I leave on a trip, I can now lock out the power to the big tools, and avoid trouble that way. Kids, even adult ones, sometimes have the funniest notion of what's OK in dad's shop, when I'm gone.
Thanks for the info guys. I was surprised to hear that there is a plug on the Unisaw. I kind of heard that all 220 volt equipment came without a plug. In fact (now that I think about it) I believe a friend of mine that got a Unisaw had some confusion as to what plug to get for his saw. Well, I guess I will find out when I open the thing.
I just checked my breaker box to see what I need to do to put in an extra
220v line. I have 28 of the 30 positions filled. Also, I will have to move one of the breakers over to the other side to put in a 220 volt breaker. Somehow I feel uncomfortable having every position filled, but it would seem like quite a job to put in another breaker panel. Also, is that code without doing something else. Maybe I should test my brother on this.
There are half-height breakers you can use to free up some space. Keep in mind, another panel doesn't mean more current to your house, just more breakers. Check your local code, the half heights should be ok. JOE
I don't see the wisdom of keeping a couple of spaces "open". The manufacturer sized the thing to handle "x" number of breakers. The odds that all the circuits will be at capacity at one time and taxing the panel seem low. If you've got something you want to plug in and you're holding back a couple of slots... seems like a waste. If you have something more you want a circuit for later, you have to add a panel or delete something you're using now. Meantime...
Actually I don't know that I have ever bought any 240 (my brother corrected me and that is the MODERN designation) volt equipment before. Seems like I saw a thread in the group in the past where it was implied that someone had purchased a 240 volt tool that came without a plug and there was a discussion on what type of plug to use. If you-all think that it comes with a plug, then I guess I should check what type it is (since there are several possibilities, I understand). My brother looked up what type of breaker I should use. He feels, since I am going to have a plug on the line, that the breaker on the line should be 35 amps. He said that if it was hard wired as a motor connection, the NEC rules consider that the thermal breaker in the motor is part of the overload safety system and the line can be 30 amps (as a minimum).
In talking to my brother, I find that I have only 150 amp service (the breaker in the panel is 150 amps). He was somewhat surprised. He has 200 amp service. He suggested and I am thinking that I might buy a subpanel. That would allow me to separate my lines a little more if I want to in the future.
I opened up the box enough to find that it does have a plug on about a 10 ft cord. The plug is a 15 amp plug (thanks Roy Smith for the URL to describe them). I went to Home Depot to get a sub-panel, breakers and wiring I will need. I will have a 20 amp breaker in the sub-panel coming from a 50 amp breaker in the main panel.
Hey, I looked at the blade that came on the Unisaw. Couldn't believe it. It is an OLD steel blade (not carbide tipped). I was very surprised. I think I would have just not put a blade on the Unisaw rather than to put on a blade that isn't as good as my standard blades of 30 years ago.
I suggest to you that a 10 foot cord might not be long enough, depending on where you locate the saw and if you have a movable base, etc. What I did was buy a 20 foot 12ga heavy duty extension cord at the Home Despot, cut off the 110 plug and socket, and hard wire one end into the beast and put a 220v 20a plug on the other. Buying the extension cord and the new plug is cheaper than buying the plain wire and plug.
Hi, Lowes has a "workshop panel" kit that makes it easy to add a subpanel for your shop. If you are down to your last 2 spots, you can use them up for your Unisaw, or use them to add a whole new panel. I added a subpanel a couple of months ago using this kit, and it was simple. The code enforcement guy checked it out (took all of 5 minutes), and gave it his blessing. Total cost about US$150, including subpanel, wire, conduit, and the permit. Lewis
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