Hey guys, over the weekend i picked up a used Unisaw (36-812) which has the motor wired to run on 220, but the previous owners had it hardwired to their shops wiring system so it has no plug on the end of the cord. My question for you guys is what kinda plug do i need to put on, i assume 3 prong because the wire coming from the saw only has 3 wires in it (black,white,green). And when i was at Ace today looking at plugs they had at least 2 different 30A plugs, one with an L shaped prong and one with a U shaped prong.
Which of these should i use, and does it make a difference? I currently don’t have a 30A 220V outlet in my shop (garage) but will be undertaking wiring one shortly as i’m relatively confident in my wiring ability (do 110 stuff all the time). I picked up a 30A breaker but wanted to wait to ask what kind of receptical i should put on the wall, and if it makes any difference if i just use your average run of the mill Dryer type outlet.
Also the guy at Ace wasn’t exactly helpful when i asked what guage of wire i should use to hookup the outlet, i usually use at least 12 guage when running 20A outlets and 14 for 15A outlets, so does the pattern continue, ie 10 guage for a 30A outlet?
Any help would be greatly appreciated, i can’t wait to get this saw humming along, its quite a quality jump from my old benchtop saw that i had mounted in a large table. I’ve already taken the saw apart and cleaned it, readjusted the 90 and 45 stops and checked the blade for parallel to the fence so all that’s left to do is hookup the juice.
Thanks.
JD
Replies
If you're putting in both the receptacle and the plug, the only thing that really matters is that they match. Me, I like twist-locks.
30 amps is 10 gauge (in copper).
For what it is worth, I agree, it doesn't matter so long as you are putting in the circut you can match the plug and recepticle. I did it with my Jet and used 10 ga. copper, but I wonder if you need 30 amps. You may want to check the Delta web site and determine the amperage required, I seem to recall that you only need 15 amps on the 3 hp. 220v circut, and if that is the case 12 ga. wire is much easier to work with, especially if you have a deticated circut.
hmm, perhaps i will look at that, i already have 2 dedicated 20 Amp breakers running to my garage and it'd sure be nice to just switch out a recepticle instead of having to run a whole new 30A circuit out there, off to check the manual again.
Edit:
hmm, looking at the manual yields this:
The circuit should not be less than #12 wire and should be protected with a 20 Amp time lag fuse.
So next question. If i were to use the 20 Amp circuit that i have running out to my garage now (which used to run old table saw and nothing else) do i have do to anything special to it to get 220 V instead of the 110V other than switching out the recepticle (currently a 20 Amp rated switch controlling a 20 Amp 110V outlet). I have found that 220 required 2 hot wires, so do i just wire the black and white to the hot end of the fuse in the box, and keep the copperwire as the "neutral", that shouldn't be overly difficult if that's all there is too it.
JD
Edited 7/22/2003 12:16:10 PM ET by JDorn
Edited 7/22/2003 12:29:06 PM ET by JDorn
Ok, if you just wish to switch this so it's dedicated for your saw. First make absolutely sure nothing else is wired on this circuit. If it is, and you switch to 220, you will fry it, let smoke out, or start a fire.
To do this, take out the 20Amp 110 breaker and replace it with a 20 amp 220 breaker. Connect the black and white wire in the panel box to this new breaker (first wrap some black tape around the end of the white wire to show it carrys power).
The ground (bare) wire is connected to the ground buss bar. It should already be connected here. This is a ground, NOT A NEUTRAL. There is no neutral needed in a 220 circuit. A neutral carries power, a ground does not, it is a safety device.
Then put a new outlet on the other end. Again tape the white wire to show it's hot. Us a special outlet and a special plug on the saw, so it's impossible to accidentally plug a 110 anything into it. There are many many 220 outlets out there. I too like twist-locks for this type of thing, just get something that matches and is rated for 20 amps. Whichever is cheapest if it were me.
Pretty simple, a quick trip to the store and 1/2 hour or less, and you should be up and running.
From what you say in this post you really don't know much about wiring. Please don't proceed without full knowledge ... and having a qualified person do this is probably a better choice.
But if you're going to proceed, you need to have a dedicated circuit here. If you'vce got a 20 amp, 110 volt, dedicated circuit in the garage, you can change it over to 220 volts. What you'd do is replace the circuit breaker to a double breaker, one that congtrols 2 hot wires. You need to make sure that the new breaker goes over the two lugs in the box that are from the two main power lines.
Hook up the black wire to one of the posts on the breaker, and (after putting black tape on the write wire to signify that it's hot) put the white wire on the other lug. In the receptacle, also wrap the white wire with black tape.
Hook up the black and white (black wrapped at this point) to the two posts of the receptacle, and hook up the bare wire to the green post of the receptacle.
John
john, i know this already. It's been mentioned before. I've wired alot of 110 stuff before i just didn't know what breaker size i needed for the saw (which was rectified by looking at the online manual), and since i'd never run a 220 before i didn't realize you needed 2 hots.
I will be running an additional circuit to my garage since my fuse box is on the right around the inside of the wall that my house shares with my garage. One quick hole and about 25 ft of wire and i'm set. I'll be damned if i'm gonna pay an electrician 300 bucks to come wire up a grand total of 6 wire holding screws and drill one hole in my wall. I am quite capable of that, i just needed a few pointers on 220. Its the first time i've acquired an additional "appliance" that required another 220 plug.
And according to Delta, a 20 amp circuit providing 220 V using 12 Guage wire is sufficient to run the 3 HP Unisaw, says so right in the manual, so that's what i'm going to go with, espeically since i have about 200 ft of 12 guage wire left over from when i wired all the other 20 Amp circuits that i put in the garage. In the end i'll have 2x 20 Amp 110 V circuits for tools, a 15 Amp 110 V circuit for all the lighting and garage door, and a completely separate 20 Amp 220 V circuit dedicated for TS only.
I've never understood why some people can be so afraid of wiring, yes if you stick a freaking screw driver into the fuse box with the main line on that might be a "really bad idea", but its far from rocket science. Provided you take the time to ask a few questions if you don't know 100% how to proceed (as my post illustrates). Its no more dangerous than using your big powertools without knowing what you are doing, and by our presence here the lack of a formal tooling education hasn't stopped most of us from using them, after doing the appropriate research into saftey :)
JD
JD
If the saw is only 3 hp. a 20 amp circuit will work fine.
You only need the standard 3 wires to hook it up.
While some will tell you to put in the 4 wires (red, white, black, &
green) you only really need 3 wires.
The normal hook-up is red and black are hot and green is the ground.
You don't use the white.
So a #12 3 wire can be used by wiring it white and black hot and
green is ground.
Be sure to tape the white wire with red tape to mark it as hot.
As for the plug and outlet, a simple 220v 20 amp outlet with one of the hot connectors turned sideways is all you need. Just be sure they match.
Don't buy ACE, they use Eagle brand. Kind of poor quality.
Go to an electical supply and buy Leviton spec quality, much better.
Ask if you have more questions, or if I confused you by accident.
Jeff
thanks alot guys, i'm off to the store now to try and pickup some components.
and yes the saw is a 3 HP model, vintage 1994 i believe (also sold as 36-830 from what i've read today)
JD
Jeff, thx for the brand tip, got all Leviton plugs and recepticals from the Home Depot over the lunch hour.
Tonight i'll try get it all wired up.
Thx again for all the help guys.
JD
The power plug your looking for is an L6. It's a twist lock, 250v 20A. 12 gauge wire is ok but it would be better to use 10 gauge.
Enjoy,
Len
Jamie is "spot on". I also use twist locks. Make sure you get ones that are rated for the amperage of the circuit. I get mine at Home Depot, and I believe they're Bryant.
The black wire in your saw cord would go one of the "hot" lugs, the white wire in the saw cord to the other "hot" lug. The 30 amp breaker you got is a double breaker, for 220 power, right?
John
well i got a 20 amp double breaker for 220, I also got all the appropriate recepticals and plugs all rated for up to 250 V on a 20 A circuit.
Should be nice and quick since i don't have very far to go from my circuit box to get to the place i want to put the jack.
JD
For 3 hp, use a 30 amp duplex breaker. Wire with 10 guage. Code now requires four conductor: hot and hot (black and red), neutral (white), and ground (green). Your choice of 3 or 4 unless it's being inspected to the latest code.
I recently moved my dust collector outside into a shed added to the garage (shop - only my wife thinks of it as a "garage") and put in a 20 amp 220 circuit. The dust collector only had three wires so I put in a redundant ground after ensuring that the neutral was not connected to ground (with an ohmmeter).
If you do electrical work without a permit that has not been inspected and isn't up to code and your house burns, the insurance company may walk away. There's been several threads that have discussed this.
Thx for all the help yesterday guys, i installed the 20 Amp 220 circuit last night and all went according to plan, took me about 20 minutes and now the saw is purring along like a kitten.
JD
I think you're confusing a 240V tool installation with a 120/240V range and/or clothes dryer installation. NEC 250-60 allows the range/dryer frame to be bonded to the neutral for existing installations only, but requires a separate ground for new (as of the 1996 revision) installations, which means 4-wire (2 hots, neutral, ground). There is no NEC requirement for a neutral that isn't used in a strictly 240V application.
If a local code official insists on 4 conductor cable, I could only venture a guess that when they see a 30A receptacle, they want the 4-wire cable anticipating someone using it for a dryer. But then, the 3 hp Unisaw only needs a 20A circuit (it draws 12.4 FLA, and comes from the factory with a 15A plug and 14 gauge SO cord) anyway, so there wouldn't be a 30A receptacle tempting someone to plug in a dryer.
Be seeing you...
Edited 7/23/2003 10:32:04 AM ET by Tom Kanzler
Discussing this at work today, we came to the consensus that the redundant ground and neutral wire are required, just as you state, because someone may plug in a dryer (or other 220V household equipment). The neutral is needed because there are functions in a dryer that use 110 (one hot going to a neutral) and others that use 220 (one hot to the other hot at 180 deg phase shift). I couldn't figure out before why they'd require a neutral and a ground for 220, but your dryer statement hits it on the nose.
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