Wiring for 220 - Ridgid TS and Rikon BS

the 4 prongs in your outlet is for 2xHOT + 1xNEAUTRAL + 1xGROUND

if the saws manual calls for a 3 prong plug for 220 than it is not grounding the saw in which case you could follow the saws manual and forgo the grounding pin in the plug.

you could either get the same 4 prong plug to match your existing outlet and just not utilize the 4th ground pin, OR, replace your existing outlet with a 3 prong outlet and use a 3 prong plug to match it.

if you’ll follow the wire going to your service panel you’ll see the 2 hots connected to 2 breakers (or 1 large breaker), the neutral connected with the rest of the neutrals (with the other circuits) and the ground connected with the other grounds. this might help you figure out which wire is which.

safety first!

-- ㊍ When in doubt - There is no doubt - Go the safer route.

Well, it appears to need to be grounded. Here’s what the manual says:

“Connect the power cord white and black leads, respectively, to the hot plug blade terminals. Connect the power cord green grounding wire to the plug ground prong terminal”.

In their diagram, there are only black, white and green wires coming out of the saw. Not sure where the neutral went in this story…

The band saw manual for the Rikon says it has to be grounded. It seems to me like it would be 3-prong as well, black/white/ground, although not giving much info…Anyone here has rewired that specific saw for 220?

-- David - Tucson, AZ

my bad… feels like monday :/

220 has 2 hots – no neutral (DOPE). so you only connect the 2 hots and the ground.

in your dryer plug there should be a 4th wire which I believe carries 110v on it which should be disconnected from the panel/outlet. best course of action is to replace the 4 prong outlet with a 3 prong, and disconnect the 4th extra wire (might be connected in your panel to a 2nd 110v breaker) – this way there is no confusion as to which is which in the long run.

sorry for the confusion.

-- ㊍ When in doubt - There is no doubt - Go the safer route.

OK, thanks, I’m surprised that it uses no neutral, but I’m not familiar with 220v in the US, but that makes sense. I will look into this.

I know this may not be up to code, but how about wiring 2 plugs on the same circuit, knowing that only one will ever be used at the same time? Both band saw and table saw would be connected there.

-- David - Tucson, AZ

Extra question: does the type of plug/socket matter? I see some with straight blades, some with 2 blades perpendicular to each other…rated for 250V etc…which one is the “right” one? I see Nema 6-20, 6-15P etc…

-- David - Tucson, AZ

You guys are smarter than I am. I’d call a licensed professional to clear things up.

-- Paul, Clinton, NC

I have all my 220v stuff equipped with 15 amp 3 prong plugs. Black to black-white to white-green to ground.
Bill

-- bill@magraphics.us

The way US power works there are two hots, a neutral and a ground. At the panel, ground and neutral are tied together. If you measure from hot to hot, you get 220. If you measure from either hot to ground, you get 110. So a 110 circuit is one hot and neutral, and 220 is two hots, no neutral. You always get the ground.

So 3 prongs is correct for your tools.

Yes, you can have two outlets on one circuit. Your breaker has to match the wire size you use, but you can string outlets on that circuit all you want.

You want a plug/socket rated for the voltage and current the tool takes. Other than that, it doesn’t matter a lot.
Look at http://en.wikipedia.org/wiki/NEMA_connector for info on NEMA numbering.
You probably want a NEMA 6 series, since you don’t need the 110 neutral connection the clothes dryer has. If you need 20 amps, you need the NEMA 6-20, otherwise you can use the 6-15. P is plug, R is receptacle. So, NEMA6-15P is a 3 wire, 220, 15 amp plug.

Thanks, all clear now!

This will really help as those tools won’t occupy the other 110v circuits.

The wire is marked 8-2 and the breaker is a double one where both sides are marked 40A and the handles are attached together. My cooking range is also wired to the garage subpanel on another 40A breaker.

-- David - Tucson, AZ

220VAC in the US is essentially 2 separate 110VAC circuits that are 180 degrees out of phase; the neutral connection is eliminated and the 2 hots are used – since they are out-of-phase the voltage is 2×110VAC.

Have a look at this page for connector types. The connector conventions are intended to prevent inadvertently plugging a device into an inappropriate circuit (wrong voltage and/or amperage). I recommend that you hire an electrician to replace the dryer receptacle with one that is appropriate, or do it yourself after figuring out what is correct.

Edit: Never mind, same as brtech

-- Greg D. -- the price of freedom is tolerance

Thanks for the information. Can’t afford to hire professionals for small DIY things and I’m handy enough for most things after I figure out what’s what. My 220V experience is from overseas though, where it’s just a standard, so no need to worry about that.

As an aside, I just realized that the breaker that was used for the dryer is marked “welder” on the panel door, so I guess that was its previous usage…

-- David - Tucson, AZ

A 220 V circuit always has a double breaker, so you interrupt both hots if something goes wrong. In fact, that’s usually the only reason for a double breaker. 8-2 wire is good for 40 amps. Your tools don’t need 40 amps.

Wait, 8-2? Are there two of them for 4 conductors? You need to get the two hots and the ground into your receptacles. Are you going to gang-mount the two receptacles or have two separate ones with wire between them?
I think if you have a 40 amp circuit, code says you need to use #8 wire between them even though each receptacle is rated 15 or 20 amps. Not sure about that. If so, might be better to put a smaller breaker in the panel, and then use 12-3 (for a 20 A breaker) or 10-3 for a 30 A breaker between the outlets.

There is only one 8-2 cable going into the receptacle. Both receptacles could be next to each other, that would be no problem. Mostly this is so I wouldn’t have to unplug one saw in order to connect the other one.

-- David - Tucson, AZ

Huh. Old wiring, no ground I’d bet.

For safety, you really need a ground. I’d consider replacing the 8-2 with a 10-3 and drop the breaker to 20 amps.

It doesn’t seem old. I can open it up and look for the ground. It seems to me that the 8-2 cable carries 2 main leads plus a smaller gauge ground in between, per what I’ve seen online.

-- David - Tucson, AZ