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Andrew Close
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280 Posts
Discussion Starter #1
hi all.
i got the correct tablesaw today :thumbsup: and am now working on the electrical.
i already have a 240V outlet in the garage, but it doesn't have the correct female outlet. the outlet in the garage looks sorta like a Y with the two upper legs being hot and the lower leg being common. the plug on the tablesaw is similar to a typical three prong 'grounded' plug for 120V applications, but the two flat prongs are turned 90 degrees of what your standard plug would look like.

---- ----
....0

something like that if you can envision the outlet in ascii art excluding the dots on the bottom ;)

so i went to Menards and picked up a new box, cover and outlet for 240V. now i've got the power disconnected from the garage completely and i'm going to install the new outlet. however, my new outlet has three posts on it: hot, common, ground; whereas the older 240V outlet that i'm replacing has two hots and one common. so my question is, do i just combine the two hots on the hot terminal on the new outlet and then wire up the common and ground as normal? also, is the 10AWG wire i bought ok for wiring up a single 240V outlet replacing the existing wiring? the existing wiring is quite old (not plastic sheathed, maybe cloth and tar?) and looks to be heavier than the 10AWG i bought to rewire with. i don't believe i'd be able to attach the existing wire to the outlet terminals let alone combine the two hot leads...

thanks for your help
 

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I'm afraid it might be better to call an electrician and have him take care of it. If I was looking at it and had a tester in my hand I can figure it out but trying to do it blind is dangerous plus it could burn up the saw.

If you could post some pictures that would help. Pictures of the wiring in the wall and new receptacle.
 

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790 Posts
The questions you are asking indicate you probably need to seek an electrician.

Typically, a red and black wire are used for 220/240 to indicate "hot", and the white is the common, or neutral...green is always a ground. Now.....follow this thought....220/240 may or may not have brass screws for the "hot" leads.....they may all be the same color. How we get 220/240 is the use of 2 110/120 volt leads, and they are not "in phase" with each other...so never, never, never even think about "tying" the hot wires together....it could be detrimental to your safety, no kidding.

If your saw is wired for 220/240, then it must be wired accordingly.
 

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I'm going thru the same thing; apparently the codes have changed and 220 now had 4 wires, 2 hots, a neutral and a ground. My saw, compressor and shaper all have just 3 wires. I'm not brave enough to eliminate or gang the neutral and the ground.

Here's the new 220 receptacle that I'm trying to figure out how to get my 3 wire cord into:
 

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Andrew Close
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280 Posts
Discussion Starter #5 (Edited)
good call Dave, not sure why i didn't post picts the first time around. :blink:

here is my wall:
240V_1.1.jpg

Fusebox :eek: i know. but it works. i replaced the fusebox in the house with a circuit breaker a couple years ago. the fusebox in the garage is fed from 2 120V 40A circuits in the house.

here is a closeup of the garage fusebox:
240V_2.1.jpg

here are the two outlets side by side:
240V_3.1.jpg

and a detailed view of the old outlets guts:
240V_5.1.jpg

this is the saws plug and the new outlet:
240V_6.1.jpg

the tablesaw has a single phase motor with the following electrical specs: 3 HP, TEFC, 230V, 60 Hertz
 

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Andrew Close
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280 Posts
Discussion Starter #6
if i was just installing a standard grounded 120V outlet i'd have no problem as i've wired many of them. however, i've never done anything with 240V. the thing that really threw me was that the outlet i purchased to match my tablesaws plug (rated 240V) didn't have two hot connections on it.

here's the terminals of the new outlet:
240V_4.1.jpg

that is why i asked if i was supposed to combine the 2 hots :huh::no:
after reading a bit about 240V and its phasing, i realize that that isn't a good idea. :no:

my other question regarding the 10AWG wire for the run was prompted because the existing wiring for the previous 240V outlet was quite a bit heavier looking; however, the two hot wires were both multi-strand wire. 10AWG was the highest rated wiring i could get at Menards. i'd typically use 12AWG for outlets and 14AWG for general lighting, but those are both 120V applications...

here's a shot of the old wires:
240V_8.1.jpg

and just for good measure, here's a shot of the new saw :thumbsup::
240V_7.jpg

thanks for any help!
 

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I would still call an electrician. There is something about your setup I don't like. No longer than the wire needs to be to feed the receptacle I would replace with new.
 

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"Drill" Sergeant
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141 Posts
first of 12 ga wire is plenty big enough, in 240 v applications the amperage is halved (if your saw draws 20A on 120 it draws 10 on 240). In this application you will want to run 12 ga 2 wire romex to the outlet. both are hot there is no neutral in straight 240 applications. there are 3 wires hot, hot, neutral in 120/240 applications like a range, but not in straight 240 apps like a water heater. make sure you don't fuse them higher than the 15a breaker that feeds the garage. If you run into problems tripping the breaker or blowing fuses you will have to upgrade the feed into the garage. So just run a 12-2 romex to the outlet, black wire to brass, white wire to silver, and ground to green. then hook up the ground to the fuse box, and the black wire into one fuse and the white into another fuse fed from the OPPOSITE busbar (or both will be pulling from the same breaker in the house).
 

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"Drill" Sergeant
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141 Posts
On another note, I would replace that fuse panel with at least a 50A subpanel run from your main panel, especially if you are running all of that equipment off of it. that setup is pretty sketchy, and if it is fed from 15A breakers, make SURE you dont have any 20 A fuses in that thing, you can be creating a fire hazard there
 

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Curmudgeon in Training
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824 Posts
I'm not an electrician but I've wired a few houses and my shop and none of them have burned down yet - knock on wood!

Regarding wire gauge: 10 gauge is for 30 amp, 12 guage is for 20 amp - doesn't matter what voltage, whether 110 or 220. I don't know what the gauge is but those multi-strand wires look plenty heavy enough to carry 20 amps. Although, if the insulation on those old wires is crumbly it might be best to replace them - doesn't look like it's a very long run.

Your new plug/recepticle clearly states it's rated for 230 volt however, it only has three screws, of which one is green. If, indeed it really only has three screws, the two brass colored screws are for the hots, the green is for the neutral or ground (they both work basically, the same). You did good by reading about 240 and understand DON'T COMBINE THE TWO HOT WIRES!

It may not be as "extra" safe as a four wire setup with black, red, white, and a safety ground wire but it is still safe and will work fine.

That's my opinion - BUT YOU MAY WANT TO CONSULT WITH A PRO before actually taking my advice. I wouldn't want to be responsible for harm to you or your property.
 

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Curmudgeon in Training
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824 Posts
I think I'd listen to Lucas - sounds like he knows his stuff. Disregard my incoherent ramblings.
 

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Andrew Close
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280 Posts
Discussion Starter #12
thanks Lucas. 12AWG will save me ~$40 since i can return the three rolls of 10AWG i bought :thumbsup: i already have several different colored rolls of 12AWG.
this project was supposed to be an outlet replacement, i didn't really want to replace the whole box. but you're right, it is a sketchy setup. there was a lot of that in the basement when i refinished it. :furious: i ended up rewiring the whole basement. don't worry, i had it inspected ;)
 

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Lucas:

What would you recommend for my set-up?

I have 3 prong like the first pic on my saw (borrowed pic from above, too lazy to take my own :) )

And receptacle like the second pic.

Technically, is the third prong on the plug a neutral or a ground?

Thanks!!!
 

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Banned
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496 Posts
Take the $40 your saveing and put it towards a new breaker box, that fuse panel just looks plain nasty, and so does the wireing. Call an electrician.
 

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Ozark Hillbilly
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541 Posts
:blink: Looks to me like in picture #5 the outlet was made upside down...

That ought to tell you how much I know about electricity... (and no, I'm not blonde...)

To be safe and not risk your saw going up in smoke, much less your shop, and to keep your insurance rates down, I would call a licensed electrician... :thumbsup: Of course, Lucas does seem to have that knowledge... :yes:
 

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"Drill" Sergeant
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141 Posts
wormwood, the plug is a straight 220V plug, 2 hots and a ground. there is no neutral in straight 220V (like a Hot water heater) , you only need a neutral for 110/220 DUAL voltage applications, like a dryer or a range( use the 220V for heating elements and 110V for electronics, timers, etc) tat said, just replace the receptacle with a straight 220 one like aclose has there. When you hook it up just cap off the neutral wire with a wire nut and tuck it in the back of the box, hook the 2 hot wires and the ground up to the receptacle.
 

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IMHO this wire is alumminum it needs to be replaced

Having said that. I am not an electrician. I have done some electrical work experance and if you use 12 -2 with ground wire (copper please) and wire the black and white to each leg ( so you have 220 volts accross them) and the ground wire to the box and the receptical. You will be ok. Please use an electrician as you also may have to worrie about rotation.
 
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