I need help, just got my new unisaw yesterday, got it all assemebled, went to
plug it in, uh-oh. This thing has the weirdest plug i've ever seen. It looks
like a 120volt plug but the blades are horizontal. I have a 230v single phase
3hp unisaw. Checked motor to be sure. I have a 50amp 230v receptcle in my
garage. Do I just cut this wierd plug off and install a plug to match? Help
please! I can't wait to cut some wood!
IIRC, the plug that comes standard on the 3HP Delta Unisaws is a NEMA 6-15P.
Rated for 15amps, it will fit into a15 amp, 6-15R receptacle, as well as a
20 amp, 6-20R receptacle, should you decide to make a jumper or extension
I don't know that I'd cut the plug off and install another, but I guess you
could do that. I simply went down to Home Depot and picked up the correct wall
socket for the plug and mounted in the wall. Doug mentioned making a 2-foot
extension cord; that's not a bad idea either, but I think I'd make it a bit
longer; 6 feet maybe. That cord on the Unisaw always seems to be a few feet
It wouldn't be a bad idea to get a 20-30A breaker into the circuit. The
motor has overheat cutouts, but they won't protect from a short in the
junction box, switch, or plug. They also let the motor get a lot hotter
under stall conditions than would a reasonable sized breaker.
Ahhh! selective non-reading again.
For this case, I suggest making those short extension chords, as adapters,
so if you go to work somewhere that only has 220 at a dryer, you can still
Remember though, the equipment plugged into a 50 amp breaker will not be
protected at the right amperage. If you have a cord or switch short, it
will be a lot of juice flowing to trip the breaker.
The right way to do it is to put that smaller breaker in and the matching
receptacle. Or you could get a small breaker enclosure, rig a 50 amp plug
coming out of it, and a couple of 20 amp breakers with matching pigtails. I
don't know what an inspector would say, (I probably do) but it would
Jim in NC
I don't understand how you can fail to see my point.
Situation. You have gone to bed, and the switch on you fancy saw decides to
short out, when a mouse takes a leak on it. Your saw is still plugged in,
and the chord is laying in the sawdust in your shop.
Will the thermal protection in your saw, keep the shorted switch and the
saw's cord from getting so hot that it sets the sawdust on fire?
No, it won't. But the circuit breaker will trip, and protect not only the
saw cord, but the house wires also.
Now to complicate things one step further. Another situation.
You have a #16 wire cord powering a jigsaw, plugged into a 50 amp outlet.
(you made an adapter) The switch in the jigsaw shorts out, and soon the
current is flowing to the partial short at 49 1/2 amps.
What is happening to that #16 wire extension cord. I would guess it is
melted and glowing by now, but the breaker has not tripped yet. So now we
can see that the breaker needs to be of appropriate size to protect what is
plugged into it.
Jim in NC
I've got this 2 amp fan plugged into a circuit protected by a 20 amp breaker. I
guess I need to go down to the electrical supply store and get a 2 amp breaker.
We see your point. I don't mean to be rude, but "Once again, the purpose of a
circuit breaker in your home and shop electrical panel is to protect itself and
the circuit, ONLY!"
-Doug in Utah
I disagree. Can you tell? <g>
Are you up to date with the latest and greatest electrical codes? New
houses will have to have "arc fault interrupter breakers" for the bedrooms.
Know why? The present breakers being used were allowing too many house
fires, because the breakers were not tripping when your 2 amp fan shorted
out :-) Sounds to me like the inspectors sure thought the breakers should
be keeping the things plugged into it from becoming a fire hazard.
By the way, just because your fan only draws 2 amps, doesn't mean that it
isn't wired with heavy enough wire to protect it at a much higher amperage.
Jim in NC
If one is short on 240 volt power in the shop, this is a good answer.
Correct as far as NEC?? Probably not, but if done with reasonable
"correctness" it would be safe. By the way, I often see "extension panels"
on construction sites like this often.
You also could add a couple of 240 volt and a couple 20 volt breakers.
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