Grizzly cab saw wiring question

[Jason White]

220-volt wiring question for G1023 owners...

Does the saw require 3 or 4 wires?

Meaning -- do I need both a neutral and a ground (4 wires)? Or just regular 12/2 with ground cable (3 wires)?



Jason

[Steve Clardy]

Just 3 wires. 2 hot, 1 ground

[Chip Lindley]

DITTO! 12/2 w/ground !

[Jason White]

Great! Got the circuit all wired up this morning.

New saw's comin' on Monday. YEEEEEEEEHAAAAAAAAAA!!!!!!

JW

DITTO! 12/2 w/ground !

[Jim O'Dell]

Did you get a plug for the saw's wire while you were at it?? Jim.

[Jason White]

Interesting!

I'm replacing my contractor saw with a new cabinet saw, but just for fun I rewired the contractor saw for 220 just to see if I noticed any difference.

I know this will probably start another fist fight with the electrical engineers who frequent this forum, but I'll be damned if the saw doesn't come up to speed more quickly and "seem" more powerful!

For what it's worth.

JW

[Jason White]

Yep! Sure did.

Did you get a plug for the saw's wire while you were at it?? Jim.

[Tom Veatch]

...I know this will probably start another fist fight with the electrical engineers who frequent this forum, but I'll be damned if the saw doesn't come up to speed more quickly and "seem" more powerful!...

Didn't put on my boxing gloves, and I'm not an EE anyway, but the startup transient (and other near-stall conditions) is where you'll see a difference in those cases where there is a difference.

[Jason White]

I have no idea what you just said.

Didn't put on my boxing gloves, and I'm not an EE anyway, but the startup transient (and other near-stall conditions) is where you'll see a difference in those cases where there is a difference.

[Tom Veatch]

I have no idea what you just said.

The difference between operating on 240v vs 120 volts, where there is an apparent difference, will show up under high current (amperage) conditions. Those are typically during motor startup and under near-stall conditions.

Anytime the motor is running at less than full speed, it will draw higher current, more amps, than normal - maybe anywhere from 4 to 6 times as much. That happens during startup as it accelerates from 0 RPM to it's operating speed - usually around 3450 or 1725 RPM for a 60 cycle induction motor. That's what I mean by "start transient".

It also happens when the motor is loaded so heavily that it slows down to a speed significantly below operating speed. That's what I mean by "near-stall".

The higher than normal operating current causes more loss in the wiring leading to the motor. The higher the current, the greater the loss in the wiring. That leaving less electrical power to run the motor. The effect is exaggerated with 120v relative to 240v because a 120v motor draws twice the amperage that a 240v motor with the same HP would draw under the same conditions.

(I didn't put on my boxing glove since I have no intention of getting into a fight over it. I'm not an EE, since my degree was in AE, sort of a sub-specialty of the general ME field.)

[Jim O'Dell]

Yeah, what he said!!
Jason, I noticed the same thing with my Ridgid when I rewired it to 220. Comes up to speed quicker. I think that makes many think it has more power, but it really doesn't.

And Tom, doesn't the higher amperage that the motor draws on 110 only make a difference in that on 220 it is split across 2 hot wires instead of the 1 hot wire on 110? It actually pulls the same amps either way, but with 2 hot wires carrying the amperage, isn't there just less loss, so therefore it gets what it needs quicker? Kind of like filling a gallon jug with two water hoses instead of one? Jim.

[Tom Veatch]

...And Tom, doesn't the higher amperage that the motor draws on 110 only make a difference in that on 220 it is split across 2 hot wires instead of the 1 hot wire on 110? ...

No, not really, Jim.

You've got two wires going to the motor in both 120 and 240 service. The only physically significant difference is the voltage between the two wires, 120v in one case, and 240v in the other.

I'm may get in trouble with this, since I'm playing fast and loose with the term "phase" as applied to electrical service, but here goes. In 120v service the voltage in the hot wire is nominally 120v relative to ground and the neutral wire, AKA "grounded conductor", is connected to ground so it's voltage relative to ground is zero. Therefore the voltage between the two wires is 120v.

In 240v service, the voltage in each hot wire is also 120v relative to ground, but they are 180 degrees out of phase. So when one hot wire is +120v relative to ground, the other hot wire is -120v relative to ground. That makes the voltage difference between the two hot wires a total of 240v.

All the current that comes down the hot wire in the 120v case goes back through the neutral wire to ground. In the 240v case, all the current that comes down one hot wire goes back through the other hot wire. In other words, the same electrons that come to the motor through one wire, 120 or 240, goes back through the other wire.

In a very real sense, if you ignore the fact that the neutral wire in 120v service is grounded, both 240 and 120 circuits work identically. The only difference is that with 240, neither of the wires is grounded so they are both "hot".

So, the current to the motor, isn't "shared" or "split" between the two hot wires in 240, it's just that one of them takes the place of the neutral wire in a 120 circuit. So while current is flowing to the motor in one wire, 240 or 120, that same identical current flows away from the motor in the other wire. Of course, the flow direction reverses every 120th of a second (every 100th of a second in some countries) which is why they call it "Alternating Current".

[Chip Lindley]

I KNEW THAAAAT!! I'm a Believer!! My old 120V/15A Rockwell Model 10 Became a Different Animal on 240V/7.5A!

Disclaimer: Any 120V/15A machine on a dedicated 20A circuit with adequate sized wiring will operate efficiently! BUT, this is seldom the case on a 15A shared circuit.

[Robert Payne]

220-volt wiring question for G1023 owners...

Does the saw require 3 or 4 wires?

Meaning -- do I need both a neutral and a ground (4 wires)? Or just regular 12/2 with ground cable (3 wires)?

Jason

Jason,

G1023 saws come with a 3-wire cord attached that is 10 gauge. Grizzly recommends using a NEMA 6L-20 (3-wire twist lock; you can also use 5L-20) plug and receptacle set and because the saw can draw 18 amps, it should be on a 20 Amp circuit. I wired mine with 10-2 gauge wire from my panel.

[Jason White]

I thought about 10/2 just to give me some "growing room," but in the end, I'm cheap and wanted to save a bit of $$ on the Romex, so I opted for 12/2 and a 20 amp breaker (plus they didn't have 10/2 at the local hardware store).

Seems to work just fine. I don't imagine I'll be getting any larger machines for at least a few years.

Jason

Jason,

G1023 saws come with a 3-wire cord attached that is 10 gauge. Grizzly recommends using a NEMA 6L-20 (3-wire twist lock; you can also use 5L-20) plug and receptacle set and because the saw can draw 18 amps, it should be on a 20 Amp circuit. I wired mine with 10-2 gauge wire from my panel.