Rikon 10-353 220V power supply

[Dave Mills]

I'm considering the Rikon 10-353 bandsaw, and noticed something interesting with the power setup. I'm curious actually if this is code compliant in the US.

The 220V power on the Rikon requires a 4 wire cord (2 hot, neutral, ground) and plug. Three of those wires go to the motor (2 hots+gd). The neutral, one of the hot wires, and the ground are also routed to the aux 110V power receptacle, for plugging in a lamp. That lamp is then of course on the same 220V circuit breaker in your house. Other bandsaw vendors all seem to say their aux receptacle just flat won't be powered if you're using a 220V motor.

This all seems rather nifty, but I'd swear that other times I wanted to set up such a way to share 220V and 110V on the same wiring, I was shot down because of electrical or code issues. But I'm not an electrician by any means, so maybe I just misunderstood. Any input here?

[Paul F Franklin]

I'm an electrical engineer by trade, not an electrician.

That said, I'm not aware of any code prohibition of this. It's fairly common for machinery to have 120 volt control circuits connected just this way. Electric stoves used to do this as well, although switching power supplies that easily operate off 240 make this mostly moot these days.

I think the more likely explanation for other saws not having 120 receptacles for lamps is that most of them don't have 4 conductor cords to bring the neutral to the saw. All my 240V tools came with 2 prong plus ground plugs.

[Dave Mills]

Thanks for the input, Paul.

I think the more likely explanation for other saws not having 120 receptacles for lamps is that most of them don't have 4 conductor cords to bring the neutral to the saw. All my 240V tools came with 2 prong plus ground plugs.

Yes, I'm sure that's true, though they're building the saws, and I presume at some point in time there was a meeting where "do we put in a 4-wire cord so we can supply the 110V receptacle?" came up. I wonder how many sales Rikon loses for this saw because of the 4-wire requirement. All my 240V tools are also on the same plugs as yours.

[Andrew Seemann]

NEC jurisdiction stops at the outlet. After that, it would be more of UL certification and product safety regulations and insurance/liability issues.

[Curt Harms]

I'm an electrical engineer by trade, not an electrician.

That said, I'm not aware of any code prohibition of this. It's fairly common for machinery to have 120 volt control circuits connected just this way. Electric stoves used to do this as well, although switching power supplies that easily operate off 240 make this mostly moot these days.

I think the more likely explanation for other saws not having 120 receptacles for lamps is that most of them don't have 4 conductor cords to bring the neutral to the saw. All my 240V tools came with 2 prong plus ground plugs.

So THAT'S how they do that. I have a Rikon 10-325 running on 240 volts. I added a 120 volt lamp and am just plugging it in to a separate 120 volt source. I was considering a 240 V -> 120 volt transformer for the light. If Rikon is indeed requiring a 4 conductor outlet they're not doing their sales any favors IMO.

[David L Morse]

...This all seems rather nifty, but I'd swear that other times I wanted to set up such a way to share 220V and 110V on the same wiring, I was shot down because of electrical or code issues. But I'm not an electrician by any means, so maybe I just misunderstood. Any input here?

Technically that's a "Multi Wire Branch Circuit". Google for lots of information. The NEC specifies requirements for them. Some reasons you might have met some resistance:

1) Many electricians just don't like them, for a variety of reasons.
2) While allowed by the NEC your local jurisdiction might discourage or even prohibit them.
3) You will need a GFI breaker that has a neutral connection and is rated for 120/240 V operation.

While I can't recommend modifying approved equipment there are some who would just cut the Neutral wire short and use a 240V plug, giving up the convenience outlet.

[Dave Mills]

Thanks for the info David. I will read up on the Multi Wire Branch Circuit.

Could you confirm:

3) You will need a GFI breaker that has a neutral connection and is rated for 120/240 V operation.

Are you saying that if I do buy this Rikon model, I need to do more than changing my outlet and providing the neutral wire (which I do have in the box and am comfortable enough doing), in that I also need to check and possibly replace my breaker?

[Jim Becker]

This is no different than with many appliances where 240v power is used for a motor or heating element but 120v power is used for other purposes. 120v requires the neutral. There's no issue with this accommodation being on the same breaker...it's intended to be that way. The single thing that's different here from most appliances is that you have the choice of what "thing" gets powered by the 120v utility outlet on the tool, but it's clearly intended for something like lighting, not powering some other tool.

[David L Morse]

....Are you saying that ... I need to do more than changing my outlet and providing the neutral wire (which I do have in the box and am comfortable enough doing), in that I also need to check and possibly replace my breaker?

Yes. Let's consider what you might find in your panel:

1) A standard 2 pole breaker (not GFI). In that case everything will work but you will have a general purpose 120V receptacle in your shop that is not ground fault protected. You can decide if that's an issue for you.

2) An older 2 pole GFI breaker that doesn't include a neutral connection. Your saw will operate but you won't be able to use the 120V receptacle because it will trip the ground fault protection.

3) A 2 pole GFI breaker that does include neutral. Be sure the neutral wire from your outlet box connects to the breaker and not to the panel's neutral bus.

So, no, it's not absolutely necessary to have the right breaker. You saw will certainly cut wood with any 2 pole breaker. It depends on what you want to do with the 120 V receptacle and if you prefer code compliance.

[Tom Levy]

I got the 10-353 scratch and dent for extremely cheap (550) and it was the first 220v tool I bought. I had the electrician put in the 4-prong twistlock socket required by the 353 and a second 220 circuit with the standard 3-prong socket for other uses. I didn't have anything 220 already, so it was easy to just specify what it needed for the install.

The utility socket has been quite useful, I have a small maglight plugged in permanently that lights the whole table. It's been a great saw.

[Dave Mills]

Great, thanks everyone for the info on this. I think I've got my arms around it.

[Lee Schierer]

Most modern electric ranges and dryers have dual voltage requirements and require 4 wires. The electronic controls require 120 while the heating elements need 240.

[Bill Dufour]

Older electric stoves and dryers used the ground as neutral for 120 volt lights etc. Now they are required to have a neutral wire if they use 120. I bet any 240 volt washing machine shad to carry a ground wire forever.
In the middle of a dry shop ground is not really an issue unless there is a metal water or gas line within reach.
Bill D

[Frank Pratt]

I've never understood why that was allowed under US code. No current over the bonding conductor has always been a sacred cow for as long as I've been electricianing (45 years)

[Jim Becker]

Frank, it wasn't so long ago where code and other standards were not reinforced quite like they are these days. I'm not surprised that certain appliances were designed the way they were.