Pulling 110 off a 220 leg?

R

reprosser

New member
Has anyone pulled 110 off a 220 leg of the motor circuit to drive the 110 relay of their cyclone? (this assumes using 3 wire romex with a neutral for the motor run)

I have to pull in a 110 light circuit into my noise room, so I can drive the relay with it - but I was wondering if pulling 110 off the motor circuit would "unbalance" the motor or cause other issues.:confused:
 
I wouldn't do it myself even though it could be done -- the cost of the 10/3 wire is probably more that comparable 10/2 needed for the cyclone and a length of 14/2 for the light and a 15 Amp outlet for DC accessories like a remote contol and a bin sensor power supply. The 120V line could be extended off your lighting circuit for the shop so you do not leave the closet accessories energized when you are out of the shop.

My .02
 
I have been struggling with the light circuit feeding the noise room - just because I have two banks of lights in the shop. Depending on where I am working, I only need one bank of lights. I put the noise room in the farthest corner, so it is the most likely area that might have the light bank turned off. Mostly, I have both banks on.

I REALLY like the idea of de-energizing the closet when I am out of the shop, and I think the low possibility of having to turn on the other bank of lights to get the cyclone running is worth the minor inconvenience.
 
Assuming that your banks of light are down the right and left sides, why not just run the closet 120V line to the normally used bank of lights.
 
110v off 220v

110v off 220v

Reprosser wrote: Has anyone pulled 110 off a 220 leg of the motor circuit to drive the 110 relay of their cyclone? (this assumes using 3 wire romex with a neutral for the motor run)

Yes. I've done exactly that.

In my setup, I'm dealing with a very low ceiling, and have to mount my motor within the cavity between two floor joists. Worried about air flow around the motor and thus overheating, I've included a 110V "box" fan to cool the motor. (Photos show this more clearly - thick black wire is 220V "dryer dongle").

As my setup is in an area where a 110V source is not easily accessible, I've drawn both the fan and relay 110V power off the 220V motor supply.
 

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110V off 220V continued ...

110V off 220V continued ...

I'm assuming that your setup, like mine, is in a residential setting. Your house should be supplied with 220V Single phase. All the 110V circuits in your house are derived off a pairing of one leg of the 220V and the neutral (white wire) - ( Red to Black = 220V, Red to White = 110V, Black to White = 110V).

In my setup (previous post) one leg (red-white) powers the relay, and the other (black-white) powers the box fan.

Need to watch your breaker capacity. A 220V breaker will act like two joined 110V breakers. The cyclone motor draw plus the draw off either individual 110V leg will be added and if exceeded will trip your breaker. Kept happening to me during motor starting. If the cyclone motor started and got to speed, it would keep going; but sometimes (randomly) startup motor surge + 110V loads kept tripping my breaker. This was solved by increasing breaker capacity. As I already had a larger 220V breaker, this was far cheaper than running a dedicated 110V circuit.

Additionally, drawing 110V off the 220V cyclone supply is safer as one dedicated breaker serves the device. If a dedicated 110V supply is run, one MUST make sure that both the 220V and 110V sources are off during electrical servicing.
 
Thanks for the replies. This is a residential situation. I am familiar with the usual branch wiring requirements, but not much on the motor stuff. I will have to review my NEC regs.

For instance, I will be running 10ga romex - which would indicate a 30A breaker. Since this is a dedicated motor circuit, perhaps it is OK to use a higher amperage breaker to accommodate the inrush + load, but I am a little wary. (of course, I don't need the fan, and the relay should not add much)

I will have a 110 lighting circuit nearby to use, but I see the safety factor of one breaker controlling the system while servicing.

McRabbet: I could run the line to the further bank of lights, but I am using a commercial system that plugs together, so it would take some extra work and longer wire to connect. May still be the best option.

It is interesting to have some options to think about.
 
220v off 110V

220v off 110V

I've used 8ga, and moved to a 40A breaker. The dongle and 220V dryer plug I used are also rated@ 40A.
 
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