multiple 230 volt outlets on one breaker?

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  #1  
Old 07-21-02, 03:23 PM
J
jeffgbook
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Question multiple 230 volt outlets on one breaker?

I've got a table saw and drill press that can be converted from 115 to 230. I only have two slots left on my panel and I was wanting to put two 230V outlets in series off of one double pole 240V 30A circuit breaker. Having lots of trouble finding help. Greatly appreciate any help. Thanks.

Drill press: 3/4 hp
115V / 230V
9A / 4.5A

Table saw:1-1/2 hp-2 hp (assuming this depends whether it's wired for 115 or 230)
115V / 230V
12.8A / 8.6A
Thanks again for any help.
 
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Old 07-21-02, 05:31 PM
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You've come to the right place, I think!
First question, does either piece of equipment have a nameplate or manufacturers instructions that indicate the maximum circuit breaker size permitted? For this size equipment, it is generally 20A max at 240V.
If that is the case, install a 20A - 2 pole circuit breaker and run 12/2 or 10/2 plus ground, depending on the length of the run, and terminate it in two voltage appropriate receptacles like NEMA 6-20R.
Your conductors would start at the panel (2 pole circuit breaker) and run to the first receptacle, then on to the second. Wiring of 240V is somewhat similar to 120V, except that colors are different, terminations at the panel, and receptacles are different orientation.

What type of plugs are on the equipment, you might need to change them for the correct blade orientation for fit into the receptacle.
 
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Old 07-21-02, 05:59 PM
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No no, don't change the plugs. If the plugs aren't the same, you're going to need two circuits. You can get two circuits by using skinny breakers.

As Ron says, tell us what the plugs look like, or what type of plugs the instructions tell you to use when you convert to 230 volts.
 
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Old 07-21-02, 06:27 PM
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Just out of curiosity,,, why change voltage?
 
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Old 07-21-02, 07:38 PM
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Thanks. I really appreciate the help HandyRon, John Nelson & sberry27. First: "does either piece of equipment have a nameplate or manufacturers instructions that indicate the maximum circuit breaker size permitted? For this size equipment, it is generally 20A max at 240V." I don't see anything about max circuit breaker size. I bought a 30A, but I bought the wrong brand anyway so I'll just get a 20A. I already have 10/2 wire plus ground ran to where I'm putting the recepticals. It's about 25 ft. of wire. The equipment has common 120V with ground plugs, but the manuf. instructions say to replace the plug with UL/CSA listed plug (is this o.k.?). Also how exactly do I connect the wires to the recepticals being in series. I thought I had it figured out, but got confused when I actually started trying to terminate the wires. sberry27: I'm really just doing it to see if I can. Plus it draws less current (for what that's worth). I was actually going to ask if all this trouble was worth it, but I'm too deep to quit now. Thanks a lot guys. I really appreciate it. jeffgbook.
 
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Old 07-21-02, 08:36 PM
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For those small tools its not worth the effort to change.
 
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Old 07-21-02, 08:42 PM
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Your table saw is 1 hp,,, no matter what the label says. I run that and anything under on 110 usually,, just for portability. For bigger things with hard starts,,, like bigger compressors 220 is good,,, or for long distance wiring or place with poor entrance service. Water well is one of those things I like to see 220.
 
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Old 07-22-02, 12:55 PM
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YOu have to look on the name plate of each motor and make sure it says thermally protected. Some single phase motors have a red reset button and some are auto reset internal thermal protection devices. If both motors are marked thermally protected then you may do as you wish.

Your 30 amp breaker is well within the maximums allowed for either motor found in 430.52 for branch circuit overcurrent device and 430.62 for feeder overcurrent device.

YOur receptacles would be wired daisy chain wiring style much like the general use receptacles are wired in a daisy chain style wiring.

You receptacles must be 30 amp 220 volt rated.

Your plugs on each motor must also be 30 amp rated and 220 volt rated.

Your motors must be internally converted to be 220 volt rated for you dual voltage motor. Check the back of the plate on each motor to tell you how to convert from 120 volt to 220 volt.

You receptacles will serve as your form of disconnect.

Your overload protection in each motor will protect the branch circuit conductor from over heating.

You conductor would be considered as a feeder and would meet the required 12.8 amp increased by 25% to 16 amps then your 9 amps added to that 16 amps would make your feeder size requirement to be 25 amp rated and that 10 awg wire would be rated at 30 amps well within the ampacity required.

Your 30 amp breaker in your panel would be the feeder overcurrent device again protecting the feeder conductor well within the maximum allowed.

Sounds like a plan to me as long as both motors say thermally protected on their name plate and unless someone catches something I am missing.

Look for a block on the name plate of your motor that says thermal and a "T" in the block beside that point on the name plate of each motor. This will confirm you have thermally protected motors which most single phase motors are thermally proteced that is allowed to be used as the overload requirement found in 430.32

Wg
 
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