Multiple outlets on 220

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  #1  
Old 04-11-13, 10:47 AM
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Multiple outlets on 220

I am working on plans for adding 220 outlets to my garage. I have a table saw, band saw and another tool that needs 220. If I know that they will never be powered on at the same time, can I install three outlets on the same circuit run? Like a standard run of 110 receptacles. It will be a 20 amp circuit.
 
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Old 04-11-13, 11:20 AM
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Welcome to the forums!

I am working on plans for adding 220** outlets to my garage... can I install three outlets on the same circuit run? Like a standard run of 110** receptacles.
Sure. If you overload the circuit, it'll heat up the wire and trip the breaker.

**Tech Note: You have a 240/120V service, so neither 220V nor 110V is available.
 
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Old 04-11-13, 12:17 PM
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This topic gets discussed frequently in some of the wood worker forums. While there is nothing code wise that prohibits multiple outlets on a 240 volt circuit there is often reference to NEC article 430. My understanding from reading various threads on this discussion is that the general consensus is that article 430 does not pertain to portable power tools that can be moved from location to location within a shop.
 
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Old 04-11-13, 01:51 PM
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My understanding from reading various threads on this discussion is that the general consensus is that article 430 does not pertain to portable power tools that can be moved from location to location within a shop.
Article 430 most assuredly DOES apply! This Article pertains to motors, motor branch circuits and motor controllers.

That stated, as long as the pertinent sub-sections of Article 430 are applied there is no problem with having multiple receptacles on a 240 volt branch circuit.
 
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Old 04-11-13, 04:07 PM
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Ok Furd , I certainly respect your interpretation of the code, but the argument goes how do you calculate the requirements under 430, if you are building a workshop and don't know the specific equipment, make, model numbers, etc. or decide to move equipment down the road, how could you possibly compute anything?

If you search there are a lot of threads on the various forums concerning article 430 with responses also from people who do this type work on a daily basis. . Here is one statement I took the liberty of excerpting as it states what I believe to be my point of confusion.
"Article 430 is excellent in its proper application - dedicated motor circuits. I have two such circuits in my shop and the equipment on each circuit is hardwired through disconnects. Trying to apply 430, or reference it, or enforce it, in relation to circuits in which equipment can be plugged and unplugged at will is an exercise in futility."

I'm not trying to be argumentative but if you are installing 240v circuits with multiple receptacles and the current draw on any intended piece of equipment doesn't exceed say 20 amps and you install all the proper components for a 240V 20A circuit, then wouldn't the result be as Nashkat1 stated in the first reply. If the circuit is overloaded then the breaker trips?
 
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Old 04-11-13, 06:41 PM
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My understanding from reading various threads on this discussion is that the general consensus is that article 430 does not pertain to portable power tools that can be moved from location to location within a shop.
While much of Article 430: Motors, Motor Circuits, and Controllers, is clearly written to safeguard workers in an industrial or factory environment, the code always applies when electricity is being installed and used. After all, many of those factories evolved from small workshops.

Here's one example of a sub-section of Article 430 that applies directly to a small woodworking shop, and to the question the OP asked:
ARTICLE 430
Motors, Motor Circuits, and Controllers

IX. Disconnecting Means

430.101 General.
Part IX is intended to require disconnecting
means capable of disconnecting motors and controllers
from the circuit.

430.109 Type. The disconnecting means shall be a type
specified in 430.109(A), unless otherwise permitted in
430.109(B) through (G), under the conditions specified.

(F) Cord-and-Plug-Connected Motors. For a cord-and-plug-
connected motor, a horsepower-rated attachment plug
and receptacle, flanged surface inlet and cord connector, or
attachment plug and cord connector having ratings no less
than the motor ratings shall be permitted to serve as the
disconnecting means. Horsepower-rated attachment plugs,
flanged surface inlets, receptacles, or cord connectors shall
not be required for cord-and-plug-connected appliances in
accordance with 422.33, room air conditioners in accordance
with 440.63, or portable motors rated 1⁄3 hp or less.
So yes, Article 430 applies and tools can be moved from location to location within a shop.
 
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Old 04-11-13, 06:57 PM
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Yes and no. Remember, Article 430 does not pertain ONLY to the branch circuits but also the motors and controllers. If you have, say, a two horsepower motor on a table saw then you need in addition to the 20 ampere branch circuit a motor overload device and controller. This could be a thermal overload protector built into the motor and a horsepower-rated snap switch or it could be a full-blown magnetic starter with low-voltage release.

In a nutshell, you must provide short circuit protection on the branch circuit, generally via the branch circuit overcurrent protective device (OCPD) which is going to be either a fuse or circuit breaker at the source of the circuit AND you must provide overload protection for the motor itself. Thirdly, you need a means of disconnecting the motor from the branch circuit. The overload device can be as I mentioned above and the disconnecting device can be the cord and plug.

So, as I stated originally, Article 430 does apply. The trick is in seeing how to apply it in a cost-effective manner for the particular installation. An installation with several 20 ampere, 240 volt receptacles to serve loads that have the requisite control and overload devices is definitely in accordance with Article 430.
 
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