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#183339 01/05/09 01:26 PM
Joined: Jan 2009
Posts: 1
U
ucan Offline OP
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I'd appreciate some input. I have several carrier fan coils used in commercial applications. They were installed in 1992. They all have single phase 208 volt 1 hp motors and toggle type 2 pole double disconnect switches. However, the control is provided with a pneumatic/electric switch (the hvac controls all use air) which only switches one leg of the supply to the motor. This seems unsafe as the other leg stays energized.
The original drawings called for 120v motors with this control setup. somewhere along the line the fan coils ended up being 208v.
Would appreciate any comments.
thanks

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Joined: Jul 2004
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As long as you have a real disconnect it is OK to switch one leg in a "controller"
Quote
430.84 Need Not Open All Conductors.
The controller shall not be required to open all conductors to the motor.
Exception: Where the controller serves also as a disconnecting means, it shall open all ungrounded conductors to the motor as provided in 430.111.


Greg Fretwell

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