how to install a switch for 220v 20a motor


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Old 01-28-02, 09:37 AM
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Question how do I install a switch for 220v 20a motor?

I need to install a switch for a 220v 20amp table saw. can i use a typical light switch or would I need a double pole single throw switch.?
 
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Old 01-28-02, 01:02 PM
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You cannot use a typical light switch. Why do you want to switch it, other than the normal unit mounted switch. Will it be running when the switch is used?
Sounds like you need a motor rated switch. I don't think it would be at a regular big box store.
 
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Old 01-28-02, 06:56 PM
Wgoodrich
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You will need a 240 volt rated double pole 20 amp rated switch. You can buy them that looks exactly like a normal light switch but it must be 20 amp rated and double pole rated for 240 volt. Shoud cost about 6 bucks or so. Be careful I haven't bought one for a few years price probably changed.

Wg
 
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Old 01-28-02, 08:20 PM
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Home Depot double pole switch is $6.90. It says it's rated for 120 volts, but I assume that means 120 volts on each pole. SKU: #615147. Leviton Model #RO1-CS220-2I. Available in white or ivory. Model R02-CS220-2W, SKU #589834, in white.
 
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Old 01-29-02, 07:48 AM
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Is the motor rated at 2 horsepower or less?
Depending on the full load amps of the motor, the regular snap switch needs to be 125% of the full load amps. See (2) below.

430.109(C) Stationary Motors of 2 Horsepower or Less. For stationary motors rated at 2 hp or less and 300 volts or less, the disconnecting means shall be permitted to be one of the devices specified in (1), (2), or (3):

(1) A general-use switch having an ampere rating not less than twice the full-load current rating of the motor

(2) On ac circuits, a general-use snap switch suitable only for use on ac (not general-use ac–dc snap switches) where the motor full-load current rating is not more than 80 percent of the ampere rating of the switch

(3) A listed manual motor controller having a horsepower rating not less than the rating of the motor and marked “Suitable as Motor Disconnect”
 
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Old 01-29-02, 09:14 AM
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There is no motor mounted switch. The table saw unit is 20 or 30 years old and a different motor was installed. I believe this motor was a compressor motor. It is rated at 15a 208Volts.

I need the switch to power it on and off.
Currently there is a very cheesy hook-up with a normal light switch and 12 gauge stranded cable without ground so i need to replace everyrhing from the motor out.
 
 

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