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A/C disconnect

2326 Views 4 Replies 4 Participants Last post by  Toronto Sparky
Can anyone tell me what determines whether an ac disconnect needs to be fusilble. I have a small commercial job that has 3 sets of air conditioning. Inside units are 60 amps, outside are 50 amps. I want to use the inexpensive pull out disconnects. Not sure where to find in the code. Thanks for you help
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Generally, only if the dataplate on the equipment says "maximum fuse size" do you use a fused disconnect. Most will say "maximum fuse or breaker size", in which case you can use the pullout since your branch circuit already has a breaker at the head end, more than likely.

If you're running a heavy conductor and doing a tap to each piece of equipment, certainly you'd think about using a fused (or breakered) disconnect in that case, but there's some good reasons not to do a tap. With the way the LOTO rules are, you'd have to dump your entire feed to all that equipment that's tapped off the heavy conductor to check fuses or change fuses, so that everything in the disconnect is dead. Bad design for 2011. Probably okay in 1980.
 
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With the way the LOTO rules are, you'd have to dump your entire feed to all that equipment that's tapped off the heavy conductor to check fuses or change fuses, so that everything in the disconnect is dead. Bad design for 2011. Probably okay in 1980.

Never thought of that.
Then again I'm too old and stupid to shut stuff down.
Guess it's good thing I am no longer working in the trade.
 
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