ssu's and csy's

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Praedatus1

Praedatus1

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Portland, Oregon
hey guys, here in Wyoming they seem to require us to put ssu (single gang fuse holders) or csy's (gould versions that mount on a 4-square) for furnaces. Is this really code? They are so archaic its not funny. Plus, the screws on the back stick out farther than any of the rest of the unit, causing serious arcing issues with ground wires. I swear they have not updated the design for 50 years.
Tim
 
It's certainly not an NEC requirement. It may be an odd ball local code, or more than likely, a local tradition. In any event, your best bet is to contact the AHJ and ask for a list of any local amendments to the NEC to see where this requirement is coming from.

If you can't dig up an actual written code, then your AHJ's are enforcing a phantom code.

Regarding the arcing, just use a deeper box or put some tape over the terminals.
 
I assume this is motor driven then see 422.32 and Peter Agreed..... Is this one of those with the unit switch combined? which would meet the disconnect requirement.
 
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dcspector said:
I assume this is motor driven then see 422.32 and Peter Agreed..... Is this one of those with the unit switch combined? which would meet the disconnect requirement.
Click to expand...

If the furnace required fuse protection, then it would be required to use an SSU. However, I have never seen a furnace that had an MOCP less than 15 amps and that required fuse protection.
 
I will talk to the AHJ and see what he says. I hate those box units and putting tape over the terminals is NOT an acceptable fix for me. In Portland and in Virginia we just installed a motor rated switch or cord and plug connection. And sometimes we used breaker lock-offs, but I do not prefer these as I don't typically carry locks.
Thanks
Tim
 
Peter I guess I am lost on this one I was thinking about a gas fired furnace let's say typical residential with normally a handy box mount with a fuse and a unit switch. Am I on the same page?
 
dcspector said:
Peter I guess I am lost on this one I was thinking about a gas fired furnace let's say typical residential with normally a handy box mount with a fuse and a unit switch. Am I on the same page?
Click to expand...

Yeah, we use them all the time. AHJ says it's overkill but perhaps due to tradition they are still used.

SSU = Safety Shut-off Unit in our informal lexicon.
 
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