rooftop units

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The function of the disconnect is to allow the HVAC crew to safely work on or change out the equipment.

Here they normally don't even get permits to change out the units.

The job specs may call for them to be changed as in they are being paid for.
 
Which code cycle are you under? Is the disconnect fused or nonfused? The only thing I could think of you needing to change it out would be based upon an updated available fault current calculation condition at the unit, and if the fused/nonfused disconnect has a sufficient short circuit current rating at it; this could occur if the utility has upgraded to a larger transformer, or other site conditions that are only speculative at this point.

Are there specifications to change it as well? Heavy Duty versus General Duty and whether or not specifications call for a certain type.
 
rooftops

rooftops

tw1156 said:
Which code cycle are you under? Is the disconnect fused or nonfused? The only thing I could think of you needing to change it out would be based upon an updated available fault current calculation condition at the unit, and if the fused/nonfused disconnect has a sufficient short circuit current rating at it; this could occur if the utility has upgraded to a larger transformer, or other site conditions that are only speculative at this point.

Are there specifications to change it as well? Heavy Duty versus General Duty and whether or not specifications call for a certain type.
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The only reason we are questioning it is this is what the inspector wants.The disconnects are good with all proper labels on them.Never had to change out old disconnects if they are funcitional.They are 600 volt and not cheap.
 
mwl1952 said:
The only reason we are questioning it is this is what the inspector wants.The disconnects are good with all proper labels on them.Never had to change out old disconnects if they are funcitional.They are 600 volt and not cheap.
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There's no requirement to change it out with the caveat of my noted comments above, in addition to Growler's initial comment as well. Which code cycle are you under for your project?
 
No requirement to change them out. I only do if they are damaged in some way. I do several dozen a year, but rarely done with a permit. The inspected ones were all new installations anyway, so had new disco's.
 
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