For all intents and purposes, your compressor will run fine on 30A/10ga. If your wiring is already buried in the wall, go with the breaker sized for that gauge wiring!! If you are installing NEW, then go 40A / 8ga. *just because*!!
[/SIGPIC]Necessisity is the Mother of Invention, But If it Ain't Broke don't Fix It !!
Mine's also a 5hp 1ph motor rated at 24 amps. When I hook up my fluke inductive ammeter to one of the leads in the service panel the motor draws over 70 amps (inrush amps) at startup (tank nearly full). My run is about 30 ft. It is a dedicated circuit, while the 20 amp circuits in my one man shop are daisy chained for the sub 1 hp loads of most other machines (wired to 220 to run them cooler)
Long and short, I decided to use 10 gauge wire to handle the full load rating of 24 amps, and put in a 40 A breaker to avoid tripping, mentioned above as allowable on a dedicated motor circuit. BTW Every time a magnetic breaker overload trips it becomes fractionally less able to handle overloads without tripping again more and more often. There's no cost savings in frequently replacing a prematurely worn-out breaker - not to mention the potential fire safety issue.
Not challenging you Chris, since I am no where near educated about the subject, but can you give the NEC reference for the allowance?
I have a Clearvue on 10 gauge wire that sometimes trips the 30a breaker, but would want the code, chapter and verse before I go and change anything.
You can find a current copy of the NEC code book at most good-sized libraries across the US. In mine they wont let you borrow it but will allow photocopying of needed pages for your personal use. Also very helpful is Wiring Simplified" 41st edition (by Richter, Schwann, Hartwell), available at most Home Depot Stores in the Electrical Dept. W.S. will give you the Readers Digest information and refer you to the code in areas where more detail is required, such as the allowable number of wires in a raceway, rules for dedicated motor circuits, etc.
FYI the code is HUGE and in multiple lb. large bound book that can be lain flat for copying. I wouldn't recommend any layperson to attempt purchasing it. The library is your best option IMHO. There's an online version if you dont have library close by, but I find the printed version much easier to access and cross-reference.
Last edited by Derby Matthews; 03-30-2010 at 3:37 PM. Reason: typo
I would check the motor nameplate to see what it says rather than rely on what some guy in customer service says. It's not his shop that is going to burn down if the wiring overheats and catches fire. Wire the circuit with the gauge appropiate for the current draw of the motor. Wiring is not a place you want to take chances.