220v Circuit Sizing
#1
01-02-03, 07:28 AM
220v Circuit Sizing
I am planning a circuit for my 220v tablesaw. I checked the spec and it draws 13amps at 220, making that a 20A minimum circuit. The new outlet is to be installed some 2ft from the panel (in the garage).
Assuming I use this outlet dedicated for the 13amp/220v tablesaw, should it be sized for 30A/10ga wiring anyway?
If I build an extension cord, should it also be 10ga (in a 10-2 plus Ground x 20ft)?
Thanks.
Assuming I use this outlet dedicated for the 13amp/220v tablesaw, should it be sized for 30A/10ga wiring anyway?
If I build an extension cord, should it also be 10ga (in a 10-2 plus Ground x 20ft)?
Thanks.
#3
01-02-03, 06:21 PM
Article 220-3(b)93) Motor Loads. Outlets for motor loads shall be computed in accordance with the requirements in Section 430-22 and 430-24 and Article 440.
It is not the same as lighting. Breakers provide short circuit protection, and can be sized larger than the wire size to allow for starting curent. The motor provides thermal overload protection and protects the wires form simple overload.
It is not the same as lighting. Breakers provide short circuit protection, and can be sized larger than the wire size to allow for starting curent. The motor provides thermal overload protection and protects the wires form simple overload.
#4
01-05-03, 09:51 AM
What about 430.42(C)? This eventually referes that "The rating of the attachment plug and receptacle shall determine the rating of the circuit to which the motor may be connected, as provided in Article 210".
So what is the configuration of the plug on the end of the cord?
So what is the configuration of the plug on the end of the cord?
#5
01-05-03, 05:20 PM
430-42 Is for "Motors on General-Purpose Branch Circuits". (c) further limits the circuit to a 15 amp load. If you install a 240 recep for the motor, it is not a general purpose circuit. Put in a motor circuit to avoid nuisance trips on start up.
#7
01-06-03, 09:09 AM
DaveB.inVa-
The motor circuits are very different animals. I have been doing them in industrial settings for years. When I did one for a 5 HP tablesaw the inspector freaked. There is very little industry where I am and he had never seen a motor circuit that was not a factory type (air handlers). I had to spend 30 minutes walking through the code and calculations with him. Lucky the block diagram at the start of 430 is there.
The motor circuits are very different animals. I have been doing them in industrial settings for years. When I did one for a 5 HP tablesaw the inspector freaked. There is very little industry where I am and he had never seen a motor circuit that was not a factory type (air handlers). I had to spend 30 minutes walking through the code and calculations with him. Lucky the block diagram at the start of 430 is there.
