According to the NEC what size wire would I need to pull from the J-box to the overhead door motor. Its a 20 amp single phase circuit. There are number 12 wires pulled to the j-box. The FLA of the motor is 3 amp. I want to say there is something in the code that would allow a smaller gage wire as long as its under a certain length.
Wire size for overhead door motor.
- Thread starter JdoubleU
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Required over-current protection for conductors is primarily covered by Art 240. To use a conductor protected by a breaker higher than it's ampacity you would need to meet criteria in 240.4 or 240.21.
Off hand, unless you motor controller has over-current protection and you can apply one of the tap rules in 240.21, I don't know of an allowance.
I might add you may want to check your specification sheet as a lot of door openers with that size motor require a smaller over-current device in the supply.
Off hand, unless you motor controller has over-current protection and you can apply one of the tap rules in 240.21, I don't know of an allowance.
I might add you may want to check your specification sheet as a lot of door openers with that size motor require a smaller over-current device in the supply.
The internal wiring of fixtures and applicances is not wired to meet NEC "building wiring" specs. They are wired to meet the corresponding NRTL requirements. Often they are a wire type with a higher temp insulation and thus a higher ampacity The same will be true of the internal wiring of your door opener.
If they come with a factory installed cord, likewise it must meet listing specifications that takes into account enviornment such as feee air and duty cycles, cord insulations ratings, etc.
Your supply circuit, however, falls under NEC requirements.
John120/240
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- Olathe, Kansas
Light fixtures and appliances are hopefully listed by a NRTL. The listing agency test these products and determines if they are
suitable for the intended use. Electricians follow the NEC. Internal wiring of fixtures and appliances is outside of the scope of the NEC.
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