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Khalid Ahmed

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Question: What is the smallest size motor which requires overload heaters I have a 1/16 HP does it require a overload protection? Please refer to code section.
 
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jusme123

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part 3 motor and branch ckt overload protection (starts at sec. 430.32 08 code)
 
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jumper

jumper

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Khalid Ahmed said:
I could not find the article you referenced to, does the 1/16 hp sump pump motor require an overlod protection.
Click to expand...

I think this is what you are seeking. For such a small motor, I would think it would be integral to the pump.

430.32(B)

(B) One Horsepower or Less, Automatically Started.
Any motor of 1 hp or less that is started automatically shall
be protected against overload by one of the following
means.

(1) Separate Overload Device. By a separate overload
device following the requirements of 430.32(A)(1).
For a multispeed motor, each winding connection shall
be considered separately. Modification of this value shall be
permitted as provided in 430.32(C).

(2) Thermal Protector. A thermal protector integral with
the motor, approved for use with the motor that it protects on
the basis that it will prevent dangerous overheating of the
motor due to overload and failure to start. Where the motor
current-interrupting device is separate from the motor and its
control circuit is operated by a protective device integral with
the motor, it shall be arranged so that the opening of the
control circuit results in interruption of current to the motor.

(3) Integral with Motor. A protective device integral with
a motor that protects the motor against damage due to failure
to start shall be permitted (1) if the motor is part of an
approved assembly that does not subject the motor to overloads,
or (2) if the assembly is also equipped with other safety
controls (such as the safety combustion controls on a domestic
oil burner) that protect the motor against damage due to failure
to start. Where the assembly has safety controls that protect
the motor, it shall be so indicated on the nameplate of the
assembly where it will be visible after installation.

(4) Impedance-Protected. If the impedance of the motor
windings is sufficient to prevent overheating due to failure
to start, the motor shall be permitted to be protected as
specified in 430.32(D)(2)(a) for manually started motors if
the motor is part of an approved assembly in which the
motor will limit itself so that it will not be dangerously
overheated.
 
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