Toggle Switch In A 115V AC Motor Conduit Box 2

[curvyrace]

For many years, my company has installed on/off SPST toggle switches in the conduit box(peckerhead) of 115V motors up to 1 hp with no reported failures. A man in our shop says there is a code stating that 1 hp is the limit for this configuration. In the past, when we went above 1 hp, we have gone to a manual motor starter in a separate box. Does anyone know if there is such a code regarding the 1 hp limit for putting a toggle switch in the motor conduit box?

 

[jraef]

There are numerous rules (here in the US) specific to motors 1HP and under that likely make it that way. The most likely candidate (in my opinion) NEC Article 430.32B; 1HP and under allows the use of an internal thermal protector as the Overload Device wherein the device does NOT need to prevent re-starting of the motor when it resets. So if the integral thermal protector trips and you are using a maintained toggle switch, once it cools down the motor will re-startt automatically if nobody changed the position of that switch. If the motor were over 1HP, that toggle switch would need to act upon a contactor that would drop out if the motor overloads, requiring someone to manually reset it. A manual Motor Starter then provides that functionality, hence you having to change to that over 1HP.


"You measure the size of the accomplishment by the obstacles you had to overcome to reach your goals" -- Booker T. Washington

 

[curvyrace]

Thank you jraef. That's exactly what I needed!