Overload location

[csimon1]

I am having a discussion with an electrican at our plant about where the NC contacts of a motor overload are located. I thought that it had to be located on the ungrounded side of the motor starter. But I can't seem to find a definite code article. My electrican believes that it can be located on the grounded side of the starter. Any help in finding the correct answer and code article to back it up would be gratefull. I did come up with three locations, 404.2B, 240.22, and 430.885. My electrican says these apply to the overload themself, not the contacts of the overload.

Thanks
Craig Simon

 

[templdl]

Re: Overload location

Get a copy of NFPA 79 Standard for Industrial Machinery. I have a copy of the 1997 edition. Their may be a more recent edition.
Take a look at Chapter 9 Control Circuits, 9.4 Connection of control devices, 9.4.1 All operating coils of electromechanical magnetic devices and indicating lamps (or transformer primary windings for indicating lamps) shall be directly connected to the same side of the control circuit. All control circuit contacts shall be connected between the coil and the other side of the control circuit.
There are also (6) exceptions regarding OLR contacts, multipole relay circuits, ground test switching, solinoid test switching, etc.

 

[csimon1]

Re: Overload location

Thanks, My electrican found it before I did. In the 2002 NFPA 79 it states that OLs can be located on the grounded side if they are in the same control panel as the device. The article is 8.3 in the 2002 edition.