Motor control circuits

[caveman7]

Motor control circuits

According to the N.E.C. can you run a 24 volt control circuit in the same raceway with a 120 volt motor circuit if the motor controller has a control transformer in the same motor and controller assembly.

 

[peter d]

Re: Motor control circuits

Re: Motor control circuits

Yes, as long as the control circuit is wired entirely with Chapter 3 wiring methods.

 

[templdl]

Re: Motor control circuits

Re: Motor control circuits

My first thought is that the wire must be 600v rated. Also, there may be some concern with regard to the control wires being run along side wires that carry significant current. As such depending upon how your control circuit works there may be a possibility that current could be induced into the control circuit causing it to be unreliable. The longer the run the potential for a problem increases. You shouldn't have any problem is your control circuit is energizing a contactor or relay coil.
It may not be a problem but should be something that is considered.

 

[don_resqcapt19]

Re: Motor control circuits

Re: Motor control circuits

Take a look at the FPN after 300.3(C)(1). The 24 volt circuit is an Article 725 circuit.
Don

 

[coulter]

Re: Motor control circuits

Re: Motor control circuits

Originally posted by don_resqcapt19:
Take a look at the FPN after 300.3(C)(1). The 24 volt circuit is an Article 725 circuit.
Don

Don -

I checked your references in the 05NEC. I'm still not clear on if you are saying its okay to use the same conduit as the power - or not.

carl

 

[tom baker]

Re: Motor control circuits

Re: Motor control circuits

You need to determine what type of Art 725 circuit the 24 V is. Class 1, two types, Class 2 or Class 3. The rules change depending on the class of ciruit

 

[colosparker]

Look at the control transformer to determine what class power source you have for the low volt wiring. If it is Class 1-yes, Class 2 or 3-no. Article 725.