Can you install two different voltage systems in the sam

[agoordeen]

Question: Does the NEC prohibit having 120 volt AC and 277 volt AC conductors in the same conduit?

Context: It has been proposed to pull a hot and a
neutral (120 volt) circuit in the same pipe as the 277 volt AC feeders that supply step-down transformer on the first floor. The step-down transformer on the second floor was cooked and a replacement has not become available. Right now, the receptacle on the second floor is dead and temporary power has been provided with the use of extension cords to the PLC controller. So, power (120 volt AC) would be tapped from the first floor step-down transformer secondary through the same pipe as the 277 volt supply circuit and up to the second floor to re-supply the dead receptacle in the controller cabinet. What do you think?

Is it a go for launch or not? Looking forward to your input. Thanks.

 

[ryan_618]

Re: Can you install two different voltage systems in the sam

Please read This thread and feel free to ask questions.

 

[pagano21]

Re: Can you install two different voltage systems in the sam

This should be ok. Keep in mind that the two different voltages need to be color coded to identify the 2 different voltages. Use the Industry standard for color coding. I assume there is branch circut protection on the recp. circuts.

Mike P. JW Wireman

 

[don_resqcapt19]

Re: Can you install two different voltage systems in the sam

Mike,
It does not appear that the circuits in question are multiwire branch circuits. The code in 210.4(D) only requires phase and voltage identification for the ungrounded conductors of multiwire branch circuits. It is a good idea to provide this type of identification for all ungrounded conductors, but not required by the NEC unless the circuit is a multiwire branch circuit.
Don

 

[ryan_618]

Re: Can you install two different voltage systems in the sam

Don: I was told (by Bill Adiss???), that there would be a change in the 2005 that would require this type of identification on non-multi-wire branch circuits as well. I hope it passes. I am told it was going through the process quite well.

 

[agoordeen]

Re: Can you install two different voltage systems in the sam

Thank you for your feedback.

Another question: Can we install a 120 Volt AC circuit in the same raceway with wiring used to monitor door status, fire release, power supervision, etc.? Please let me know if you need more information on the specifics.

 

[don_resqcapt19]

Re: Can you install two different voltage systems in the sam

agoordeen,
Probably not. We need a lot more information about the circuits in question, but in general fire alarm and othe low voltage circuits cannot be mixed with power circuits.
Don