# Mixed Voltages in same box CEC



## Nico0327 (May 3, 2021)

Good day. 
I want to know if I am allowed to use different Voltages in the same box. I want to install a box that will have 2 x VFD's with 600V and then I want to have a PLC (120V) that controls the VFD's through MODBUS. And then Sensor wires going in and out from the PLC. 24VDC. 
It is all for the same fan motors. 

I read somewhere that it is ok as long as the conductors are all rated for 600V? 
I am in Canada. So, If anyone cant direct me to the right code rules please..

Thank you

Nico


----------



## wiz1997 (Mar 30, 2021)

Just about every control panel I encounter at work has just what you describe, 480 VAC to VFD's, 120 VAC control circuits, and PROFIBUS communication.

Insulation rating of wires should be rated for the highest voltage.
Shielded cables are a must.

If voltages come from different sources the panel needs to be labeled with that information.


----------



## Nico0327 (May 3, 2021)

Thank you so much.


----------



## gpop (May 14, 2018)

Try to keep things separated where ever its possible. Most of our panels are 480vac and drives on the right, 120vac in the middle and 24vdc + coms on the left. Coms hardware is fairly bullet proof against 50/60 hertz which helps but a drives output can cause all sorts of issues so we try not to run them together in a panel.


----------



## MoscaFibra (Apr 15, 2021)

In the same control panel definitely common to have every voltage needed in there, if you are getting it field inspected, there are rules for separation of circuits, and how they cross. We used the industrial control panel and UL standards when building panels. We used the CSA control check list from C22.2 before all inspections and never had a real issue. 

That being said, depending where you are in Canada, getting a panel shop to build it can sometimes be cheaper than trying to do it in house.


----------

