Class 2 circuit AC with light and power

[hhsting]

I have four fans 120V, 264VA single phase each and four heaters 24VAC, 40VA single phase each and 120VAC single phase for lights.

The panelboard is 120VAC so their is 3#10 from one 20A breaker to control panel then to fan, 3#10 from another 20A breaker to control panel to lights, 3#10 from one 20A breaker to control panel which has 120Vac to 24VAC transformer for heaters.

Now I have from control panel 3#10 for fans 120VAC, 3#10 for lights 120VAC and 2#12 from secondary if transformer 24VAC all in one conduit.


Questions:

1. Can you have 120VAC for light and power in same conduit as 24VAC?

2. 120VAC to 24VAC transformer require grounding?

3. Transformer 24VAC secondary has no EGC to heaters. Does it require EGC?

4. Would their be amapcity correction due to more than three current carrying conductor in the conduit all in one?

 

[don_resqcapt19]

I have four fans 120V, 264VA single phase each and four heaters 24VAC, 40VA single phase each and 120VAC single phase for lights.

The panelboard is 120VAC so their is 3#10 from one 20A breaker to control panel then to fan, 3#10 from another 20A breaker to control panel to lights, 3#10 from one 20A breaker to control panel which has 120Vac to 24VAC transformer for heaters.

Now I have from control panel 3#10 for fans 120VAC, 3#10 for lights 120VAC and 2#12 from secondary if transformer 24VAC all in one conduit.


Questions:

1. Can you have 120VAC for light and power in same conduit as 24VAC?

Not if the 24VAC is an Article 725 Class 2 circuit. 725.136

2. 120VAC to 24VAC transformer require grounding?

No. 250.20

3. Transformer 24VAC secondary has no EGC to heaters. Does it require EGC?

No.

4. Would their be amapcity correction due to more than three current carrying conductor in the conduit all in one?

The ampacity adjustment for more than 3 current carrying conductors applies to the power circuit conductors in the raceway. 310.15(B)(3)(a)

 

[tom baker]

Don is correct on question 1, for class 2, but if the 24 VAC is a class 1 remote control and power circuit, its wired with a chapter 3 wiring method and can be in the same raceway or enclosure as the power conductors. I have wired many 480V heaters (Q-Mark) that have a 24 VAC class 1 control circuit. Your 24VAC may well be a Class 1 circuit, take a look at Art 725 for the specifications.

 

[don_resqcapt19]

Don is correct on question 1, for class 2, but if the 24 VAC is a class 1 remote control and power circuit, its wired with a chapter 3 wiring method and can be in the same raceway or enclosure as the power conductors. I have wired many 480V heaters (Q-Mark) that have a 24 VAC class 1 control circuit. Your 24VAC may well be a Class 1 circuit, take a look at Art 725 for the specifications.

If the control circuit is a Class 1 circuit, Tom is correct that it may be installed with the power conductors, however that is only permitted where the control circuit is functionally associated with the power circuit. With four individual fans, that may not be the case. 725.48(B)(1)

 

[hhsting]

24 VAC are MC cables and 120 VAC light and power are MC cables but in same conduit. If 24 VAC is either class 1 or class 2 circuits MC cable still they have to be separated?

 

[tom baker]

Sincer you have mc cable you have the requiref seperstion, just check conduit fill for the MC cable

 

[kwired]

Don is correct on question 1, for class 2, but if the 24 VAC is a class 1 remote control and power circuit, its wired with a chapter 3 wiring method and can be in the same raceway or enclosure as the power conductors. I have wired many 480V heaters (Q-Mark) that have a 24 VAC class 1 control circuit. Your 24VAC may well be a Class 1 circuit, take a look at Art 725 for the specifications.

If the 24V control circuit is a class 1 circuit it must be run as class 1 wiring methods and terminate at devices that have other than class 2 or 3 ratings. Can not use CL2 cable where it is convenient or use typical class 2 only HVAC thermostat controls, would need to be class 1 wiring method all the way to a line volt rated thermostat.

 

[hhsting]

Is MC cable not acceptable wiring method in my case?

 

[kwired]

24 VAC are MC cables and 120 VAC light and power are MC cables but in same conduit. If 24 VAC is either class 1 or class

2 circuits MC cable still they have to be separated?

Is MC cable not acceptable wiring method in my case?

why are you running MC cable inside conduit, or is it just a sleeve for physical protection or a sort of chase through something already enclosed ? If either of those situations, then the MC cable is your wiring method and not a raceway method. MC is a stand alone method and nothing wrong with it.

If you were pulling general use conductors in a raceway then you might have issues with class 1, class 2, and/or power circuits all in same raceway, just depends on details.

 

[hhsting]

Its in PVC conduit underground come up outside canopy. I am not the person who is doing this. I am not the designer. Is their anything in NEC 2014 that says MC cable cannot be in conduit?

 

[david]

Its in PVC conduit underground come up outside canopy. I am not the person who is doing this. I am not the designer. Is their anything in NEC 2014 that says MC cable cannot be in conduit?

Is your underground conduit a wet location?

 

[shortcircuit2]

Maybe you can use this MC luminary cable...

http://www.afcweb.com/mc-metal-clad-cables/mc-luminary-type-mc-pcs/mc-luminary-jacketed-cable/