Running line and load through same EMT without neutrals.

[Rjsutt]

I have a lighting control panel and I was curious if I can run my line and load through the same conduit without carrying the neutrals over as well. I have a neutral in the conduit for the circuit that feeds the panel itself. I’m thinking that would heat the conduit up, since there is no neutral. NEC references would be appreciated!!

 

[texie]

I have a lighting control panel and I was curious if I can run my line and load through the same conduit without carrying the neutrals over as well. I have a neutral in the conduit for the circuit that feeds the panel itself. I’m thinking that would heat the conduit up, since there is no neutral. NEC references would be appreciated!!

This is just the same as a switch loop. The key is that the line and load must be in the same raceway and is perfectly acceptable.

 

[Rick 0920]

Be wary of how many current carrying conductors that you have in the conduit. If the conduit from your wireway to your relay panel is longer than 24", you will still need to derate your ampacity because of the excessive heat that cannot dissipate.

 

[xformer]

300.20(A)

 

[steve66]

I’m thinking that would heat the conduit up, since there is no neutral.

In this case your "line" and "load" work very similar to a hot and neutral being in the same conduit. The current flows toward the control panel in one wire (the line) , and back in the other wire (the load).

The result is that the net current in that conduit is zero, just like having a hot and neutral in the same conduit.

 

[Rjsutt]

In this case your "line" and "load" work very similar to a hot and neutral being in the same conduit. The current flows toward the control panel in one wire (the line) , and back in the other wire (the load).

The result is that the net current in that conduit is zero, just like having a hot and neutral in the same conduit.

Thank you. I knew i was overthinking it. I feel like I’ve done it 1000 times before but all of a sudden I was like wait a minute lol

 

[qcroanoke]

In this case your "line" and "load" work very similar to a hot and neutral being in the same conduit. The current flows toward the control panel in one wire (the line) , and back in the other wire (the load).

The result is that the net current in that conduit is zero, just like having a hot and neutral in the same conduit.

Does that also apply to both traveller's and the switch leg in the same raceway?

 

[jaggedben]

Does that also apply to both traveller's and the switch leg in the same raceway?

Yes because only one traveler will be used at a time.

 

[LarryFine]

Does that also apply to both traveller's and the switch leg in the same raceway?

Absolutely. As long as the total current(s) in each direction equal, the net result is zero, just like with a GFCI current sensor.

 

[kwired]

This is all about magnetic effects on a ferrous raceway. If you had non ferrous raceway or cable it is not an issue and is allowed by NEC. 300.3(B)(3)

You do need to comply with 300.20(B) if entering a ferrous enclosure through separate openings though.