Buried pvc

[ScottChait]

Question about table 300.5
In column 4 it states that residential branch circuits rated at 120 volts or less with GFCI protection and a maximum overcurrent protection of 20 amps or less. In the 1st location specified it says it has to be 12” deep. My question is that it doesn’t Specify if it is 120 V to ground or Has to be an exact 120 V circuit. If I am feeding just a pool pump that is 240v which is 120v to ground. It is just a branch circuit and not a feeder so it will be GFCI protected from the main panel. Every other County I work in interprets it to be 120v to ground. I had an inspector in another County fail me saying that it is only 120v period. My thoughts are if you had 2 or 3 circuits in a conduit and they were all 120v circuits, you would still get 240v line to line if someone hit it with a shovel. He told me that if all 3,5 or how ever many circuits I have in the conduit are all 120v then I would be fine. But it’s the exact same thing, you are going to get 120v to ground and 240v line to line from any of the circuits that are on separate phases. So how is that any different? How is this supposed to be interpreted?

 

[wwhitney]

The exact column heading is "Residential Branch Circuits Rated 120 Volts . . ." and it doesn't say 120V to ground.

If you look at the Article 100 definition of "Voltage (of a circuit)" it reads "The greatest root-mean-square (rms) (effective) difference of potential between any two conductors of the circuit concerned." So a circuit with two wires 240V apart is rated (at least) 240V, and wouldn't qualify for using that column.

Cheers, Wayne

 

[infinity]

If you had (10) 2-wire 120 volt circuits in one raceway then the 12" dimension can be used. If you had one 240 volt circuit it cannot be used.

Column 4
Residential Branch
Circuits Rated
120 Volts or Less
with GFCI
Protection and
Maximum
Overcurrent
Protection of
20 Amperes

 

[ScottChait]

Thanks for the responses. I see that’s how it’s read, I guess I just can’t understand what the difference would be. The point of the burial depth is so someone doesn’t hit it while digging. If you have (10) 120v circuits if someone hits it then you you are still going to have a phase to phase short the exact same if you have (1) 240v circuit. Just doesn’t make any sense why one is allowed but the other isn’t that’s all. Because of that, I’ve most inspectors agree. So I’m just looking for clarification. Thanks for helping me understand this.

 

[infinity]

Thanks for the responses. I see that’s how it’s read, I guess I just can’t understand what the difference would be. The point of the burial depth is so someone doesn’t hit it while digging. If you have (10) 120v circuits if someone hits it then you you are still going to have a phase to phase short the exact same if you have (1) 240v circuit. Just doesn’t make any sense why one is allowed but the other isn’t that’s all. Because of that, I’ve most inspectors agree. So I’m just looking for clarification. Thanks for helping me understand this.

I think that the original intent was probably that there will be a single 120 volt circuit for something like a residential lamp post or a receptacle, you're correct about the phase to phase fault.

 

[Amps]

Thanks for the responses. I see that’s how it’s read, I guess I just can’t understand what the difference would be. The point of the burial depth is so someone doesn’t hit it while digging. If you have (10) 120v circuits if someone hits it then you you are still going to have a phase to phase short the exact same if you have (1) 240v circuit. Just doesn’t make any sense why one is allowed but the other isn’t that’s all. Because of that, I’ve most inspectors agree. So I’m just looking for clarification. Thanks for helping me understand this.

All 10 circuits could be on the same phase on different breakers in the panel. Measuring voltage between any two would be zero, measuring between any one and neutral would be 120 volts.