Two 20A GFI breaker circs (separate Neutrals) in 12" bury conduit.

[T-Stripes]

Want to bring two 20A/120V GFI protected circuits to a building in a shallow conduit. Table 300.5 wording allows "circuits," plural, at 120V or less, 20A. I am not installing a 3-wire, so not 240v, and I could even use two Phase A (or B) stabs for the breakers, avoiding a 240v additive voltage. I would install an EGC to the pull-out disconnect for these two circuits, to meet the "more than one circuit" requirement. Does anyone see a flaw in this reasoning, as it applies to Table 300.5?

 

[retirede]

Having 2 separate circuits may be violating 225.30.

 

[n1ist]

Why not bring a single multiwire (A/B/N) circuit?

 

[infinity]

Want to bring two 20A/120V GFI protected circuits to a building in a shallow conduit.

This is a separate structure?

 

[norcal]

The permission for 12" burial depth is requires 120V max & GFCI protected in a residential occupancy, so no multiwire circuits.

 

[infinity]

Certainly two or more 120 volts circuits all on the same leg would not be more 120 volts.

 

[AC\DC]

Certainly two or more 120 volts circuits all on the same leg would not be more 120 volts.

Never thought of that lol

 

[BarryO]

Having 2 separate circuits may be violating 225.30.

Run them as a MWBC so it's one circuit. Use IMC so you're using Column 2 in Table 300.5 rather than Column 4, so there's no "120 volt" limitation.

 

[retirede]

Run them as a MWBC so it's one circuit. Use IMC so you're using Column 2 in Table 300.5 rather than Column 4, so there's no "120 volt" limitation.

That’s what I would do, but my guess is he’s trying to use PVC, even though it’s not stated. It would be nice to hear back from the OP!

 

[infinity]

That’s what I would do, but my guess is he’s trying to use PVC, even though it’s not stated. It would be nice to hear back from the OP!

Sounds like burial depth in an issue. He could just run RMC with 6" of burial depth and no 120 volt limitations,

 

[retirede]

Sounds like burial depth in an issue. He could just run RMC with 6" of burial depth and no 120 volt limitations,

Exactly!

 

[BarryO]

Sounds like burial depth in an issue. He could just run RMC with 6" of burial depth and no 120 volt limitations,

Either RMC or IMC and you can use Column 2. That's what I did for my garden shed last year. Rotohammering a 6" trench in the volcanic rock here was bad enough for this old guy; anything deeper wasn't gonna happen.

 

[T-Stripes]

Why not bring a single multiwire (A/B/N) circuit?

300.5 limits voltage to 120v (per circuit?). I read that as "no multiwire" which can be seen as 240V...

Having 2 separate circuits may be violating 225.30.

I see the point, re 225.30. Following the wording (and each feeder terminates in a single disconnecting means, not more than six feeders shall be permitted) and m two circuits land at separate disconnects, labeled for their loads served, could this meet 225.30, as well as 300.5? Eventually, I will have to ask the inspector his opinion.

 

[T-Stripes]

The permission for 12" burial depth is requires 120V max & GFCI protected in a residential occupancy, so no multiwire circuits.

Right. No Multi-wire. So, two separate, with their neutrals. PVC conduit already in. (Customers stock. Didn't think about RMC for a feeder. Would have worked. Customer's cost/decision.) Too late. Approved today for the one GFI 120v cir.

 

[T-Stripes]

This is a separate structure?

Yes. Panel 35 ft away. If the GFI breaker trips, she has to go out to that panel. She was hooked on a shallow trench (she dug).

 

[T-Stripes]

Certainly two or more 120 volts circuits all on the same leg would not be more 120 volts.

I agree. Of course, Phase A/Phase A set-up has to be somehow maintained at the supply point, if the 300.5 rule can even bend this way. A universal breaker hold-down, sold by InterlockKit could potentially be the answer to maintaining position, like the top left and right breakers.
Great hold down, by the way. $10-$12 each, approved by my inspector, fits any panel.
The AHJ will have is say.

 

[T-Stripes]

Run them as a MWBC so it's one circuit. Use IMC so you're using Column 2 in Table 300.5 rather than Column 4, so there's no "120 volt" limitation.

I'm going to check on this idea. Have to move fast before customer buries. Thanks.

 

[LarryFine]

A universal breaker hold-down, sold by InterlockKit could potentially be the answer to maintaining position, like the top left and right breakers.

Or a tandem breaker.

 

[T-Stripes]

Or a tandem breaker.

Interesting.

 

[T-Stripes]

Or a tandem breaker.

I like that idea very much. Thanks Larry. I will consider my approach to the inspector. Finding the right way to ask a question can sometimes make the difference. Everybody wants to be considered, and that goes double for an inspector.