Two (2) 12/2 UF-2 as feeder to accessory structure?

[lakee911]

Can two (2) runs of 12/2 UF-2 be used as feeder to an accessory structure? Feed from a 2P 20A CB. Thanks.

Though odd, I can't find where the code would disallow it. Parrallel neutral is just redundant and not necessarily required.

 

[infinity]

Short answer is no. You cannot supply a separate structure with two circuits.

 

[Dennis Alwon]

Agree. A multiwire branch circuit would be allowed

Part II. Buildings or Other Structures Supplied by a Feeder(s)
or Branch Circuit(s)
225.30 Number of Supplies. A building or other structure
that is served by a branch circuit or feeder on the load side of a
service disconnecting means shall be supplied by only one
feeder or branch circuit unless permitted in 225.30(A)
through (E). For the purpose of this section, a multiwire
branch circuit shall be considered a single circuit.
Where a branch circuit or feeder originates in these additional
buildings or other structures, only one feeder or branch
circuit shall be permitted to supply power back to the original
building or structure, unless permitted in 225.30(A)
through (E).

 

[lakee911]

Short answer is no. You cannot supply a separate structure with two circuits.

What would make it two circuits? Single 2P breaker...

 

[infinity]

What would make it two circuits? Single 2P breaker...

It would need to be a MWBC to qualify as a single circuit so only one neutral.

 

[winnie]

IMHO only one circuit is permitted, but that can be a 'Multiwire branch circuit '.

In general all conductors of a circuit must be run in the same conduit or cable. However I believe you can use two non-metallic cables side by side for a single circuit.

Jon

 

[tom baker]

IMHO only one circuit is permitted, but that can be a 'Multiwire branch circuit '.

In general all conductors of a circuit must be run in the same conduit or cable. However I believe you can use two non-metallic cables side by side for a single circuit.

Jon

How does that meet the definition of MWBC and all conductors in the same raceway or cable?

 

[tallgirl]

It would need to be a MWBC to qualify as a single circuit so only one neutral.

But for how long? Sooner or later there are going to be "2" neutrals unless the MWBC feeds nothing but split-wired receptacles ...

If you look at ... the video ... eventually L1 and L2 are no longer in the same cable. All that's being proposed is separating L1 and L2, and a neutral to go with each, a lot sooner than the example Mike gives in ... this video.

 

[winnie]

How does that meet the definition of MWBC and all conductors in the same raceway or cable?

Wouldn't 300.3(B)(3) apply to UF cable? If I have 2 UF cables side by side, always passing through the same holes if entering metal enclosures, then I think you could use conductors from both cables to form a single circuit. Black from cable A to one pole of a double pole breaker, black from cable B to the second pole, white from either cable as neutral, white from other cable unused, and both grounds used.

-Jon

 

[lakee911]

Wouldn't 300.3(B)(3) apply to UF cable? If I have 2 UF cables side by side, always passing through the same holes if entering metal enclosures, then I think you could use conductors from both cables to form a single circuit. Black from cable A to one pole of a double pole breaker, black from cable B to the second pole, white from either cable as neutral, white from other cable unused, and both grounds used.

-Jon

That would be another way with two cables and no paralleling.

 

[LarryFine]

I would make the unused white permanently unavailable, perhaps by cutting it at the sheath.

 

[infinity]

But for how long? Sooner or later there are going to be "2" neutrals unless the MWBC feeds nothing but split-wired receptacles ...

I was talking about the supply conductors from one structure to another. The second structure would have a disconnecting means so you could have two neutrals after that point.

 

[tallgirl]

I was talking about the supply conductors from one structure to another. The second structure would have a disconnecting means so you could have two neutrals after that point.

I was picking nits.

MWBCs work electrically because the neutral currents cancel at the point where they are connected, wherever that is, even if it's inside the panel where the MWBC originates. They work financially because, as Mike says in that video, they save the cost of a wire.

This isn't an MWBC problem, it's a "separate structure" problem.

separate strutures disconnects

if a separate structure such as a garage is fed with a single branch circuit or a feeder to a subpanel is a disconnect required at the separate stucture or is the disconnecting means in the main building which feeds the stucture sufficient? Or say a pool house ,kennel etc?

forums.mikeholt.com

What's described is common data center wiring where 120/208 is run under the floor and single phase whips are taken off a box with no intervening disconnecting means. It's less common in pre-wired office cube partitions (another example given) because all of the phase conductors tend to be present. But for data centers? It's 120/208 Wye to a box under a rack, and if the rack doesn't need all the available power and only has 120 volt loads, all that's brought up through the floor is a single phase, with it's own neutral, and there's no disconnecting means below the floor, only at the PDU.