Outbuilding feeders and circuits from multiple locations

[JoeNorm]

Let's say we have an outbuilding with it's own sub-panel from a main house. The sub is not quite big enough to accommodate an addition that involves a new water heater(among other things). Can a circuit be run from a another location(closer) just to power the new water heater?

I recall there being a rule about not having multiple services, but this obviously is not that.

 

[letgomywago]

I think the only exception was for switching lights. I might be wrong though

 

[LarryFine]

The simple answer is no, you cannot have two feeders supplying a structure, regardless of the source(s).

 

[wwhitney]

In the 2020 NEC, you can have two feeders supplying the structure, if the two feeders originate at the same supplying panelboard. 225.30(B).

Cheers, Wayne

 

[letgomywago]

In the 2020 NEC, you can have two feeders supplying the structure, if the two feeders originate at the same supplying panelboard. 225.30(B).

Cheers, Wayne

But a large circuit and a feeder wasn't the intention it was to allow for grouping of disconnects of the feeders like from a 320 meter with 2 disconnects

 

[wwhitney]

But a large circuit and a feeder wasn't the intention it was to allow for grouping of disconnects of the feeders like from a 320 meter with 2 disconnects

OK, but under the 2020 NEC as long as the feeders originate in the same panelboard, and the disconnects at the building are grouped, you can run a second feeder if desired, rather than upsize the existing feeder. Just use a disconnect with OCPD at the building, then even if the circuit goes on to supply just one piece of equipment (the water heater), the supply to the building is still a feeder.

Cheers, Wayne

 

[letgomywago]

OK, but under the 2020 as long as the feeders originate in the same panelboard, and the disconnects at the building are grouped, you can run a second feeder if desired, rather than upsize the existing feeder. Just use a disconnect with OCPD at the building, then even if the circuit goes on to supply just one piece of equipment (the water heater), the supply to the building is still a feeder.

Cheers, Wayne

I feel like this is waiting for issues once there's more clarification in future code cycles

 

[wwhitney]

I feel like this is waiting for issues once there's more clarification in future code cycles

Why? It says what it says. It doesn't say "equal size feeders" or anything like that. If the disconnects are grouped and labeled as required, what's the problem?

Cheers, Wayne

 

[letgomywago]

Why? It says what it says. It doesn't say "equal size feeders" or anything like that. If the disconnects are grouped and labeled as required, what's the problem?

Cheers, Wayne

Wasn't allowed for a long time it's just asking for someone to say it's unsafe even if its completely safe and was only allowed to make it easier to be compliant with emergency disconnect rules.

 

[letgomywago]

I think that 1/0 and larger will always be allowed to be run this way.

 

[don_resqcapt19]

Wasn't allowed for a long time it's just asking for someone to say it's unsafe even if its completely safe and was only allowed to make it easier to be compliant with emergency disconnect rules.

Allowing more than one feeder to a second building has ZERO to do with the emergency disconnect rule in 230.85. While it applies to all second buildings, this change was aimed at second buildings that require a large amount of power. The idea is to reduce the arc flash hazard at the second building. The incident energy available at each of the multiple second building disconnects will be less than the incident energy that would be available at a single second building disconnect.