Branch circuit from house serving waterer in barn in addition to barn service

[joemly]

Is it OK to have one branch circuit going from a house panel to a barn, when the barn already has its own separate service? This would be for the purpose of having that one branch circuit protected by a standby generator.

I have a house with a standby generator (automatic transfer switch), where the generator serves the whole house. There is a barn about 150 ft. away that will have its own separate overhead service. I would like to run a 120 volt, 7 amp circuit from the house to the barn just to feed a heated water container for horses, that would be protected by the generator in the event of a power outage.

Is this permissible under the Code? I can't tell from reading sections 225 and 230 of the NEC whether having these 2 separate sources of power in one building is permitted.

Many thanks for any help with this.

Joanna
Cornish, NH

 

[GoldDigger]

Is this permissible under the Code? I can't tell from reading sections 225 and 230 of the NEC whether having these 2 separate sources of power in one building is permitted.

Many thanks for any help with this.

Joanna
Cornish, NH

If you had a critical loads panel at the house instead of whole house, the ATS would be supplying some loads in the house but not others. This is not a problem, and I do not see it being a problem for the barn either. Under the specific condition that you put the same type of warning signs at the barn that you would have been required to put at the house in the same situation.
The NEC is concerned primarily with two normal sources of power at the same time.

230 does not apply directly to the barn since you have only feeders or branches (depending on whether there is OCPD at the barn or not) and not services. In addition the generator is a source of power, a supply, but not a service.

 

[joemly]

Thank you for your comments. I do not have a choice to create a critical circuits panel -- it is already set up so the generator supplies the whole house. So the branch circuit to the barn would have both constant grid power and generator backup power. And the rest of the circuits in the barn would be supplied by the main service to the barn.

Would that still be OK, in that case?

Thank you!

 

[kwired]

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).
For the purpose of this section, a multiwire branch circuit shall be considered a single circuit.
(A) Special Conditions. Additional feeders or branch circuits shall be permitted to supply the following:
(1) Fire pumps
(2) Emergency systems
(3) Legally required standby systems
(4) Optional standby systems
(5) Parallel power production systems
(6) Systems designed for connection to multiple sources of supply for the purpose of enhanced reliability

230.2 Number of Services:

A building or other structure served shall be supplied by only one service unless permitted in 230.2(A) through (D). For the purpose of 230.40, Exception No. 2 only, underground sets of conductors, 1/0 AWG and larger, running to the same location and connected together at their supply end but not connected together at their load end shall be considered to be supplying one service.
(A) Special Conditions. Additional services shall be permitted to supply the following:
(1) Fire pumps
(2) Emergency systems
(3) Legally required standby systems
(4) Optional standby systems
(5) Parallel power production systems
(6) Systems designed for connection to multiple sources of supply for the purpose of enhanced reliability

 

[david]

The way I read it you need a transfer switch at the barn. I do not see it as allowing the second normal branch circuit from the house.

I think I would allow it though under 225.30 (D)

 

[kwired]

The way I read it you need a transfer switch at the barn. I do not see it as allowing the second normal branch circuit from the house.

I think I would allow it though under 225.30 (D)

The way you read which section? Whether or not you feed directly from the generator or via the standby panel in the house, you still have an additional allowed supply to the barn. True during "normal operation" both feeds are essentially from the utility, but I don't see where that would be prohibited as long as there is an optional standby source and transfer switch involved somehow.

 

[Smart $]

The way I read it you need a transfer switch at the barn. I do not see it as allowing the second normal branch circuit from the house.

I think I would allow it though under 225.30 (D)

I don't see 225.30(D) as being applicable to this scenario, assuming the barn's service is capable of delivering the same voltage as the house-to-barn circuit. It doesn't seem to be for a different use, but the permissive statement isn't explicit...citing only one example, and leaving other "different uses" wide open to interpretation. As I see it though, the base premise to determine a "different use" would be determined more out of necessity than convenience.

The way you read which section? Whether or not you feed directly from the generator or via the standby panel in the house, you still have an additional allowed supply to the barn. True during "normal operation" both feeds are essentially from the utility, but I don't see where that would be prohibited as long as there is an optional standby source and transfer switch involved somehow.

I think the compliance determination in this matter rests on one fact... the optional standby system ends at the transfer switch.

 

[david]

I agree that the permissive language should have limited applications and it is wide open to judgment But isn't the example given for convenience of turning on a barn light from a house i do not see it limited to only non convenience uses.

 

[Dennis Alwon]

You may ask for special permission for this from the AHJ but I do believe it is a code violation. Perhaps if you installed a switch for the heater next to the disco for the building with a plaque explaining it was fed from another source the AHJ may okay it.

 

[kwired]

I agree that the permissive language should have limited applications and it is wide open to judgment But isn't the example given for convenience of turning on a barn light from a house i do not see it limited to only non convenience uses.

Op said the intent was for a heater in the drinking water for the horses - these are for keeping the water from freezing in cold weather. If "container" is just a bucket with a heater element it may not be such a big deal should it freeze, but if it is a permanent watering tank with automatic water control, it becomes a little more important to keep it from freezing or you will have water everywhere when it thaws out because water line or water valve will likely be broken, plus your livestock have no water when it is frozen.

Is it OK to have one branch circuit going from a house panel to a barn, when the barn already has its own separate service? This would be for the purpose of having that one branch circuit protected by a standby generator.

I have a house with a standby generator (automatic transfer switch), where the generator serves the whole house. There is a barn about 150 ft. away that will have its own separate overhead service. I would like to run a 120 volt, 7 amp circuit from the house to the barn just to feed a heated water container for horses, that would be protected by the generator in the event of a power outage.

Is this permissible under the Code? I can't tell from reading sections 225 and 230 of the NEC whether having these 2 separate sources of power in one building is permitted.

Many thanks for any help with this.

Joanna
Cornish, NH

 

[Dennis Alwon]

Yes the livestock may have no water but that doesn't mean much as the owner can opt to have a second genny for the barn. That would be the appropriate way to do it.

 

[david]

The way you read which section? Whether or not you feed directly from the generator or via the standby panel in the house, you still have an additional allowed supply to the barn. True during "normal operation" both feeds are essentially from the utility, but I don't see where that would be prohibited as long as there is an optional standby source and transfer switch involved somehow.

225.30 (E) (4)
I think the use of a transfer switch at the barn would define it as an optional standby source
If you run normal power directly from the house service how is this a standby source.

 

[Smart $]

I agree that the permissive language should have limited applications and it is wide open to judgment But isn't the example given for convenience of turning on a barn light from a house i do not see it limited to only non convenience uses.

I meant necessity vs. convenience of the circuit's power source, not the reason for the circuit. In the example of turning a light on in the barn from the house, it is a necessity that a circuit be powered by one source, either that of the house, or that of the barn.

On face value, it is not a necessity that the a heated water container in the barn be powered by the house under a normal service condition.

But we would eliminate that conditional barrier if controlling the heated water container from either the house or barn is desired. In other words, having a switch at the barn shows control from both locations is desired and all is well...

 

[Steviechia2]

Stick the plug on a 4x4 post next to the watering trough and not attached to the barn and you will be in compliance.
And if you want put a single pole switch for your disconnect.