Is multi-feed to a pole barn sub-panel allowed?

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Old 04-14-10, 07:59 AM
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Is multi-feed to a pole barn sub-panel allowed?

I built a pole barn where the shed was. It had a 30a 2-pole (#8 THHN) feed to a sub-panel. I ran another conduit with #6 THHN to the barn, which is adequate for my needs, but my question is can I connect the L1 of each feed together, to the new sub-p breaker, and same with L2. With a 100A main breaker in the sub, if a load drew more than either of the main panel feed breakers (a 30A and a 50A), it/they would trip.

Is this done? Or, if I wanted more than 50A, should I install a second sub, fed from the 30A circuit, for other branches?

Unrelated question about tamperproof receptacles; do I need them for a detached pole-barn/garage? I say no, but I know someone who built an attached garage, who has to change them out to the tamperproof type.
 
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Old 04-14-10, 08:06 AM
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Originally Posted by Will S. View Post
but my question is can I connect the L1 of each feed together,
No, the old #8 feed must be abandoned. For many reasons, the code allows only one feeder circuit per outbuilding. Additionally, parallel conductors are not allowed in this situation so they cannot be combined into a single feeder.

do I need them for a detached pole-barn/garage? I say no, but I know someone who built an attached garage, who has to change them out to the tamperproof type.
No you should not need them in the pole barn. An attached garage is part of the dwelling which is why they are required in that case.
 
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Old 04-14-10, 02:06 PM
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Thanks. Yes, of course. I wasn't thinking ahead. I am sure one of the main concerns would be the potential hazard of backfeeding to the load side of the breaker in the main panel.

Will either abandon the #8THHN, or install a second sub-p in add'l capacity is ever needed.
 
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Old 04-14-10, 08:09 PM
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you could put a outdoor subpanel on a large post in the yard and then run the 8 into it and throw a bunch of outlets on it.

that would keep you from having 3 feeds to a single building.
 
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Old 04-15-10, 07:09 AM
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Originally Posted by Will S. View Post
Thanks. Yes, of course. I wasn't thinking ahead. I am sure one of the main concerns would be the potential hazard of backfeeding to the load side of the breaker in the main panel.

Will either abandon the #8THHN, or install a second sub-p in add'l capacity is ever needed.
The #8's must be abandoned or moved for use outside of the pole barn. A second sub-p in add'l capacity inside the pole barn is not a legal option.

As Braether suggested, a viable use for that #8 feeder is to an outdoor load center for outdoor use only. Another possibility could be to feed a secondary shed if you had one in mind. Only one power source per building, though, so the #8's cannot be used in any way in the pole barn since you've replaced them with the #6's.
 
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Old 04-15-10, 08:20 AM
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Two other possible uses for the old wires are as an inlet for a generator or for an RV hookup.
 
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Old 04-16-10, 01:52 PM
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OK, thanks for the guidance on that. Since this is, among other uses, my RV garage, I will use those 8's for a dedicated RV power/welder receptacle. (My old Sears welder requires a 2-pole 30A circuit, so that would work out just fine.

Is it correct, then, that the only breaker for that circuit, would be the one in the main panel in the house, (which is where it already goes)?
 
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Old 04-16-10, 02:53 PM
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You would have to locate it outside tho on a post or another building ....and plug the RV into the plug on the post... only way you can do it as far as I know...in most circumstances you CANT have 2 different feeders IN the same BUILDING.

But if you put a treated 6by6 in the ground run the feedier into a outdoor sub panel with conduit.. put in your required ground rod.. add whatever recps you want...then your good to go..
(just a nice option you could also put it on a garden shed or similar)
 
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Old 04-16-10, 08:55 PM
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For your situation per NEC codes you can not have two feeder circuits running in the building { there is a extempt but it is not used in your situation }

But becarefull with old 10mm˛ {#8 AWG } if you going have both welder or RV circuit really you only can use one of the two due the welder is typically straght 240 volts while the RV do use straght 120 volts so you will run into a issue.

The reason with old 10mm˛'s conductor if you have full 4 conductor then you may get away with it if you have legit two pole breaker otherwise if you have three conductors then no you must chose one but not both.

Merci,Marc
 
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Old 04-16-10, 09:42 PM
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For your situation per NEC codes you can not have two feeder circuits running in the building { there is a extempt but it is not used in your situation }
Thanks for posting in that manner. The exceptions of a single source to a building are important but rarely, if ever, encountered in residential work.
 
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Old 04-17-10, 07:01 PM
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Originally Posted by french277V View Post
For your situation per NEC codes you can not have two feeder circuits running in the building { there is a extempt but it is not used in your situation }

But becarefull with old 10mm˛ {#8 AWG } if you going have both welder or RV circuit really you only can use one of the two due the welder is typically straght 240 volts while the RV do use straght 120 volts so you will run into a issue.

The reason with old 10mm˛'s conductor if you have full 4 conductor then you may get away with it if you have legit two pole breaker otherwise if you have three conductors then no you must chose one but not both.

Merci,Marc
Yes, you're right of course. RV 50A 'shorepower' uses two 120vac legs (L1, L2, neutral & ground), a 4-terminal receptacle), but does not use 240v inside the RV.

Welding/compressor outlet uses only 240v; no neutral (3 terminal recp.)

My "old" #8 to the shed is actually not really very old, and is 3 - #8 and 1 - #10 THHN in 3/4 buried pvc. The new pull to the pole barn is 3 - #6 and 1 #10 THHN in another buried pvc.

Wishing I could use that #8 for something in the building, as I am not permitted to have a second out-building (shed, etc.), and the RV will be IN the building.
 
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Old 04-17-10, 07:22 PM
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Well if it was on a pole outside within a few inches of the barn you could probably run the connection for the RV outside to the pole without violation.

Going a bit more out of the box since the old is 4 wire you could run both a plug for the welder and RV from a subpanel. You'd just have to be careful to watch the RV load when using the welder.
 
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Old 04-18-10, 05:30 AM
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Ray, how many breakers am I limited to in the sub-p? I seem to remember something about 6, either singles or doubles. If that's correct, I will probably want to go from the panel to the RV recp in the back of the building, and then from there to the welder recp near the front. (building is 36x48').

The current draw from the RV will be low, very low, as I will rarely be running the heavy draw appliances like the 2 A/C-heat pumps, elec water heater, etc. I want to keep it plugged in for battery charging.

The building will also have 8' H.O. flourescent lights, 2 electric door openers, and 6 receptacles along each sidewall, and an entry door light. Oh and front and rear outside LPS fixtures, and a recept on the back ceiling for a future propane furnace.

So I will be at 6, if not more.
 
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Old 04-18-10, 07:30 AM
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Ray, how many breakers am I limited to in the sub-p?
Yes, six breakers unless you have a main breaker in the panel or are feeding it through a disconnect.
I will probably want to go from the panel to the RV recp in the back of the building, and then from there to the welder recp near the front. (building is 36x48').
The receptacles can not be in or on the building. That would be two feeds. My suggestion was to put the receptacles on the pole and plug in there.
 
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Old 04-18-10, 11:27 AM
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Appreciate the reminder, but I was speaking about running to the RV receptacle, then to a welder, from the sub-p, and abandoning the #8 feed, as was originally suggested. That was I would only need one double pole breaker in the subm for both RV & welder.
 
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Old 04-18-10, 08:06 PM
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Its totally up to you but I think you really might wanna put a RV recep on a post in the yard then you can park the unit outside and camp at home...haha... OR a bunch of yard outlets for weedwacking, future electric mowers Christmas lights ect ect...
 
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