Electric in to pole barn question

[debo1683]

I am working on wiring my pole barn and have a couple of questions ..

1. When I poured concrete I wasn't thinking ahead and didn't run any conduit through the floor. What is the best way to tackle this now that the floor is poured? I don't really want to do an LB on the outside of the building, so I guess I am looking at tearing up a small portion of concrete... What is the best way to go about this? I have a hammer drill and some fairly large bits ... I just planned on going after it with this...

2. I am grounding this panel separate from my main panel at the house. The run is about 100 feet and I am using aluminum wire. I have read a few differing opinions on whether or not I need to bond my metal siding to the ground bar. What is your opinion on this? I have installed an outlet and two lights outside. All their grounding wires do not touch the metal siding ...

3. When I do my grounding rod, does this need to run outside? Or can I put it in the hole that I will eventually be digging to get conduit through the building?

Hopefully I don't start any arguments with these questions. Sometimes electric can be touchy on here. I just want to make sure I am doing things correctly.

Thanks!

 

[murphy1244]

Better check your local codes.

 

[bucktaker]

Yes break a hole through your slab and line it with conduit, backfill it with concrete.

Run a ground wire outside and sink a good ground rod
do not bond or connect metal siding. Are you running 220 to your building?
place a breaker in the house and a main disconnect in the garage.

 

[debo1683]

Yes break a hole through your slab and line it with conduit, backfill it with concrete.

Run a ground wire outside and sink a good ground rod
do not bond or connect metal siding. Are you running 220 to your building?
place a breaker in the house and a main disconnect in the garage.

Yes, 220/240 to the building. I have a 100 amp panel in the barn with a separate grounding bar. I have already added most of circuits out there. Our electric code is is the 2008 NEC.

 

[grsthegreat]

I am working on wiring my pole barn and have a couple of questions ..

1. When I poured concrete I wasn't thinking ahead and didn't run any conduit through the floor. What is the best way to tackle this now that the floor is poured? I don't really want to do an LB on the outside of the building, so I guess I am looking at tearing up a small portion of concrete... What is the best way to go about this? I have a hammer drill and some fairly large bits ... I just planned on going after it with this...

2. I am grounding this panel separate from my main panel at the house. The run is about 100 feet and I am using aluminum wire. I have read a few differing opinions on whether or not I need to bond my metal siding to the ground bar. What is your opinion on this? I have installed an outlet and two lights outside. All their grounding wires do not touch the metal siding ...

3. When I do my grounding rod, does this need to run outside? Or can I put it in the hole that I will eventually be digging to get conduit through the building?

Hopefully I don't start any arguments with these questions. Sometimes electric can be touchy on here. I just want to make sure I am doing things correctly.

Thanks!

1. Agree with others, the only way (besides an outdoors LB) is to break the concrete directly below the panel. Real easy to do with chipping gun . Ive done it many times.
2. No need to bond building metal. It wont hurt if you did, but not necessary. Make sure the ground bus and the neutral bus are separate. Dont land any of the ground wires in the shop panel to the neutral bus.
3. you can install the ground rod in the same hole that you chipped. no issues with that. Run a #6 bare copper to the ground rod.
4. an added thought...run 4 wires to the house panel 2 hots, 1 neutral and 1 ground wire.


have fun

we argue over everything here....dont we

 

[Cat_Driver]

Why not bring power underground to the building foundation then 90 degree into the building then 90 up the inside wall?

Why does it need to be under the slab? If you keep everything above the slab you have better access fro repairs.

 

[debo1683]

1. Agree with others, the only way (besides an outdoors LB) is to break the concrete directly below the panel. Real easy to do with chipping gun . Ive done it many times.
2. No need to bond building metal. It wont hurt if you did, but not necessary. Make sure the ground bus and the neutral bus are separate. Dont land any of the ground wires in the shop panel to the neutral bus.
3. you can install the ground rod in the same hole that you chipped. no issues with that. Run a #6 bare copper to the ground rod.
4. an added thought...run 4 wires to the house panel 2 hots, 1 neutral and 1 ground wire.


have fun

we argue over everything here....dont we

Thanks. I am running 4 wires out there. You guys do argue a lot ... it is entertaining and informative ...

 

[debo1683]

Why not bring power underground to the building foundation then 90 degree into the building then 90 up the inside wall?

Why does it need to be under the slab? If you keep everything above the slab you have better access fro repairs.

I never thought about the double 90 thing. I just didn't want conduit running up four feet on the outside of the building. But if it is only 8 inches or so, that wouldn't be so noticeable. Thanks for the suggestion.

 

[LD1]

The double 90 thing is what I did for mine. Comes out of the ground about 8-10" and then into the building and up to the breaker box.

I would advise AGAINST doing it this way though. Hindsight is 20/20 but If I had to do over, I would have went through the floor. That 8" peice outside is a PITA to mow/weed whack around.

So unless you plan on putting a flower bed or something on that side of the shop, I'd punch through the floor since you are already equipped to do so.

 

[Iplayfarmer]

The double 90 thing is what I did for mine. Comes out of the ground about 8-10" and then into the building and up to the breaker box.

I would advise AGAINST doing it this way though. Hindsight is 20/20 but If I had to do over, I would have went through the floor. That 8" peice outside is a PITA to mow/weed whack around.

So unless you plan on putting a flower bed or something on that side of the shop, I'd punch through the floor since you are already equipped to do so.

X2

I ran a line to my chicken coop, and the 10" stub that takes the wire from the garage to the ground is a pain. I'm planning to upgrade my service to my garage. When I do, I'll dig a larger hole and drill through the floor.

 

[hr3]

Thanks. I am running 4 wires out there. You guys do argue a lot ... it is entertaining and informative ...

We don't argue much,, But we do agree to disagree alot,,,

 

[debo1683]

Thanks again guys. I thought about it and looked at stuff again last night and decided to put a hole in the concrete. Your help is more than appreciated ...

 

[ENG18LT]

Not sure if you have done it yet, if you haven't...... The hole in the floor only needs to be big enough to accommodate your conduit, as opposed to a larger chunk. Then when you did your trench outside just dig under the slab enough to get the conduit in and up. Once that is done backfill it with a small aggregate that will support the slab. Key is to disturb as little substrate as necessary to get the job done. Also you may want to consider filling the gap between the conduit and existing slab with "hydraulic cement", this will provide a better seal then standard concrete.

 

[billybobjimmyjoejack]

If the edge of your slab is not to thick and you have a large enough bit for your roto-hammer, you could drill straight down from the inside and then tunnel under the slab from the outside.
Drop the conduit from the top side into the trench, then add a 90 on the outside for you run inside the trench.
You can add a ground rod by just drilling a hole in the slab larger than the rod itself. No patching of concrete would be needed.
If you are concerned about water coming in around these holes I would suggest you drill your holes about 1/4" larger all the way around (1/2" dia. larger) and install your penetrations then use a urethane based caulking to seal the opening.
This will make the opening water tight and provide some flexibility between the penetrations and the concrete slab.

 

[Darrenone]

If you are running 4 wires from your house panel then why do you need a ground rod? You are grounded through your house service.

 

[gengine]

For 100' and 100amps, I would guess you are using 4-0 wire. If you are running conduit from the house to the barn, every turn you put in there makes it significantly tougher to pull your wire, so you have to be thinking about this. Our local power company won't do over three turns, wether 90 or 45 degrees. Check with you local codes on what I've said, don't take my word for it. That is what is allowed here. Just did kinda the same thing a couple weeks ago.

 

[Darrenone]

You should be able to use direct burial cable and just sleeve it through the conduit when entering the barn.

 

[powerpace]

Code for my metal sheathed pole barn on concrete slab required: (1) 2 ground rods outside the drip line ten feet apart with the clamps on the rods showing. (2) Ufer ground to the concrete slab rebars.

I would not break any concrete to put conduit in. Once you break the concrete it can cause all sorts of problems. Go with trenching around the concrete slab. Use gravel at the ground exit below the panel.

 

[grsthegreat]

for your information on the previous 2 posts.

1. NEC requires 1 additional ground rod for 100 amp subpanel in separate building (2 rods for 200 amps). It doesnt matter that 4 wires were run. the ground rod is still required.

2. I usually lay out the wires out along side the trench first THEN slip the conduit onto the wires 10 - 20 feet at a time. This is done prior to dropping conduit into tranch. This way i can run 100's of feet of wire and conduit myself and never have to actually pull the wires. It works slick and saves alot of labor costs. If the conduits HAVE to be installed empty, then i always upsize the conduits otherwise youll be hating yourselves later on. (and i have the use of pullers and pulleys and it still sucks to pull thru tight conduits.)

 

[powerpace]

The best advise will come from whomever is going to inspect the installation. It won't hurt to ask.