Pole Building -- Electrical Question

[psj12]

I used 1/0 aluminum wire to run 125 amp service 96 feet from the meter (direct bury cable). I wired it just like firefighterjim said and it works just fine. Go to http://www.csgnetwork.com/wiresizecalc.html to calculate needed wire sizes.

 

[ray66v]

It is perfectly acceptable here in Ohio! Tell me why it wouldn't be.

If it is a sub panel, it should be properly grounded back to the main panel.

There are some exceptions to this, in some places. However, it is a good practice.

My understanding is: You will bond the neutral, and ground, at the sub, in the 3 wire set up. And you don't bond them in the 4 wire set up.

 

[Inspector507]

It is perfectly acceptable here in Ohio! Tell me why it wouldn't be.

Because the 2008 NEC no longer allows it on a new installation if you're in an area that has adopted that standard.

 

[Pops15]

I used 1/0 aluminum wire to run 125 amp service 96 feet from the meter (direct bury cable). I wired it just like firefighterjim said and it works just fine. Go to Wire Size Calculator to calculate needed wire sizes.

Just because it works doesn't make it safe or legal.
Like Ray says if its a sub panel it needs to be grounded back to the main panel.
Some jurisdictions require a separate ground rod for the sub panel AND tie the sub panel ground rod to the main panel ground or main panel ground rod.

 

[hitekcountry]

Because the 2008 NEC no longer allows it on a new installation if you're in an area that has adopted that standard.

And for good reason Here's why.

The previous version of NEC allowed two grounding options in wiring from a main panel to a sub panel in an out building

First option (4 wires) was to run the two hot wires plus the neutral and a ground in which case ground and neutral WOULD NOT be bonded at the sub panel

Second option (3 wires) was to run the two hot wires plus neutral and no ground in which case ground and neutral WOULD be bonded at the sub panel.

And in both options a grounding rod must be installed at the out building and tied to the ground buss bar.

However the second option was ONLY ALLOWED if there was no other grounding path such as a water pipe or coax cable or anything that would be grounded at both ends, which would create a parallel neutral return path and allow current to flow in the ground wires. NOT GOOD!!

So why was it allowed before and not now? Because some one would wire according to option two which would be perfectly fine, then sometime later install some electronic gear that was connected to power at both ends, as an example I installed a second dish network receiver in the gym in my garage. Now the coax cable provided a ground connection from my house wiring system to the garage which was wired with the second option (3wire) and the neutral then had a parallel path for current to flow in the TV coax cable. Like I said NOT GOOD!!

With the new code this won't happen.

 

[rambler]

It is perfectly acceptable here in Ohio! Tell me why it wouldn't be.

It used to be, but NEC has changed, and only in some rural locations for farm buildings is a 3 wire 220v setup allowed.

Today, most of you will need to install 4 wires: 2 hot, 1 nuetral, and one ground wire to extra buildings as subpanels.

The neutral & ground wire will only be bonded one time at the main service panel. NO WHERE else should these 2 wires be connected together, or it sets up un-safe loops that defeat the whole point of the ground wire and actually make everything much more dangerous. In your lifetime, you hope the ground wire is never ever used; but if needed, it can save your property or life.

But only if it is wired properly.

Many people confused the neutral & ground wires, but they have very different purposes. The ground wire is the round, 3rd plug on a socket, and is a safety device only. The nuetral wire is one of the spade opennings, and is part of the energized circut. They are different, and should remain different.

Both of them do need to be grounded to ground - but only in one place, at the main box.

--->Paul

 

[Diamondpilot]

A cheaper route (since it is a long run) would be running 3 wires (2 hots and 1 neutral) (aluminum) and drive a ground rod at the new building for your ground wire (copper) from the new sub panel. And as SPIKER pointed out, do not bond neutral to panel. (sub panel will require a ground bar kit)

That is the way my barn is done also. We added a hot tub in 2004 that we had pre-wired when the house was built in 1997. The Spa Panel for the Hot Tub Required 4 wires but when it was pre wired in 1997 they only ran 3. We had to go back and snake a 4th #8 wire back to the main house panel and add a ground bar bus in the main panel. I wanted to just drive a grounding rod like my barn had but they said that was no longer acceptable.

Chris

 

[firefighter jim]

Thanks to all for the 4 wire explanation. Still somewhat confused but agree that the latest NEC should definitely be followed. I guess I need a newer code book! Jim

 

[Diamondpilot]

Thanks to all for the 4 wire explanation. Still somewhat confused but agree that the latest NEC should definitely be followed. I guess I need a newer code book! Jim

Yes, things change but the way things were wired using 3 wires and a grounding rod is safe and grandfathered in so I would not lose any sleep over it.

Chris

 

[wroughtn_harv]

I'm building a pole buidling in about two months and plan on running electricity to it before next winter. Would #10 wire be as good as I need and should I run two wires? Here is some more information:

• I plan on dropping in additional breaker in the house fuse box and connecting the pole buidling to the house and putting in a small fuse box at the barn
• The buidling will be about 400 feet from my house
• I will run lights most of the time and a fan in the summer and maybe a tv/radio
• I will also run a compressor and possibly a small table saw and small hand tools and probably a charger for my tractor on occasions.
• No plan to hook up heater as I have a wood buring stove

Is this going to burn up the wires or my house or the barn?

I'm running two hundred and fifty feet of service, 100 amp, to a barn. I'm using 1/0 for the hots and a 6 gauge for the neutral. For four hundred feet I think I would want to talk to the electric company about seperate service with the barn having its own meter.

 

[woodlandfarms]

Just for my own personal edification, can someone explain to me why the 4th wire is now required? Is it in case the nuetral gets cut the ground will still be active? Is it too much juice feeding back on the Nuetral and the ground is for extra "pipeline"? We have an old well that the previous owner took out. But he converted the electrical connection to a couple of 110 plugs. But it is two hots and a ground. I know it is not the safest but trying to figure out if it is worth my while to dig up 300 feet of cable to make a change.

 

[rambler]

Thanks to all for the 4 wire explanation. Still somewhat confused but agree that the latest NEC should definitely be followed. I guess I need a newer code book! Jim

I agree it's confusing. I had the farm backbone rewired - was ovehead #8 wires installed in the 1950's. Went to 3 underground wires, a 350 foot branch, a 400 foot branch with 2 100 foot spurs, and a 100 foot branch to the house. The transformer/ meter/ main box is in the middle of the yard. They set up 200 amps to most locations, with 60 amp to each building (11 of them) along the way.

Because of ag exemption, I could do the 3 wire, ground at each building. Three of the buildings have metal water pipes connectiong; didn't matter. That was all cool in my location, my setup with the central meter pole, my farm setup.

And so on.

Pro electricians set it up & did it; county inspector came 3 months later & looked at the main panel & 3 buildings, said it all passed, & put my sticker on the main panel. Good to go.

Basically you need to follow whatever code is in the books in your county, and make your local inspector happy - they might have their own ineterpitation of the code sometimes.... Local electrical people will likely get along with the inspector real well as in my case, and things will be bried & easy. Outsiders or self-done work will take a lot closer inspection and thought to get an ok......

The 4 wire deal is a new thing. Back in the 1950's, delivering electricity was the goal. Now a days a lot of safety is more of a deal. The ground wire/ circut is there ti bleed off electricity quickly; make fuses or breakers snap _right_ away, and allow the new fangled ground fault type equipment to work. It is best to have a wire going all the way around the whole electrical system that does nothing but ground any metal off to ground. And if it is grounded in several places, it can confuse that fancy equipment & create it's own backwards loops of electricy. So - it needs to be installed correctly, and not confused with the neutral wire.

--->Paul

 

[firefighter jim]

I agree it's confusing. I had the farm backbone rewired - was ovehead #8 wires installed in the 1950's. Went to 3 underground wires, a 350 foot branch, a 400 foot branch with 2 100 foot spurs, and a 100 foot branch to the house. The transformer/ meter/ main box is in the middle of the yard. They set up 200 amps to most locations, with 60 amp to each building (11 of them) along the way.

Because of ag exemption, I could do the 3 wire, ground at each building. Three of the buildings have metal water pipes connectiong; didn't matter. That was all cool in my location, my setup with the central meter pole, my farm setup.

And so on.

Pro electricians set it up & did it; county inspector came 3 months later & looked at the main panel & 3 buildings, said it all passed, & put my sticker on the main panel. Good to go.

Basically you need to follow whatever code is in the books in your county, and make your local inspector happy - they might have their own ineterpitation of the code sometimes.... Local electrical people will likely get along with the inspector real well as in my case, and things will be bried & easy. Outsiders or self-done work will take a lot closer inspection and thought to get an ok......

The 4 wire deal is a new thing. Back in the 1950's, delivering electricity was the goal. Now a days a lot of safety is more of a deal. The ground wire/ circut is there ti bleed off electricity quickly; make fuses or breakers snap _right_ away, and allow the new fangled ground fault type equipment to work. It is best to have a wire going all the way around the whole electrical system that does nothing but ground any metal off to ground. And if it is grounded in several places, it can confuse that fancy equipment & create it's own backwards loops of electricy. So - it needs to be installed correctly, and not confused with the neutral wire.

--->Paul

Paul and any other person in the know, I did NOT bond the neutral in the subpanel of my outbuilding that I fed with the 3 wire system a couple years ago. Should I leave it that way? I'm hearing conflicting stories (to bond or not to bond subpanels with 3 wire supplies). I've been going through my NEC book (1993 edition) and I can't seem to find the answer. Thanks in advance, Jim

 

[mlitt12345]

Paul and any other person in the know, I did NOT bond the neutral in the subpanel of my outbuilding that I fed with the 3 wire system a couple years ago. Should I leave it that way? I'm hearing conflicting stories (to bond or not to bond subpanels with 3 wire supplies). I've been going through my NEC book (1993 edition) and I can't seem to find the answer. Thanks in advance, Jim

I'm curious to the answer of this as well.....my polebarn sub panel is a 3 wire set up also and I just looked at it and the electrician that installed it bonded the neutral and grounds and it has a earth ground rod also. Is mine right or wrong?

 

[kennyd]

I'm running two hundred and fifty feet of service, 100 amp, to a barn. I'm using 1/0 for the hots and a 6 gauge for the neutral. For four hundred feet I think I would want to talk to the electric company about seperate service with the barn having its own meter.

Usually the Neutral is only de-rated one size-#6 for your Neutral sounds to small to me...It's OK for the ground.

 

[ray66v]

Usually the Neutral is only de-rated one size-#6 for your Neutral sounds to small to me...It's OK for the ground.

You can use a smaller ground wire on a sub panel. But, I have never heard of an undersized neutral. Since 1/2 the current flows on the neutral wire, I don't see how you can de-rate it.

As I have said, my understanding has been you do bond the neutral, and ground, on a 3 wire sub panel. I always have used the unbonded 4 wire method, so I have never been through an inspection any other way.

 

[Inspector507]

Paul and any other person in the know, I did NOT bond the neutral in the subpanel of my outbuilding that I fed with the 3 wire system a couple years ago. Should I leave it that way? I'm hearing conflicting stories (to bond or not to bond subpanels with 3 wire supplies). I've been going through my NEC book (1993 edition) and I can't seem to find the answer. Thanks in advance, Jim

Jim, if you have an existing 3 wire feed to a separate building, yes bond the neutral to the cabinet and make sure there is a ground rod installed. It's the best you can do at this point.
The NEC was changed because the old arrangement was causing current to be carried on the neutral conductor in a fault to ground situation. The ground rod does not make a "ground". It is just a method of bleeding off transient voltage, such as lightning. The earth is a poor conductor for a fault to ground to return to it's supply and will not be a low impedance path back to to the supply. The neutral conductor then must try to be that low impedance path.

 

[SPIKER]

the outbuilding (since it is separate bld) should have a ground rod installed. the panel bond/ground should be tied to the new/2nd bld's ground rod. It should not be tied to the Neutral in the Sub panel that is in the 2nd bld.

Inspector57 is an Ohio inspector if I'm not mistaken, I have not been in the house hold buis in a good while... Moved into industrial side years back and have sense moved to mobile equipment design...

I have a copy of 2008NEC but have not specifically checked on this issue, I know it was confusing on the 2005NEC when many of the 3 vs 4 wire changes started piling up.

Mark

 

[Inspector507]

the outbuilding (since it is separate bld) should have a ground rod installed. the panel bond/ground should be tied to the new/2nd bld's ground rod. It should not be tied to the Neutral in the Sub panel that is in the 2nd bld.

Mark, when a 3 wire feed was permitted to a 2nd building, a connection from the neutral to the ground was required. He does not have a ground coming from the main panel.

 

[dcyrilc]

It is perfectly acceptable here in Ohio! Tell me why it wouldn't be.

Not legal anywhere in the United States. NEC code violation. Also, that setup DOES NOT provide short circuit protection.

Even previous versions of the NEC required neutral and ground to be bonded together in a three wire system or seperated in a four wire system.

For safety, the grounding system MUST be bonded to the neutral, and is only bonded in one location. With a three wire system to the subpanel, if the neutral and ground are not bonded together, you have no overload or short circuit protection at the remote location. Code violation, unsafe, etc, etc...

With a four wire system to the subpanel, the neutral and ground must be isolated from each other. If they are connected together at the remote location with a four wire system, 1/2 of the return current to the main panel will be on the ground wire. Code violation, unsafe, etc, etc...

Any other questions?