220 Volt Wire Run Info Needed

YuccaFlatsRanch · #1 09/21/12, 06:33 PM

My DW has decided to clean up my shop and has misplaced my handy dandy little blue book of knowledge that tells me the max runs of wire that I can safely do for a particular wire size.

I need to make a 350 foot run of electricity to my barn. I in all likelihood will never run more than 15 amps at 110 volts. HOWEVER, the wire that I have is 6 AWG submersible cable that is twisted together with two identical other wires. Since I am lazy and don't care to spend the amount of time to remove one of the wires, I came up with the bright idea to leave them all twisted together and run 220 volts out to the barn. What would be the max amperage I could safely put on the lines if when I got the run to the barn I was to run a small subpanel from the cable and break the 220 down to several 110 circuits. In other words, what size breaker do I need to feed the 350' run from?? About the max load I would ever have on the system would be a heat lamp for baby lambs or the shears for my shearer.

farminghandyman · #2 09/21/12, 06:49 PM

do a net search for voltage drop calculator, and it will figure it out for you,

looks like it could handle about 20 amps at that distance, http://www.elec-toolbox.com/calculators/voltdrop.htm

TnAndy · #3 09/21/12, 06:53 PM

WAY overkill for what you're doing, but #6 will handle 60amps. You don't HAVE to use a 60amp breaker...you could use a 50 or a 40....

You'll need 4 wires for 220v......2 hot, 1 for a neutral ( since you'll be breaking it out into 110v on the end ) and a ground.

a'ightthen · #4 09/21/12, 06:56 PM

Please explain the "6 AWG submersible cable that is twisted together with two identical other wires" .... total of 3 wires?

I'm thinking that that would be 2 for the phases ( 220) and another for the ground.

You are looking at ( for your purpose) 115 VAC with a "hot", a neutral and a ground .... there would not be a 220 without a 4th conductor ( or you would not be carrying the ground).

Is the cable AL or CU?

6 AWG is considerable for the tasks stated, so doable, but more info is needed.

arabian knight · #5 09/21/12, 07:04 PM

Quote:

Originally Posted by a'ightthen

Please explain the "6 AWG submersible cable that is twisted together with two identical other wires" .... total of 3 wires?

I'm thinking that that would be 2 for the phases ( 220) and another for the ground.

You are looking at ( for your purpose) 115 VAC with a "hot", a neutral and a ground .... there would not be a 220 without a 4th conductor ( or you would not be carrying the ground).

Is the cable AL or CU?

6 AWG is considerable for the tasks stated, so doable, but more info is needed.

Ya please do explain is it 3 wires or 2 wires wrapped up?
The submersible wire I am familiar with is ONLY 2 Wire and That Won't do for what you want to use it for for.

YuccaFlatsRanch · #6 09/21/12, 08:23 PM

These cables are submersible #6 copper rated TWWH. There are three separate cables that have been twisted into one bundle. I know about the 4th wire required for a ground. I did all the wiring for the service from the main breaker to my 200 amp panel for my house, but it was 12 years ago and I am old - memory, etc. Since there is too much work to untwist the bundle, I just figured I'd run 220 vs 110. The reason for the #6 is it was FREE.

a'ightthen · #7 09/21/12, 08:37 PM

Ye have the ability to run 110/115/120 ( whichever ye like to call it) or 220/230/240 .... but not the ability for both.

" I in all likelihood will never run more than 15 amps at 110 volts"
"About the max load I would ever have on the system would be a heat lamp for baby lambs or the shears for my shearer."
... stick it onto a single pole 20 amp breaker, tie it into a 20 amp GFCI receptacle ( or start off with a GFCI breaker) and call it good. Amperage can be managed better perhaps but your goals will be tended to with the above.

YuccaFlatsRanch · #8 09/21/12, 08:54 PM

Surely I have the ability to do both. Hookup is to a subpanel with each leg of the 220 to each side of the panel and the third wire as the common return/neutral - look at your home service - it's the same as in there. I do realize I need to run a separate ground wire to allow use of GFCI circuits and to provide a true ground, however the vast majority of homes built before the 80's have only the three wires (2 hots and a neutral). However in my barn where there may be some standing water or at least moist ground begs the use of a separate actual ground to prevent becoming part of the ground myself.

Now the question might remain - can I go to a ground rod close to the barn with the ground wire, or do I have to go all the way back to the service I am pulling the original power from??

a'ightthen · #9 09/21/12, 09:06 PM

Quote:

Originally Posted by YuccaFlatsRanch

Surely I have the ability to do both. Hookup is to a subpanel with each leg of the 220 to each side of the panel and the third wire as the common return/neutral - look at your home service - it's the same as in there. I do realize I need to run a separate ground wire to allow use of GFCI circuits and to provide a true ground, however the vast majority of homes built before the 80's have only the three wires (2 hots and a neutral). However in my barn where there may be some standing water or at least moist ground begs the use of a separate actual ground to prevent becoming part of the ground myself.

Now the question might remain - can I go to a ground rod close to the barn with the ground wire, or do I have to go all the way back to the service I am pulling the original power from??

All the way back for the ground ( 4th conductor) ... accept it as is ... or make the call and deal with it. There ain't no alternative. Ye are the one that asked ...

YuccaFlatsRanch · #10 09/21/12, 09:39 PM

I understand that I need the 4th conductor. If you read the original post you would find out that I was asking about how much current the #6 could carry for 350 feet. As far as the ground, that question was superfluous to the whole conversation. It will be interesting to find out if anyone else disagrees with you. A phone call on Monday to my Electric COOP might shed some light on the subject too. The ground on the 3 phase pump that went almost 700 feet (where the wire is from) was only an 18 gauge wire and I still have it available, as well as the other 350 feet of twisted #6 cables.

Oldcountryboy · #11 09/21/12, 10:28 PM

Now I'm not up to date on the NEC Code book since I don't do electrical for a living anymore. But use to you didn't have to have that 4th wire if your running the cable to a panel box. Instead you would run a #6 bare ground wire out the new panel and to a ground rod. But that might not be allowed anymore.

cnsper · #12 09/21/12, 10:49 PM

350 feet is not a great distance but like was posted earlier, 60 amps is the max. That would be the size of the breaker in the house but you already know that but for others reading later.

That calculator in the second post is wrong in the sense that it is doing a different calculation. What it is calculating is that if you want to have 20 amps available at the other end of the wire, you need to use a minimum of #6. That is not the max that #6 can carry.

On the grounding for those that will read later. Yes the ground needs to go back to the main panel, but in addition, you need a ground out at the barn and they need to be tied together and here is why. Lightening. Not for lightening rods but for safety and saving your electronics. If your wire gets energized by induction or a direct hit, electricity as you know takes the shortest path to ground. That path may very well be through your electronic components.

I used to install phone systems all over the country and you MUST ground both ends of an underground cable if you want any sort of protection. I have worked on systems with 1/4 to 1/2 million dollars in damage to them. It was because there was one cable that was ungrounded between buildings and the cable became energized. It just so happened that the phone system was the shortest path to ground.

I believe that this is the calculator that you are looking for. Voltage Drop Calculator because the amperage will not drop but the voltage can. I don't see any significant drop.

cnsper · #13 09/21/12, 10:52 PM

Good thing that the wire was free but I would not say it is overkill, the reason being is that one day you will be glad that you have the extra power out there.

arabian knight · #14 09/22/12, 12:54 AM

Quote:

Originally Posted by YuccaFlatsRanch

Surely I have the ability to do both. Hookup is to a subpanel with each leg of the 220 to each side of the panel and the third wire as the common return/neutral - look at your home service - it's the same as in there. I do realize I need to run a separate ground wire to allow use of GFCI circuits and to provide a true ground, however the vast majority of homes built before the 80's have only the three wires (2 hots and a neutral). However in my barn where there may be some standing water or at least moist ground begs the use of a separate actual ground to prevent becoming part of the ground myself.

Now the question might remain - can I go to a ground rod close to the barn with the ground wire, or do I have to go all the way back to the service I am pulling the original power from??

The Two wires are 110 Each.~! 3rd one neutral, 4th one Ground that is at the meter outside at the poll.
You get 220 at the service panel by getting One Fuse 110 one leg, one side of the panel and 110 from the second leg on he other side. But you are Running 110 into the house you do not have One Wire 220 unless you are running 3 Phase~!
And yes you can have that ground at the barn BUT get the REAL ground Rod. the 8 foot 5/8 dia. Copper Rod, just like they do at the meter~!

YuccaFlatsRanch · #15 09/22/12, 08:47 AM

No my house and my separate garage service each have two 000 wires providing 110 volts each, a 000 wire carrying the neutral and a #6 wire for the ground. I will be feeding the barn off of the garage service which is way less than half full. If you don't include the welder which is on a 50 amp circuit by itself, there is less than 75 amps of breakers installed in the whole service - plenty of room for growth. I oversized everything when I built the house and garage so that I wouldn't be short of electrical circuits. For instance my house service has 12 open single pole breaker positions in it and the garage probably has 25. The average constant load on the whole garage 200 amp service consists of 2 freezers, a refrigerator and a light or two. In reality, there are probably times when there is no load on that service.

YuccaFlatsRanch · #16 09/22/12, 08:50 AM

" Good thing that the wire was free but I would not say it is overkill, the reason being is that one day you will be glad that you have the extra power out there."

AMEN to that. Once you have power there is always a growth "of needs".

Really good thing the wire was free - I priced the wire out at somewhere between $2500 and $3000, In actuality I was given over 2100 feet of wire. #6 copper goes for well over a dollar a foot, and the price is not going down.

rambler · #17 09/22/12, 09:19 AM

Quote:

Originally Posted by YuccaFlatsRanch

I understand that I need the 4th conductor. If you read the original post you would find out that I was asking about how much current the #6 could carry for 350 feet. As far as the ground, that question was superfluous to the whole conversation. It will be interesting to find out if anyone else disagrees with you. A phone call on Monday to my Electric COOP might shed some light on the subject too. The ground on the 3 phase pump that went almost 700 feet (where the wire is from) was only an 18 gauge wire and I still have it available, as well as the other 350 feet of twisted #6 cables.

You asked about wiring a building with a total of 3 wires between them....

This allows 120v, OR only 220v. To do proper, true, 120/220v wiring to a building, you need 4 wires since about the year 2000. Before that there was an exception for agricultural buildings that did not have water pipes connecting different buildings.

So, the replies are right on track - you need the 4th wire to have a legal setup, or you are limited to 120v for practical use.

It will depend which NEC code version your local county/ city enforces, but if you don't have the 4th wire for grounding, you won't pass inspection, insurance, etc.

You need ground rod at the building, as well as the ground wire back to the main breaker, and you don't bond the ground wire to the neutral in your sub-panels.

--->Paul

rambler · #18 09/22/12, 09:24 AM

Quote:

Originally Posted by cnsper

350 feet is not a great distance but like was posted earlier, 60 amps is the max. That would be the size of the breaker in the house but you already know that but for others reading later.

That calculator in the second post is wrong in the sense that it is doing a different calculation. What it is calculating is that if you want to have 20 amps available at the other end of the wire, you need to use a minimum of #6. That is not the max that #6 can carry.
.

I'm a little lost on that comment, and before proving myself stupid, could someone elxplain what is meant here?

If a person wants a 60 amp service in a building, how does a 20 amp wire for the distance help them?

Edit: The vdc you linked to shows, if I enteded the data right, that his wires at 60 amps will drop 7.54%, which is not acceptable. You are allowed 5% drop, and most good electricians figure there will be 2% drop on the wores within a building, so only allow 3% drop for the service wire. So using your calculator, you could run 40 amps out there with the full 5% drop in the service wires, or much better is less than 30amp to get near the 3% loss.

I don't understand where you get 60amp possible - that shows over a 7% voltage drop for that distance, not good at all?

--->Paul

wharton · #19 09/22/12, 09:45 AM

Quote:

Originally Posted by YuccaFlatsRanch

Surely I have the ability to do both. Hookup is to a subpanel with each leg of the 220 to each side of the panel and the third wire as the common return/neutral - look at your home service - it's the same as in there. I do realize I need to run a separate ground wire to allow use of GFCI circuits and to provide a true ground, however the vast majority of homes built before the 80's have only the three wires (2 hots and a neutral). However in my barn where there may be some standing water or at least moist ground begs the use of a separate actual ground to prevent becoming part of the ground myself.

Now the question might remain - can I go to a ground rod close to the barn with the ground wire, or do I have to go all the way back to the service I am pulling the original power from??

Couple of serious misunderstandings in this thread, so far, some of which can be fatal. First, the #6 wire is best used for a single 20Amp/ 120 Volt circuit, in this case. The voltage drop, due to the 350' distance, gets substantial once you start drawing more than 15amps with this set-up. Second. you absolutely NEED a hot, a neutral and a ground for a branch circuit, or a sub-panel. The OP is proposing a sub-panel install, and is one wire short of doing it safely if he wants 220 volts. I therefore would strongly recommend that this wire is fed from a 20Amps single breaker at the house, and ends at a 20 Amp GFCI receptacle at the barn. Cheap, simple and safe. The practice of running three wire sub-panel feeds ended in the '86 NEC book for a good reason. It has to do with a difference of ground potential. This issue is created by going with a three wire setup and additonal ground rod at the barn. This is one of the many little understood grounding issues that leads to eveything from skittish animals that don't want to go in a barn, to getting electrocuted in a wet barn. Hope this helps?

wharton · #20 09/22/12, 10:09 AM

Quote:

Originally Posted by cnsper

350 feet is not a great distance but like was posted earlier, 60 amps is the max. That would be the size of the breaker in the house but you already know that but for others reading later.

Sorry, but in this case 350' is an enormous distance. Generally, when doing installs in commercial, or institutional costruction, I grab a calculator to check the engineers work once a branch circuit, or panel feeder run exceeds 175'

That calculator in the second post is wrong in the sense that it is doing a different calculation. What it is calculating is that if you want to have 20 amps available at the other end of the wire, you need to use a minimum of #6. That is not the max that #6 can carry.

You apparently don't have a solid understanding of voltage drop? The calculator is using generally accepted engineering standards to determine voltage drop over distance. It's about as far from wrong as it gets. If you want to explore this further, google the Southwire engineering calculator for more detailed results

On the grounding for those that will read later. Yes the ground needs to go back to the main panel, but in addition, you need a ground out at the barn and they need to be tied together and here is why. Lightening. Not for lightening rods but for safety and saving your electronics. If your wire gets energized by induction or a direct hit, electricity as you know takes the shortest path to ground. That path may very well be through your electronic components.

There is nothing specifically wrong with a ground at each end of a sub-panel installation as long as you understand the difference between grounding and bonding, the need for a four wire feeder cable, and the requirements of bonding the service as opposed to sub-panels

I used to install phone systems all over the country and you MUST ground both ends of an underground cable if you want any sort of protection. I have worked on systems with 1/4 to 1/2 million dollars in damage to them. It was because there was one cable that was ungrounded between buildings and the cable became energized. It just so happened that the phone system was the shortest path to ground.

This paragraph does nothing to help clarify the issues being discussed
]I believe that this is the calculator that you are looking for. Voltage Drop Calculator because the amperage will not drop but the voltage can. I don't see any significant drop

At a theoretical 60 amp draw, the various caculators I ran the numbers on call for 3/0 or 4/0 copper, depending variables. If you see no significant drop, you really shouldn't be online providing "advice"

.

Some serious lack of understanding here.