Copper Or Aluminum Wire?

[Welshmom]

Another new hoop barn question.
Running about 200 total feet of new wire into new hoop barn from panel in adjacent barn. Burying wire in trench. Have an electrician going to put it in for me, but he's asked me to provide materials. He said I can get away with 8-2 copper wire, or #6 aluminum wire (3 seperate strands). This barn will only have a string of lights, and 4 outlets, and a heated hog waterer. Will be running maybe up to two heat lamps at a time in there, or small hand tools, etc.
I know the aluminum will be cheaper, but is it going to compromise safety or load capacity?

[oneokie]

Make sure your electrician uses anit-oxidant on the connections if you use the aluminum wire.

[jacqueg]

I am just plain superstitious on this question. I don't care what precautions anyone takes, I would suck it up and pay for copper.

[TnAndy]

Originally Posted by oneokie

Make sure your electrician uses anti-oxidant on the connections if you use the aluminum wire.

Do this, and it's no problem running the larger aluminum.

Anyone hung up on "copper only" should really consider silver wire.....way better than copper

[deaconjim]

I could go along with aluminum for a hoop house, but I would only use copper in a building where my family would be sleeping.

I would use aluminum & run 4 wires instead of three . Two hot wires , one neutral wire & one ground wire . Since you're running 200 feet & burying it in a trench you might as well set up for 220 as you might want it in the future . If I'm not mistaken the neutral wire can be one size smaller than the hots & the ground can be two sizes smaller than the hots .

[Sawmill Jim]

[QUOTE=TnAndy;4749213]Do this, and it's no problem running the larger aluminum.

Anyone hung up on "copper only" should really consider silver wire.....way better than copper [/QUote

Very true al used as an entrance wire is fine here we use direct burial unless going overhead then we use tryplex . Got lots of that on hand no silver though

[fishhead]

If you have pocket gophers make sure to put it in 1 1/2" schedule 40 pvc or larger.

I had to pull up $500 worth of brand new wire because of gophers. I never even got it hooked up before they ruined it.

[rancher1913]

unless you did it yourself, your entrance wire to your existing house is aluminum. power company's use aluminum to your meter and most run it to the breaker panel. its only on branch circuts--after the breaker--that homes use copper. most ranges are wired with aluminum. basicly it boils down to money, both copper and properly installed aluminum are safe. use the antioxident as said above and your good to go. use a licensed electrician and follow their advice. I'd be more worried about proper grounding than using aluminum wire.

[clovis]

Originally Posted by Welshmom

He said I can get away with...

I always cringe when I hear these words.

Life is short. Do it right the first time. Paying for quality only hurts once. Spend the money for upgrading the wire.

If you don't three years from now, you'll be saying, "Well, if we had the wiring that could handle it, we could easily triple the size of the hoop house...".

[rambler]

For a service feed, either copper or aluminum works well, no difference. Aluminum has to be bigger, but it costs less,s o is most often used by most anyone.

Be sure that the special grease is used, and that connectors are rated for use with aluminum wire, and all will be 100% fine with aluminum service wire.

Aluminum got a bad name when it was used in cheap houses for wire runs to outlets, lights, etc. The special grease wasn't used, too many times it was used with devices _not_ rated for use with aluminum wire, and so forth. Aluminum will oxidate without the grease (rust, basically) and it likes to swell & shrink much more than copper, and the little house wiring didn't deal with that well.

The bigger sevice wire, and the heavy duty connectors on the big service equipment, deals properly with these issues and aluminum is not a problem being used for the service run.

Now, for some unwanted advice:

It sounds like you are only wiring 120v out to the building? WHY???? (8-2 wire means you have a hot, a neutral, and a ground wire. If you ran a 8-3 wirre, you could have 220v, with 2 hot wires, a neutral, and thew 4th wire is the ground. 99% of the time you need the ground wire these days, there are some few loopholes for ag buildings but rarely can you get that by any more.) Run that extra wire, and get 220 out there. Then you can have 2 curcuts of 120 each, much much nicer, doubles your power for only running one extra wire - cheap way to double your power!

Also, you are spending money on trenching, you are spending money on an electrician, for gosh sakes, don't 'get by' with as small a wire as you can.

Those wire sizes you mention are too small for that distance. Lights will dim, motors will wear out trying to start with the bad voltage drop you are going to have.

Why cheat yourself? #6 al wire at 200 feet is actually only rated at 11 amps - very under powered.

#8 copper at that distance is only good for 11 amps also.

Very, very poor design. Does your electrician know how long the run is? I'd wory about an 'electrician' who did such poor design.

This all just sounds like you will end up with a real poor thing, and pay good money to get nothing useable, and have to redo it all over again in a couple years to do it right.

Seems a waste to invest that much money and not at least be running a 40 amp 220v service out there, you are just wasting the money you are spending, it takes very little more to invest in a bit more wire to do this right.

--->Paul

[Riverdale]

Go bigger on the wire, go with being capable of 220v and put in sch. 40 conduit.

You will thank yourself later.

[NostalgicGranny]

We used aluminum for our house. When the copper thieves hit while we were away, all they did was clip the wire and steal our shovels (they pawn em for $2 ea.) People down the road were not so lucky. The thieves hooked their truck up to it and ripped out the wire. Needless to say they had to shell out a lot of hard earned cash to repair all of the damage.

[tiogacounty]

Couple of thoughts from a guy who has been a licensed electrician for a few decades now. Code requirements are that you have a disconnecting means for all circuits in an outbuilding. Basically this involves switches at the entrance to the barn, garage etc. that can disconnect everything that is connected, outlets, lights etc...The easiest and often cheapest way to do this is with a small sub-panel at the door. Places like Home Depot and Lowes have really reasonably priced 100 amp twenty circuit panel with a few breakers included (under $75). The next issue is wire. I did voltage drop calculations a few different ways and a #8 copper or a #6 alum. will work for a basic 20 amp circuit. But the issue here is that you are spending a lot of money for the trenching and installation and doing an absolutely bare minimum job. I would dig a trench at least two foot deep. Install 1-1/2" pvc conduit in the trench. This will run about $90 for material and it's worth every dime. Direct burial of any wiring is just a problem waiting to happen. Now run 100 amp aluminum sub-panel cable in the pipe. This is know as 2-2-2-4 SER in the trade. It has three # 2 wires, two hots a neutral, and a #4 ground. It is roughly 7/8" in diameter and cost about $1.27/ft. This will give you a 100 amp sub-panel in the new barn for very little cost over doing a minimal job. This job is about the cost of the electrical labor and trenching costs, the costs to upgrade to a proper conduit install and a 100 amp sub-panel should be a few hundred bucks. Well worth it. BTW, for all of you reading this thinking.......BAH, we don't need no stinkin' electrical code, here are a few things to keep in mind. First, more townships and counties are requiring inspections are a requirement of a property sale, nothing like having to do major rewiring because you didn't follow the rules in the first place. Second, insurance companies are always looking for a way out of a claim. Having a switch at the door of a small barn to turn the receptacles off might seem like a silly requirement, and it is. However it may be just the reason an insurance company wiggles out of paying a claim when a heat lamp burns the place down.

[Oldcountryboy]

Ditto on going bigger! 100 amp underground alumimun 4-plex and a 100 amp panel box like tioga mentioned. You never know when you'll be wanting to add something later anyway. Will be nice to already have the power already there.

[rambler]

Or in 5 years, you want another building in this location. From the 100 amp service, you can jump over to the new building pretty cheap. With a 15 or 20 amp service, you don't have enough to service the 2nd building.

You don't even need the 100 amp box in your hoop building - you can get a simple $15 2-breaker box for now and only put one breaker in it for $4. You can do it cheap; but burrying the wire is spendy, and doing it a 2nd time to get it right is real spendy. Put a big enough wire in the first time, you can cheap-out in other ways that won't cost so much to 'fix' later.

Many of us know because we did so in the past or are fixing something a previous owner or parents did 'cheap' not long ago..... It's easy to spend your money I know, but - consider the costs of doing it wrong.

--->Paul

[clovis]

Well said, Tioga.

I ditto the thought about PVC also. I know a guy that ran over 100 feet to a barn, and laughed when I suggested it.

Just a few years later, the direct burial line has gone bad, mostly because he went cheap on the project. The entire project will have to be redone now, including the renting of another trencher, new wire, etc.

While I've never done it, I'm told that if you ever get a bad leg with wire in PVC, it is often possible to pull the new wire through as you pull the old wire out. True?

[tiogacounty]

Originally Posted by clovis

Well said, Tioga.

I ditto the thought about PVC also. I know a guy that ran over 100 feet to a barn, and laughed when I suggested it.

Just a few years later, the direct burial line has gone bad, mostly because he went cheap on the project. The entire project will have to be redone now, including the renting of another trencher, new wire, etc.

While I've never done it, I'm told that if you ever get a bad leg with wire in PVC, it is often possible to pull the new wire through as you pull the old wire out. True?

I have been building homes again for the last few years now. One rule I always stick to is, if it's run underground and it fits in a pipe, it goes in a pipe. I even run my well line in 2" conduit. I have had excavators tell me I'm a fool for wasting the money, until they did it the first time. A decade from now you can go to my jobs, dig a hole at the pitless adapter on the well casing and replace the well line, all the way to the pressure tank by sliding a new one in the 2" conduit under the yard, the basement slab and right to the pressure tank. Beats digging under the driveway and front porch to replace a bad line, eh? As for pulling a single wire out of a pipe? Sometimes you can. the issue is that, if you succeed you haven't had the opportunity to inspect the other conductors at the "scene of the crime". If there is a lightning strike or short that takes out a wire, it often does damage to the other wires. I really like to have all of them out of the pipe for a through inspection at that point. I hate to think that I walked away assuming that everything is fine, but guessed wrong. Remember however, that we all have some amazingly different conditions underground. direct burial wire fails for a few common reasons including varmints that are somehow attracted to an electrical field and chew wires to sharp rocks that will cut into insulation. IF, you are blessed will all the right conditions, such as, free of burrowing rodents and nothing but good clean sand to dig in, don't hesitate to skip the pipe and use direct burial rated cable.

[tiogacounty]

Originally Posted by rambler

You don't even need the 100 amp box in your hoop building - you can get a simple $15 2-breaker box for now and only put one breaker in it for $4.

--->Paul

This can create a few interesting headaches, but it certainly isn't impossible. The biggest issue is that you would need a box rated for 100 amps at the barn no matter how small and cheap it is, unless..... you derate the breaker at the supply end of the cable. For example by using a 30amp/ 2 pole. But, you have to see if you can actually get # 2 wire to fit the lugs of a smaller breaker. At the barn end you have the issue of trying to fit a 1-1/2" conduit into an undersized panel that logically would not have a concentric knockout for that sized pipe. Don't forget that when it's time to upgrade to the proper 100 amp panel, a lot of items now need to be replaced, including the breaker at the main panel. I don't think most folks see the value of standardization and product volume in things like electrical work. The sub-panel I cited in my post is an example. I bought a SQ-D 100 amp sub-panel with a 100 amp main and five additional breakers on sale for $49.95. A smaller panel, or an odd sized one can be twice that and come with no breakers. A 200 amp, three phase panel costs a few dollars more to produce than a standard residential one, but costs several hundred more at a supply house. I was doing the calculations on a job like this and discovered that the individual wires I need for a sixty amp panel were three times more expensive than buying 100 amp. 2-2-2-4 aluminum sub-panel cable. What I'm saying is that it's possible to spend more and get less if you stray from the common commodity items in this case.

[fishhead]

Originally Posted by clovis

Well said, Tioga.

I ditto the thought about PVC also. I know a guy that ran over 100 feet to a barn, and laughed when I suggested it.

Just a few years later, the direct burial line has gone bad, mostly because he went cheap on the project. The entire project will have to be redone now, including the renting of another trencher, new wire, etc.

While I've never done it, I'm told that if you ever get a bad leg with wire in PVC, it is often possible to pull the new wire through as you pull the old wire out. True?

All the wire that I have seen is twisted. That would prevent pulling a single wire.