Main electric service line too long?

[bebster]

To those who replied to my recent Cat5e pulling post -- thanks! I am also planning to run by main electric service line from the pole to the house. Total wire run is 400' from the pole to the main panel. My electrician is suggesting using "0000" gauge wire and burying it in 2 1/2" pvc conduit. Yesterday the electric company suggested that is too marginal and the voltage drop will be too high, and I should run a primary up close to the house and put a transformer pad there. Any suggestions? I was just about to begin digging the trench with my tractor next weekend!

 

[RobS]

I'd go with the electric company recommendation. Usually, that's their nickle anyway other than an upcharge for underground versus above ground wiring. Our house is about 500 feet from the utility lines and we have our own transformer box on the ground. Nice, bright lights all the time /forums/images/graemlins/cool.gif Neighbors are a bit closer and started with a pole hung transformer at the street. Had all sorts of problems with dimming lights and motor start ups. They got the electric co. to give them a transformer at the house and all is well /forums/images/graemlins/smile.gif

 

[bebster]

Here the electric company will give me a "2 pole" credit toward the transformer and 4' underground wiring. I suspect this isn't that much and the tab will be high. In addition to the cost, this will mean a 2 month delay since I'm sure they'll be slow on the design and construction etc.

I was able to find this voltage drop calculator.
Voltage Drop - Wire Size calculator

If I use copper 0000 gauge wire 400' long and drew the full 200 amps on the main panel, I'd get a 3.9% voltage drop. But I'm not sure if that's too much or not that bad.

 

[LarryRB]

I've done a fair amount of trenching for underground electric and have one question,, how are you getting away with 2 1/2" pipe when out in this side of Mass and CT for that matter, the electric companies require 4" schedule 40 at a minimum for anything over 200 feet... Also, the sweep to the poles now has to be in steel and no more PVC (just the 45 sweep)

 

[Farwell]

I would go with the power company's suggestion. Better to suffer a small inconvenience now over a large one later. Don't know if you have ever worked with 0000 cable, it is like trying to run three 3/4 inch steel water pipes into conduit. It can fit into 2-1/2 conduit but it will be a lot of work, require the right equipment to pull and someone that really knows what they are doing. I think three inch conduit minimum and probably better off with 4 inch if you decide to run your own wire.
Not sure of how the power company charges for installation in MA but in a lot of areas they charge for anything after the primary drop, if that is true in your case, you will save a big bunch of bucks. Check the price for 3ea 400 foot lengths of 0000 copper wire plus conduit and the hook up cost.
IMHP
Farwell

 

[Tim_in_IA]

definitely go with the power companies recommendation. You want that transformer as close to the house as you can stand it. I'm running 0000 at about 140' and this works well for 200amp service.

 

[CTyler]

</font><font color="blue" class="small">( I should run a primary up close to the house and put a transformer pad there. )</font>

Yes, that is what you want.

 

[cmuncy]

I have 1400' of primary running to my transformer pad 100' away from my house and 100' away from my shop. Best investment I ever made. I had to pay $4.00 per foot after the first 1000' of primary and that was it. All underground btw. That and nothing but 12 gauge wire and hire in my house and I don't EVER have a dimming problem. /forums/images/graemlins/cool.gif

 

[bebster]

My electrician is going to thread 10' lengths of pvc conduit 2 1/2" in diameter onto the 4-ought wire, and then glue them together. Kind of like making a beaded necklace on the ground, and then placing it into the trench that's 2' deep. He's an experienced guy so I want to give him the benefit of the doubt.

 

[midlf]

two thoughts:

Electric co. will have to spend more of their $ to do what they recommend. You will have a shorter run, thus less $. Electrician wants you to make a long run thus more $ to them. Think about it.

Second point. All conduit is to be installed as a complete system per NEC or NESC and then the wire pulled into it. If conduit is being threaded onto the wire something is wrong with this installation. Again, think about it.

 

[midlf]

Check down to the "power to pole barn" thread. It has a link to a cable size calculator. Using this calculator you would need 300MCM cable.

 

[Farwell]

midlf,
I agree with you. I also feel that on some things it is okay to take short cuts and do it the easy-cheap way but when it comes to wiring there are some serious potential consequences involved. I do not feel that any inspector or utility company worth their salt would allow the wiring to be passed if installed as described. If there is an accident caused by the wiring most insurance companies will not honor a claim that has code violations. They are always looking for loop-holes.
IMHO
Farwell

 

[chim]

Bebster, there are a couple things I'd look into:

1. How does the power company charge for their work? Mine brought primary to a padmount transformer near my house. They ate the charge for that because the transformer is set on the property line, so it could conceiveably serve another property next to mine. At the time, they told me if the transformer would be located entirely on my land, they would charge me for the 100 yard run from the road. They also ate the charge for the phone company's replacement of several poles along the road to get to my place. Power stopped a distance down the road from my place, but phone lines continued past it. The two utilities work together to some extent, and they decided to have the phone company upgrade their poles so they could run their power wires on them. My total cost was <$1.00>. The power company paid me $1.00 for the right of way for access to the transformer and the HV cable buried across my land.

2. I'd rethink the conduit size if the 4/0 was mine to maintain. In the event of a cable failure, re-pulling the run would be significantly easier with 4" pipe.

3. Making up the run like a "necklace" will be a PITA. If this is how your sparky plans on doing it, make sure he doesn't get sloppy with the solvent cement. Could damage the insulation.

5. There are some other good ideas already posted.

Good luck with your project........................chim

 

[CTyler]

While it could be done that way it seems like like more work to me in this case. It would be a lot easier to push the button on a puller, to each thier own. /forums/images/graemlins/crazy.gif

You REALLY should reconsider having the power company put the transformer near the house. My primary run is about 400' to the transformer. I had the transformer placed by my shop. The run from transformer to the house is 75'.

Is there a compelling reason you do not want to go this route?

 

[MikeD74T]

Balance the "cost now" vs "cost later". Is your electrician going to guarantee his installation for any length of time? I've threaded conduit over wire several times and it works great, but is the 2.5" conduit big enough & strong enough to pull out a defective wire & pull in a new one? or will you have to dig up the whole thing again & buy new conduit ? The power Co. owns their installation forever & has to maintain it. Keep your run as short as possible.

 

[Jim57]

Believe me... I would think about doing what the Electric Company suggested. The usage of power is more with voltage drop as well. So the closer the transformer the cheaper the power bill and will pay for itself in the long run. Not to mention what voltage dropage does to household appliances. It makes them not last as long.

Jim

 

[rambler]

Do as the electric company suggests & you will have a much better installation. In addition to all the hassles & questionable installation of your sparkie, you will get much, much cleaner power for your use. Long runs of 110v wire just eat up power as voltage drop. You will pay a tiny bit less every month for your electric bill with the meter closer to your use. Your electric motors will be happier over their lifetimes.

I'd go with the closer transformer every time.

--->Paul

 

[keeney]

RE: "I'd get a 3.9% voltage drop. But I'm not sure if that's too much or not that bad. "

If you switched the entire 200 amps on and off atthe same time, that 3.9% drop will be a very noticable dimming of the lights.

The human eye can percieve around a 1/2% change in brightness, so even if you only switch 20 amps on and off, that would be a 0.39% drop, which will be borderline. The things to worry about are appliance motor startup surges. I think an A/C can easily pull a 50 amp surge which will make the lights flicker every time the a/c cycles on.

I agree with the other poster - put in the primary to as close as your house as you can get it.

- Rick

 

[kevincook]

Bebster,

With all the money you have invested in your new barn so far you might as well bite the bullet and finish it correctly. I'd have the transformer placed close to the barn. You'll be happier in the long run.

What is the difference in cost?

Good Luck,
Kevin

 

[wroughtn_harv]

Bebster I think you've been out voted. :grin

I would only add two things. One, I'd strongly suggest you consider four inch conduit if you're going to go against all the wonderful advice offered. That way you at least have a conduit that will take your eventual upgrade.

Second, I'd go at least three feet of cover (forty two inch trench). Someday you might want another trench dug for something like lighting or irrigation. And you want the electric deeper than anything like that would ever need to go.l

Around here, north Texas, some of the electric co-ops will put their equipment in your trench if you dig it to their specs. You might want to see if that's an option (tractor time, hint hint).

Good luck and post some pictures of that barn.

please.