450' wiring conduit -how to assemble?

[JB4310]

I did the exact thing that you are planning. I ran electric service underground from a new pole at roadside to my barn 450' away. I had a guy dig a trench from the meter channel location at the corner of the barn to the new pole location. It was dug 2' deep and all spoils were placed on one side of the trench. The power company told me that if I did the install to their spec's they would take ownership of the line to the meter which would guarantee any repairs of the line would be their responsibility. To me that was a no brainer. Because of the distance they required that I install 4\0 2\0 triplex aluminum underground wire in 3" conduit and that I run a double run to insure that I got 230 volts at the meter. I purchased two 500' spools of the wire.

I think the key here is first you used 3" pipe not 2" and also sounds like a good idea about just pulling in a straight line, leaving the sweeps or other bends off till the end. Might even be able to use 2" doing it like that.

I would be a little worried flopping the assembly into the trench, with the possibility of breaking or cracking the pipe but I guess that stuff is pretty tuff. I am surprised you didn't have any trouble pulling that length of wire even in a straight line, gotta be pretty heavy!

The power company pulled mine uphill 100ft in 3" with sweeps and all in just a couple of minutes. It's the same deal with mine, I payed for initial install but they own it and are responsible for maintaining it in the future.

What is a double run?

JB

 

[kenstrac]

If I remember right the NEC says that the conduit must be installed and in place before wire is run in it

 

[bitternut]

The double run is two identical runs of conduit and wire. This was required by the power company because they only carry parts on their service trucks for 4/0 2/0 cable. If there was a problem with the line they would not any parts for repair if I had gone to a single run of heavier wire. This was all due to the voltage drop over the length of the wire. The meter socket had double the normal lugs for hooking up six wires. The power company dropped off the socket and I installed it. The siting engineer from the power company had already told me where the meter had to go and where to place the lines, etc. So I ended up buying 1000' of wire, 1000' of conduit, 4 sweeps and two expansion joints. Even with all the extra material I still saved half of what the power company wanted and what a couple of electricians quoted me for the job.

Not sure about the conduit having to be in place when pulling the wire though kenstrac. You might be right but that conduit is very tough stuff and to be honest I can not fathom how you could harm anything sliding it into a two foot deep trench. The power company actually did not require conduit if I had backfilled with sand. By using the conduit I was allowed to backfill with the native soil from the trench.

Actually the hardest or worst part of the job was the fumes from the glue coming out the end of the pipe. I did it on a sunny warm day and since I was at the high end of the pipe it acted like a chimney. All the fumes were coming out my end. Had kind of a buzz on by the time the wire was all pulled. The pipe was glued up several days before but with the hot sun on the pipe there was plenty of fumes. I would probably pull wire with the atv or lawntractor if I was to do it again. No fumes in the face that way.

 

[pat32rf]

I'd make sure I used the conduit and cable that the utility called for. They are going to inspect it and turn it on after THEY are happy. Other than that I'd follow Eddies advice...
Oh, and you can probably glue up 50' of conduit and pull it on in one piece...

 

[LarryRB]

Here in CT or MA,, you dig 36" down, minimum, lay in 4" of sand. Laying the pipe an and wire and feeding wire through each section, then gluing/taping is a matter of personal preference,,, In either case,, the ditch msut stay open, they must inspect schedule 40 or better piping, your required wire, that you have enough sand along the ditch to fill on top of the pipe after inspection, and,, you must have the bright red, electrical hazard tape laid one foot below final grade. Over the years have done thousands of feet underground. Not a hard or bad job to do, what makes it hard here is the inspections, If they can't make it and it pours rain, oh well is their attitude. Other than inspections, sand, and certain depth,, shouldn't be too hard to do, In any case, check with your utility company first for what they require in your neighborhood.

 

[lhfarm]

The power company came out yesterday. I already had a 320 amp base and a 200 amp cutoff heading to the house. They recommended changing the current lug arrangement, so I will add a second 200 amp cutoff to feed the barn. 4/0 in 2 1/2" conduit will get me 100 amp at the barn. He also changed my route and eliminated one bend.

Since we are changing the meter base, I now have to have a county inspection. 2 1/2" conduit is 3 times the price of 2". My costs are going up, but it will mean I can run more equipment if needed.

Since I'm in conduit, I don't have to have a marker. My understanding is I can have every thing in place (conduit covered) for the inspector. So I will pull the wire, get an electrician to set the cutoff box and service panel.

Thanks for all the advice. I'll post pictures when I get started.

 

[pat32rf]

For the price of the red ribbon, I'd throw it in anyway. You never know....

 

[LarryRB]

The power company came out yesterday.
Since I'm in conduit, I don't have to have a marker. My understanding is I can have every thing in place (conduit covered) for the inspector. So I will pull the wire, get an electrician to set the cutoff box and service panel.
Thanks for all the advice. I'll post pictures when I get started.

as another poster just wrote, for the price of red ribbon, it's not worth trouble. Here it is mandatory whether you like it or not. And why not? In the future what good is it if a backhoe goes ripping into the ground and no one is aware until the piping is snagged and now ruined anyway... For a five dollar piece of tape, for me it is added safety.

 

[Willl]

2 1/2" conduit is 3 times the price of 2".

Curious as to what 3" would cost ?

 

[podagrower]

Curious as to what 3" would cost ?

You don't want to know.
Lowes prices
2" $3.40 per 10'
2.5" $6.65 per 10'
3" 10.54 per 10' (That would be $474.30 before tax for this project)

300.18 Raceway Installations.
(A) Complete Runs. Raceways, other than busways or exposed raceways having hinged or removable covers, shall be installed complete between outlet, junction, or splicing points prior to the installation of conductors. Where required to facilitate the installation of utilization equipment, the raceway shall be permitted to be initially installed without a terminating connection at the equipment. Prewired raceway assemblies shall be permitted only where specifically permitted in this Code for the applicable wiring method.

For those who want chapter and verse. Conduit is supposed to be complete before wire is installed. I think the logic is that sliding metal conduit over wires could damage the insulation. PVC probably not as big a deal unless the jacket gets damaged by the glue, and since it was installed without the benefit of soap, you will probably never be able to remove it.