Electrical Question? Squaring Off Corners

I got an estimate for installation of a 20kW propane backup generator. He figured the distance he'd have to run a wire (from the generator near the propane supply to a transfer switch he'd install near the main breaker panel) was 120 feet, which seemed way too high an estimate to me when he said it. The written estimate does not include his calculation of this distance. When I measured the distance it was about 72 feet. I emailed him about this descrepancy, and he said he needed to "square off the corners". I have no idea what this means. The path he'd take from the generator to the transfer switch would almost be a straight shot--there may be two "corners"/turns he'd have to make, but by my estimate the total amount of extra distance he'd have to make up would be about 6 feet.

What does this term mean, and why would he need 120 ft of wire to go 72-78 feet? He offered to allow me to purchase the wire and he'd take off that amount from his cost to me. That wouldn't really address the issue.

Better to be too long, than to be too short. If the wire is just one foot too short, your going to be buying yourself another roll. But, you are paying for all 150ft. Ask him if he will pay for the pieces he cuts off. Maybe that'll change his mind about so much extra on both ends.
When I had my powerlines buried from the street to the house, it was about 450ft. The electrician ordered 500ft of wire. He had a little to play with on both sides, but not much.

Most bid jobs come with the term square and perpendicular to the building. If everyone runs their stuff crossways, then the whole place looks like a piece of spagetti It is a common practice for things to be built square , plumb, level, and true. It is a craftman thing.That being said, the extra 40' of wire shouldn't be a big concern for the cost factor of a 20kw propane emergency backup generator. Scott

If you are burying the cables, you have take into consideration the depth of the trench on both ends. 2-3+ feet, so that adds extra length. Yes, better to have extra.

Thanks for the quick and helpful replies. So, he'll buy by the roll--makes sense. The generator would be about six feet from the house so little trenching required. From where it will enter the house, after a 65 ft run along a steel support beam, there's a drop of only about two feet to the transfer switch he'd put in.

The generator is air-cooled, so it'll be a bit loud, but the only window close to it will be a downstairs bathroom window.

I wouldn't think the guy would have 50% waste. He might be padding for the next job. !0 ' extra is actually a lot of waste. if he used a tape. Most of the wire I get has numbers on it denoting the footage. You can tell the starting footage and ending footage. Not all wire has the marks. If you don't trust him then he shouldn't be working for you. It's that simple really. There are some of my customers who wait for a long time for my schedule to ease off a little because they trust me. I would get more estimates untill you get the contracter that does it for you. Scott

Thanks for the info, Scott. I called another place today for an estimate.

I suspect if your contractor bought just the wire he needed instead of a spool, you'd be paying close to what he is asking now. It doesn't make sense to buy exact amounts at a higher price per foot when a quantity can be had. He should make an allowance for the difference.