John,
I'm somewhat with theweldor, why not a wire feed (no code). Faster with the right setup. Maybe root first if you want with the 6010. And I agree with the size other than I have often used 3/16 even for the root. Just turn it up a little more.
But your question was welder size. I would think that while a 200 would handle it, you are going to be pushing the max end. Especially for 100% duty cycle. So how steady are your guys at putting rod to rod. I usually run either an 300 or a Miller 500D. Don't like to be sitting on the machines max end for long periods of time.
Have a Great Day, Brent
By JTMcC 
Date 11-23-2008 01:05
Edited 11-23-2008 01:11
John do you have clamps? If not you can spend quite a bit of time getting the hi lo out of the pipe and getting a good fitup.
36" .500W, in a ditch box, with experienced people and suitable equipment, runs right around 35 - 40 minutes actual welding time, from 1 hour 10 minutes to 1 hour 30 minutes from swinging the pipe into the ditch to completion. That includes buffing the bevels, getting in the clamps, getting it spaced and welding it out and rolling up. That's two welders and two helpers.
That's a bead with 5/32" 5P+, a hot pass, and two full fillers with 5mm 8P+ and a 3 bead cap (which is what the gas companies are calling for these days).
A puddle cap isn't really any faster, maybe zero to 5 minutes max. You fill it quite a bit lower for a 3 bead cap. A 2 bead cap isn't any faster than a 3 and 3 looks slicker. To puddle cap it I'd add in a 2 bead strip on the side.
Those are welds that will be inspected and shot.
I'd figure on a 24" .500W at about 25 minutes welding time from start to finish using the same two welders and the same consumables.
If you use 3/16" 70+, you will have to fill more before capping. The 5mm rods really pick up some time for you.
The place to really beat some time out of the job is in getting fit up. I don't believe on .500W pipe that you will gain any by using wire, because you'll likely put the bead/HP in with stick and then switch over, then weld out with wire, that plus moving the feeders into and out of the ditch box eat up time. On .650W or greater it's probably worth the time tho. Just my opinion.
These are my numbers, keep in mind there are using very experienced PL welders/helpers. U'm confident in those numbers for our use, they're compiled between my experience and a friend of mine on well over a thousand welds, and they take into account varying weather and site conditions. Feel free to modify them for your situation.
JTMcC.
