Adding 400 Amps To Commercial Bldg

Bubbles

Just curious if anyone ever did a cost comparison of different 400 amp service setups. What I mean is whether to run 2-4/0 parallels in 2 conduits or a single 500 MCM setup. Whether to go with a nice clean multi gang meter stack (3 meters on this job) or go with a wire way, nipples, separate meter enclosures and such. The nice way to go seems to be about $2,500-$3000 materials with minimal labor and $700-$1,200 the other way with more labor. Does $280 per breaker sound right for feeder OCPD'S in the stack?? I know when you go 4" conduit price triples and so does everything else but labor should be lower.

Just curious what others do...

Bubbles

sorry. this one is 120/240V. 2 meters only need 100 amp OCPD's with #2 AL feeders at most and the other is 4/0 Feeder- 200amp.

Hopefully thats enough info

If anyone knows any good links to slightly used items such as disconnects and such that would be great as well. Another customer with Champagne taste and a beer wallet!

Magnettica

If I were doing it I would install it in parallel for the simple fact of less voltage drop and cheaper wire.

Ever have to push 500's up a 4" pipe for thirty feet?

It ain't pretty!

And as far the price comparison for 500's vs 3/0's in parallel I'm not even sure of the difference. Doing something like this in parallel is the way I was taught to do it in school.

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Bubbles

My gut says parallel but all the buildings next to this one are 1- 4" conduit with 400 amps. It doesnt really matter since there is more than one way to skin a cat. I was just thinking about doing it in 4" for a change. It might not be bad having one guy hand up the 500mcm conductor one at a time and drop it down the conduit to and out the LB. Then put the slack back in and down to the metering. I'll let you know if we do it that way and if it was a good move or not! Hopefully my arms hold out

hbelectric

I don't think i would run it in parallel and i don't recall ever seeing a 400amp run this way. The code book says what the min. wire size you can run in parallel, i don't have my book in front of me to look.

I don't think it would be wrong, but i wouldn't do it, unless it was engineered this way.

mdshunk

I run one pipe, mostly for the "clean look". The cost difference is about nil, and there's less labor due to one less pipe to make up and strap to the building. I don't really push conductors up these masts. I let them lay on the ground, put one end over my shoulder, and climb up the ladder and shove it down. A helper on the ground can help take the weight off. I do one conductor at a time, normally. Like you say, more than one way to skin a cat, and I suspect the preference varies regionally.

As far as the meter can/disconnect arrangement goes, you're prices seem a tad bit off to me, but I prefer to do the all one piece things. (2-200's, with disconnects, w/400 amp lugs more like 700 bucks) Not only does it look cleaner, but the added cost of the material seems to almost perfectly offset the labor that would have been necessary to do it with seperate pieces.

I guess there's no "right answer" to this one. Just whatever you fancy doing, and whatever you can squeak into the customer's budget best. I might suggest you draft one big RFQ for all the material to do it both ways, and fax it around to see where you stand at this particular moment in time.

Magnettica

Minimum is 1/0, 310.4.

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Bubbles

Well, were doing it with 2 sets of parallel. 2" EMT Weather Couplings and the rest. The reason is we have a customer with champagne taste and a beer wallet and EMT IS allowed where were at. I would of Preferred Al but it was $300 dollars more for the amount we needed. I like to carry it up as well and just let gravity takes course. Its a 28ft drop to the LB's than a bunch of maneuvering with some sweeps. I got a new estimate and it was a 400 amp rated bus with ability for 2-200 amp mains with 2 meters all in one. I'll see how it goes keep track of time and material than next one do it the other way and see how that ends up. BTW A litte off topic. Customer just added 8 treadmills to the second flr when I asked them a month ago and they said none for sure. Well, I guess that could potentially add ?? 10-16 amps per treadmill at full tilt in peak season?? Anyone know any actual treadmill amp draw numbers. I generally know they can draw a good 15ish amps but they don't even know which ones they are buying yet.

Thats all

mdshunk

A buddy of mine finished up a new Gold's Gym, and their treadmills were 9 amps at 240V. I only know this because I helped him size buck-boost's because they only had 208.

Resi treadmills are a good dedicated 15 amp circuit. My wife has a pretty decent one downstairs that says 11 amps on the dataplate.

Magnettica

I would treat the treadmills as a continuos load but I'm not sure if the code does.

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Bubbles

What I'm worried about is we already ran one 4/0 feeder to whole second flr

Load AC 65 amps FLA
6 Treadmill (Large Person on all at same time) 60ish amps
30 amps lighting

155 amps (plus incidentals) worst case summer with large people all running at same time plus whatever else they through at me. Might have to have them sign a waiver showing them what they got or another couple thousand to make it a 3 gang meter base run new feeder and set a new panel. Since they have beer wallet I'm sure it will be the cheaper. I might stop at a gym today and set up an amprobe and ask a large person to get on tread so I can run some test.