400A or 300A farm irrigation pole service?

[tortuga]

I need help looking at a couple of ways to do a farm irrigation service pole. Three phase is out of the question so the farmer would like a "400A service" for future expansion.

No loads or pump other than a 7-1/2 HP single phase pump, a refrigeration truck that occasionally may be plugged in. I believe the refer truck is a 30A twistlock 240V 1 phase. Service is on a pole in a field. I suppose he could add several green houses or another pump and truck in the future.

So far I am thinking 18 Foot clearance since we have a commercial truck and a farm.
The Class 320 meter base I got is rated at 400A non cont. lugs are rated for 1 600kcmil or 2 250kcmil. However when I figure a 400A set I get:
1 set of 350 XHHW AL
400A Service 320A Continuous = 4 CC
Amps 80% Fill
350AL XHHW75?C 250 200 0.5166
Number of Sets 2 400 1.0332 Total Fill

Neutral size 250cmil XHHW75?C 205 164 0.3904
Number of Sets 2 328 0.7808 Total Fill

3" Conduit Mast. EMT since it is a pole.

This is inconsistant with common 400A meter base lugs?

I could also do 1 set of 500 Kcmil copper since I do not have a calculated load over 380A.

I find it strange that the 320A Meterbase lugs are rated for 2 AL 250's. Since this would only be a 328A Service. However the power Co usually sets a 75KVA transformer which would only be 312A.

I convince him 300A service would be enough.

What do you guys typically install for such a farm pole?

 

[ceb58]

You could, to save your self some time and work set a 400amp meter combo on a frame next to the pole. Let the poco come down the pole and feed it underground. The meter combos come with 1- 200amp breaker already installed, just buy another 200 and install for future sub panels if they go with greenhouses. It also has a 8 space buss that is rated for 100amp. You could feed the existing pump and install a TL recp. for the refg. truck.

 

[Cow]

I've built frames(or stanchions) off of poles before if the power co. doesn't have pots on them. If they do, then I'd build a seperate stanchion away from it and feed it underground like Ceb said.

I would think a 400 amp meter combo would work well in this situation, but you'll have to make sure you don't need a terminal bypass meter. That would really throw a wrench into it, I don't even know if that is something they'd make in a meter combo that wouldn't be outrageously expensive.

 

[kwired]

Install 400 amp switch or breaker and wireway or splice box large enough to accomodate future additions. You can install switches or breakers for these future loads if you wish but outdoor feeder taps are allowed unlimited length.

This is inconsistant with common 400A meter base lugs?

Every 320 or 400 meter base I have ever installed, only had studs installed and you supply your own lugs based on what conductors you are going to install.

 

[hurk27]

Install 400 amp switch or breaker and wireway or splice box large enough to accomodate future additions. You can install switches or breakers for these future loads if you wish but outdoor feeder taps are allowed unlimited length.



Every 320 or 400 meter base I have ever installed, only had studs installed and you supply your own lugs based on what conductors you are going to install.

I guess this can be done many ways, 320 meter at the end of a R-3 wire ways is one method then you can put what ever under the wire way, 400 amp meter combos can be a fast install but pricey, I usually try to stay with two 200 amp main breaker panels, off a 320, which could feed future loads and give you plenty of breaker spaces, but I cant see the need for all these breaker spaces, but technically feeding another building from this service would not require another disconnect as you can put double hole lugs in the 320 and run from the extra set back into the ground to the other building and hit a service rated main breaker panel in it as you would need to anyways, I have put triple hole lugs in a 320 but it get a little close between them, and finding the right ones that will work can be a pain, but at least double hole lugs are readily available and could be the best way by setting the meter in the middle of two 200 amp main breaker R-3 panels, all on one back board, if you have the ability to set poles I would suggest going under ground to a point safe from farm traffic then up the pole for the utility to run their drop to, they might even do this part for you if you present a safety reason?
and if you do use a R-3 breaker panel, try to get a copper buss version, as they hold up better with the moisture, and you dont get buss stabs burning off.

 

[suemarkp]

Looking at your original calculation, can't you do the 80% derating for 4 current carrying conductors from the 90C ampacity column (you'd need XHHW-2 wire though)? I think that would solve the problem.