Farm wiring and service upgrade to house

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flick

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Hi folks,
I would like to verify a few things here before I quote a job. Customer lives on a farm. There is a yard pole with 200A breaker on the pole. Drop wires connect to wires at a weatherhead, down conduit to meter can, then 200A circuit breaker can, then back up in 2nd conduit out of top of breaker can, to weather head and attach to insulator rack to go to the various building, including the house.

That is the existing installation. The customer wants to upgrade the panelboard in the home with a 200A panelboard. It is aerial now, with three uninsulated conductors, and I'm going to change that out to 1/0 ns1 triplex with XLPE insulation (205A rating). Of course, new SE cable down to a new 200A breaker mounted on corner of house, then SER through crawl space to panelboard in basement. There is at present no ground rod at the yard pole, or at the house.

Here's the question:
I would like to run the GEC from the neutral at the top of the pole straight down the pole to the ground rods rather than come out of the meter can. I understand that this provides better lightning protection than bringing the GEC out of the lug in the meter can.

I'm also wondering if I should do the same at the house end of the triplex, ie. connect to the neutral before the weatherhead and run the GEC down the side of the house to the ground rods.

Opinions? Does this really make for a better installation as far as lightning/transient protection? Or should I just run the GEC out of the bottom of the meter can at the pole and the main breaker at the house?


Thanks for the help.

Flick

[ January 09, 2006, 11:02 PM: Message edited by: flick ]
 
Re: Farm wiring and service upgrade to house

Originally posted by flick:
I would like to verify a few things here before I quote a job. Customer lives on a farm.
Click to expand...
True.

Oh, wait - sorry... :D
1/0 ns1 triplex with XLPE insulation (205A rating).
Click to expand...
ATROEMI, is this copper? How do you come to the conclusion that 1/0 CU is worth 205 amps? Shouldn't you have 2/0 or 3/0 copper? Are you accounting for the 75? lugs you'll be terminating this in?

As for the lightning protection side:

250.24(A)(1) General. The connection shall be made at any accessible point from the load end of the service drop...
Click to expand...
I'd ditch the extra work for lightning protection, but I'm not a believer. I'd advise the customer to eat plenty of vegetables, say their prayers, and don't stay up too late, they should be fine. :D

[ January 09, 2006, 11:27 PM: Message edited by: georgestolz ]
 
Re: Farm wiring and service upgrade to house

No, not copper. Aluminum triplex. The 205A rating is from the manufacturer's spec sheet. I use Al/CU split bolt connectors at both ends to connect to 4/0 aluminum SE cable.

I don't know what the eating or sleeping habits of this customer are. I'll ask him tomorrow!
 
Re: Farm wiring and service upgrade to house

I'd be real curious to see that spec sheet - something's not right. Looking at Table 310.20, you'd need a 4/0 AL.

Perhaps that 205A is at 105?C or something?
 
Re: Farm wiring and service upgrade to house

Check out this link...hope it works. You have to put a check in the box that you want info on. "aluminum service drop, triplex", then hit the download button. It's a pdf file.

http://www.southwire.com

open product/catalog link on homepage. Sorry, first link didn't work.

flick

edited for bad link

[ January 10, 2006, 12:10 AM: Message edited by: flick ]
 
Re: Farm wiring and service upgrade to house

I just downloaded this file, I think it's the one you were talking about.

It's rated 205 amps @ it's 90? rating. The split bolts you're using are either 60? or 75?, so you can't use the full 205 amps. I'm not sure how to determine the 75? ampacities, though. My WAG would be around 180 amps, but that's purely a guess.

What temperature are splitbolts rated at, I wonder?
 
Re: Farm wiring and service upgrade to house

Not sure about all splitbolts, but the T&Bs are rated at 90 degree C. T&B/Blackburn APS41 is also UL listed and Al/Cu rated.

The 40AAW is rated for ACSR and therefore not UL listed since ACSR isn't rated by UL, but instead is rated by ANSI (I think). Anyway, that connector is rated for a 50C temp rise above the conductor temp. According to Blackburn engineering, the conductor fails long before the connector in this type of test.

flick

[ January 10, 2006, 08:39 AM: Message edited by: flick ]
 
Re: Farm wiring and service upgrade to house

In some cases, I would connect the GEC at the service point too, except for different reasons other than lightning. As far as the lightning protection goes, I would not be so concerned with the grounding aspect as much as I would in providing TVSS or other surge arresting equipment at the service and perhaps at the house panel.
 
Re: Farm wiring and service upgrade to house

If I understand You correctly....
the Electrical system You are dealing with is called a Farm Loop. One central metering point, and Customer owned overhead, or UG feeders from that location.
We have several farms in this area with similar setups.
The triplex cable You are considering is most commonly used by POCOs, & they size their conductors much differently than the NEC.
Here, I would have to install 4/0 Quadruplex, 4 wire cable, this will serve a Sub panel, & will have to meet the same conditions as a sub panel in any other situation.
These Farm Loops get a little ragged looking after a few Years. Would they consider putting this feeder UG ?
 
Re: Farm wiring and service upgrade to house

yes, the farm loop, or "Distrubution point" creates "sub-panels", but 547.9(B)(3)exempts the EGC where the requirements of 250.32(B)(2) are met.

edit: I wouldn't advise the use of this exception on a livestock farm. Go ahead and run the EGC, but on a strictly grain farm I go with 3 wire whenever possible. :)

[ January 10, 2006, 09:23 PM: Message edited by: hey_poolboy ]
 
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