THE Contractor

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mannyb

Senior Member
Location
Florida
Occupation
Electrician
The contractor shall verify the exact method and requirements of service by utility companies during bidding and include all cost for a complete system in bid.... is this something that is normally on all BID proposals?? how would someone do that? i find it odd that contractor needs to do all the leg work for customer during bid. i understand why it needs to be don but why by people doing bids. the service drop on Bid is a proposed location and if power company doesnt agree after we won job then contractor would be responsible??
we recently found out on a job we won that the utility company changed the location of service drop to different location than what was on drawing. luckily i saw that it might be and figured in cost. i was really lucky. i thoughts about the process.
 

mannyb

Senior Member
Location
Florida
Occupation
Electrician
Around here that is the job of the general contractor. I only include what we do.


Dennis

i have a 200a 240v service that is 850' from pole. The print have 3-3/0 and #4 for ground because riser on pole is rigid. any idea why they put 3/0? would 3/0 keep voltage drop? its on engineer approved drawings. any ideas
 

Fulthrotl

~Autocorrect is My Worst Enema.~
Dennis

i have a 200a 240v service that is 850' from pole. The print have 3-3/0 and #4 for ground because riser on pole is rigid. any idea why they put 3/0? would 3/0 keep voltage drop? its on engineer approved drawings. any ideas

assuming this is a 240v 3 phase service, with no 120 volt to ground circuits,
using copper 3/0 would give you 9.43 % voltage drop.

if it's residential, you would be looking at a 120 volt to ground circuit.
200 amps on 120 volts, in copper, would be 21.78%

to get it under 3% would require 1,250 MCM copper.
to get it under 2% would require 2,000 MCM copper.

the hypress terminals for that size wire are about $200 each.
the press head for those terminals, in case you don't have one on the
truck, is $7,000

i'd a priced the wire, but nobody sells wire that large.......
you could use parallel 1,000 mcm, the wire cost for that would be
$89,250.

who'd you say engineered these drawings?
 

cal1947

Member
Location
waldorf,md
Tofer1947

Tofer1947

assuming this is a 240v 3 phase service, with no 120 volt to ground circuits,
using copper 3/0 would give you 9.43 % voltage drop.

if it's residential, you would be looking at a 120 volt to ground circuit.
200 amps on 120 volts, in copper, would be 21.78%

to get it under 3% would require 1,250 MCM copper.
to get it under 2% would require 2,000 MCM copper.

the hypress terminals for that size wire are about $200 each.
the press head for those terminals, in case you don't have one on the
truck, is $7,000

i'd a priced the wire, but nobody sells wire that large.......
you could use parallel 1,000 mcm, the wire cost for that would be
$
who'd you say engineered these drawings?
it would be cost affective to set a transformer close to the residence or building and step it down
 

gadfly56

Senior Member
Location
New Jersey
Occupation
Professional Engineer, Fire & Life Safety
it would be cost affective to set a transformer close to the residence or building and step it down

Heh. At $89K for the wire alone, ya think? At that price, it'd probably be cost effective to set up a stand-alone PV array with battery backup!
 

kenaslan

Senior Member
Location
Billings MT
Where is the meter? The power companies are exempt from the NEC. It also sounds like you are in a rural environment. Poles should be around 300' apart if allowed to run on a pole. That said, if the meter was at the pole, I would try to keep max VD, to the furthest receptacle, around 6 to 7%. If the meter is at the end of the 850' run it is the power companies problem to get the correct wire size. Remember, power companies NEVER size wire for full load. At an assumed 125A full load, (most probable), 850' @240V 1Ph is 6.5VD or 2.7% well within parameters. Also, what is the temperature correction factor and table being used? What insulation type on the wire/cable? I would ask the Engineer to verify his calculations (too many MEP engineers just pencil whip things and don't do the math, but then again, maybe he used ETAP to get the correct wire size). I would bid the job for what was specified and not look back. 3c 2/0 TC-ER copper retail is $8.25' $7012 total plus install and markup. I would do this all daylong if I owned a ditch witch for $12,000.00
 

JFletcher

Senior Member
Location
Williamsburg, VA
What is the actual load of the panel?


Where is the meter? The power companies are exempt from the NEC. It also sounds like you are in a rural environment. Poles should be around 300' apart if allowed to run on a pole. That said, if the meter was at the pole, I would try to keep max VD, to the furthest receptacle, around 6 to 7%. If the meter is at the end of the 850' run it is the power companies problem to get the correct wire size. Remember, power companies NEVER size wire for full load. At an assumed 125A full load, (most probable), 850' @240V 1Ph is 6.5VD or 2.7% well within parameters. Also, what is the temperature correction factor and table being used? What insulation type on the wire/cable? I would ask the Engineer to verify his calculations (too many MEP engineers just pencil whip things and don't do the math, but then again, maybe he used ETAP to get the correct wire size). I would bid the job for what was specified and not look back. 3c 2/0 TC-ER copper retail is $8.25' $7012 total plus install and markup. I would do this all daylong if I owned a ditch witch for $12,000.00

How are you getting 2.7% VD on an 850' run with 125A load on 2/0 copper? and why use copper instead of aluminum?
 

kenaslan

Senior Member
Location
Billings MT
oops Fat thumbed the keyboard. Too many jobs going on. 3/0 cu 15.5VD 6.5%. As most equip is rated for 230V I see no issue. Besides, 5% max VD is only a recommendation, and only where the NEC is required, not for utilities. The OP never stated if it was a utility or not asking for the job. Most equipment will work within 10% of rated voltage, with most having a rating of 230V. Besides, the utility company can change taps and increase voltage slightly.

The larger point, is if the drawings are sealed, the calcs are verified by the engineer, you install exactly what the engineer told you to install. If if fails after testing, and you installed what you were told to install, think of it this way, you will get paid twice to do the job. Once the way you were told to do it, and again to do it to fix any issues.

If you ask for the engineer to double check his math, no big deal, if you make an issue of it and say the engineer does not know what he is doing, in reality that engineer will blacklist you to the architect, the GC, and who knows whom else. Is it worth the loss of potential business? This is a business choice not an engineering choice.
 
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