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memyselfandI

memyselfandI

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Hampton Roads, Virginia
I have a 480V 3ph 4w 1000A service with a underground feed of 2 sets of 500mcm CU. I don't know what the calculated load was at the time of construction, but apparently is was sufficient enough to warrant a 1000A service.
230.90(A) reads that "Such protection shall be provided by an overcurrent device in series with each ungrounded service conductor that has a rating or setting not higher than the allowable ampacity of the conductor." If the breaker has terminals rated at 75*Cel, how can one get away with only running 2 sets of conductors when they would be rated at 380A each? IMO this is undersized and a third set needs to be pulled to satisfy this requirment.
 
Where is the official 'Service Point'? The place where the rule switch from the NEC to the NESC.

If the conductors you are asking about are covered by the NEC it sounds like there is a problem.

If the conductors you are asking about are under utility company / NESC control then there is no problem.
 
iwire said:
Where is the official 'Service Point'? The place where the rule switch from the NEC to the NESC.

If the conductors you are asking about are covered by the NEC it sounds like there is a problem.

If the conductors you are asking about are under utility company / NESC control then there is no problem.
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Good question. Sometimes it is the customers responsibility to install the service entrance conductors, most of the time it is the utility company. My guess is that it was the utility company because an electrical contractor would have sized the wires accordingly
 
Years back had the POCO want to drop 2- 4/0 Al to a 1200 amp service, 130' away. Customer was having extreme voltage drop issues with the POCO (100 volts to ground mid summer at high noon with previous 400 amp service 1-4/0 380 amp actual load per leg) Met with the engineers as the new load was going to be 750 amp. They agreed to upsize to 3-350 Kcmil per leg. Customer no longer had voltage drop issue.
 
memyselfandI said:
I have a 480V 3ph 4w 1000A service with a underground feed of 2 sets of 500mcm CU. I don't know what the calculated load was at the time of construction, but apparently is was sufficient enough to warrant a 1000A service.
230.90(A) reads that "Such protection shall be provided by an overcurrent device in series with each ungrounded service conductor that has a rating or setting not higher than the allowable ampacity of the conductor." If the breaker has terminals rated at 75*Cel, how can one get away with only running 2 sets of conductors when they would be rated at 380A each? IMO this is undersized and a third set needs to be pulled to satisfy this requirment.
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This more likely was installed by virginia power if it is cominig from the transformer. Usually we only will have to install conduit sweeps out of the CT cabinet or switchgear, and they bring the runs to transformer and pull wire.
 
benaround said:
When is the last time you saw the POCO install 500mcm copper conductors??
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Other then the fact they all deliver electricity I think all power companies are different.

There is a local power company here that only uses copper for under 600 volt overhead distribution.
 
I don't know...

I don't know...

What about the aspect that they use a different type of insulation and what of its values?
Does that not come into play, some stuff I've seen is equal or bigger than a half dollar ? ?
Sorry, I've never noted the Poco stuff... more...
 
Bob, Is the POCO located near the salt water areas, better said, do they use

the copper wire in areas away from the salt water area.
 
benaround said:
Bob, Is the POCO located near the salt water areas, better said, do they use the copper wire in areas away from the salt water area.
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You got it. :smile:

It is a municipal power company in a seaside town.
 
DAWGS said:
This more likely was installed by virginia power if it is cominig from the transformer. Usually we only will have to install conduit sweeps out of the CT cabinet or switchgear, and they bring the runs to transformer and pull wire.
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True. But there have been times that I was required to pull the service entrance conductors to the pad. Sometimes having to do with the distance inside the building to where they need to go. I would have to look at the blue book... or white book. They keep changing the colors. Heck I've even install 6" conduit for there primaries because they didn't want to. They supplied the conduit, I supplied the labor. I think i got the shaft on that one, but hey what are you going to do? They got you by the joules. :)
 
memyselfandI said:
True. But there have been times that I was required to pull the service entrance conductors to the pad.
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I does not matter who installs it, what matters is who controls it and where the official service point is.


cadpoint said:
What about the aspect that they use a different type of insulation and what of its values?
Does that not come into play, some stuff I've seen is equal or bigger than a half dollar ? ?
Sorry, I've never noted the Poco stuff... more...
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It is not much about how they rate the conductors, it's more about the real load.

The power company does not care that the NEC says a certain building will require a 1000 amp service.

The power company goes by it's long established history and data of actual building loads and provides the amount of conductor needed to serve the buildings actually needs and not the NECs calculated needs.
 
may I go back to square 1. I did not note in the OP if the service panel had a main.
Am I mistaken that if this is a 1000 amp MLO panel (or greater) and a computed load of less than 760 amps, then the installation would be Code compliant ?
 
augie47 said:
may I go back to square 1. I did not note in the OP if the service panel had a main.
Am I mistaken that if this is a 1000 amp MLO panel (or greater) and a computed load of less than 760 amps, then the installation would be Code compliant ?
Click to expand...
The panel is a 1000A MCB
 
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