Service change question

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shputnik

shputnik

Senior Member
Location
Utah
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Expert wirenut installer
When changing a 100 amp to a 200 amp service does the utilities upgrade/ increase size of thier service drop conductors?

I have often seem contractors just tie the new 200 amp conductors to the existing wires
 
We temp it back and if the power company decides they need new wires then that is their job. They have different guidelines then we do as they do not use the NEC.
 
Dennis Alwon said:
We temp it back and if the power company decides they need new wires then that is their job. They have different guidelines then we do as they do not use the NEC.
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I understand they don't follow the NEC but
Do you know what size wire, free air can be used for a 200 amp service? Curious why they wouldn't change it out?
 
shputnik said:
I understand they don't follow the NEC but
Do you know what size wire, free air can be used for a 200 amp service? Curious why they wouldn't change it out?
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They gamble that it will work using their historical data.

Since, they are usually right, it costs them less to risk the wires burning up than it would cost to always up grade.

They run their wires and transformers to the max.
 
Unless you tell them you are adding significant load, like instantaneous electric water heating or electric heat they assume it will have about the same demand it had before.
 
I've never once seen Nevada Energy in Las Vegas area change the overhead wires when I did a 100A to 200A service panel upgrade. I've also never had my customer call back about any issues.
 
MAC702 said:
I've never once seen Nevada Energy in Las Vegas area change the overhead wires when I did a 100A to 200A service panel upgrade. I've also never had my customer call back about any issues.
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How about when you went from 100 amp single phase to 200 amp three phase;);)
 
jumper said:
Ditto.

If they are right say 95% or more most times, why would they?

Same for trannies.

The odds are it will okay, they know this from experience.
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I added some HVAC load to a school one time. POCO had a run of 3 inch PVC with 500 aluminum to the building and CT metering at the building. Told them what I would be adding for load, I know they took into consideration the peak demand, how many hours it may run that way, and how many hours til it would have to cool down before next peak demand cycle. They decided to replace 500 aluminum with 500 copper based on what they figured, and upgrade 75 kVA single phase transformer to a 100 kVA. This conductor ultimately supplied 800 amps worth of multiple service disconnecting means on two separate buildings. I don't recall what actual NEC load calc would have been - too long ago, but would guess maybe 500-600 amps.
 
shputnik said:
When changing a 100 amp to a 200 amp service does the utilities upgrade/ increase size of thier service drop conductors?

I have often seem contractors just tie the new 200 amp conductors to the existing wires
Click to expand...

Electric utilities have their own set of rules they go by when it comes to them sizing their lines.
 
kwired said:
Unless you tell them you are adding significant load, like instantaneous electric water heating or electric heat they assume it will have about the same demand it had before.
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When I upgraded the service at my last house, the electrician strongly encouraged me to settle for a 150 amp upgrade. The original panel was 60 amp. His opinion was that the POCO would require a larger drop for a 200 amp panel that would have involved more expense on my side at the service drop. I bowed to his experience. Since the house was relatively small, built around 1929, with oil-fired steam heat and no central air, it didn't seem the 50 amp difference was worth pursuing with any vigor.
 
Gadfly, our POCO doesn't charge anything for upgrades, likely because they know they'll be selling more power. Also, it sounds like 100a would have been plenty, although the labor is the same either way.
 
LarryFine said:
Gadfly, our POCO doesn't charge anything for upgrades, likely because they know they'll be selling more power. Also, it sounds like 100a would have been plenty, although the labor is the same either way.
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It wasn't the POCO portion of the work that was an issue. The incoming service was attached to a fascia board and nothing else. The concern was I'd have to put in a mast to keep the POCO happy. As it was, the building department forced me to put a mast in anyway when I sold the house a few years later. And, like Tim Allen, I believe more power is always better!
 
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