Service lateral ampacity.

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emf10

Member
Location
Southeast PA
I was looking at a single family residential service today and the service lateral conductors on the supply side of the meter were #2 AL Type USE or RHW or RHH or XLPE. The load side of the meter is Type SE 4/0 AL to a 200 amp disconnect and 200 amp panel. Is this the gauge normally used for 200a service lateral supply conductors here (southeast PA, Excelon / Peco) or are they undersized?
 
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480sparky

Senior Member
Location
Iowegia
electricalperson said:
thats usually how it is around here. i never really see the power company run conductors sized to our NEC tables. goodthing our problem is after the service point

I don't call them conductors, if the POCO installs them. I call 'em fusible links. :grin:
 

emf10

Member
Location
Southeast PA
480sparky said:
Who put them in?

If you did, you need to size them per NEC.

POCOs have their own set of rules.

I don't know who put them in, it wasn't me. The panel looked sub-par so I was concerned whoever installed the panel maybe didn't upgrade the service laterals to what they should be, or if they are the Poco's responsibility.


480sparky said:
I don't call them conductors, if the POCO installs them. I call 'em fusible links. :grin:

Thats what I was worried about :) .
 
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LarryFine

Master Electrician Electric Contractor Richmond VA
Location
Henrico County, VA
Occupation
Electrical Contractor
EMF, if you're talking about the conductors that land on the line terminals of the meter itself, then you're most likely looking at a non-permitted service upgrade. The meter was pulled by who-knows-who, the load-side conductors were upsized along with the panel, and the meter was plugged back it.

I've seen it a lot, including a couple of electrical fires, where an upgrade was sold along with a central A/C installation, probably also not permitted or inspected. In both cases, the house had recently received glowing (pardon the pun) accolades by a private home inspector just before being purchased.

In one of these cases, there were no cable connectors of any kind, even the service cable, there were no grounding electrodes, and the 10/2 NM feeding the water heater caught fire during a storm. Somehow, the incoming neutral became energized, and the water-heater EGC was grounded through the water pipes.

Added: If anyone wtill wonders why water-pipe bonding has to be sized per the service rating, there's a good reason.
 
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iwire

Moderator
Staff member
Location
Massachusetts
Come on guys, do you normally see power company service laterals burning up? :-?

It is not that the power company overloads the conductors, it is that the power company knows the real load of the building they are serving and the NEC service you put on the home is far over sized.

The power company has much more accurate data about the real loads on a service then any of us or the NEC.
 

iwire

Moderator
Staff member
Location
Massachusetts
LarryFine said:
EMF, if you're talking about the conductors that land on the line terminals of the meter itself, then you're most likely looking at a non-permitted service upgrade.

I have no idea why you would say that?:confused:

Fill me in, because where I am those conductors on the line side of a service lateral meter would be power company conductors.

As far as the power company is concerned the size of the service the electrician chooses to install is pretty much irreverent.
 

72.5kv

Senior Member
On average the poco will size thier equipment at 30-50 percent of what the NEC specify. In some cases that same #2AL will be used on a 400amp service. Rule of thumb is expect to see 50 percent whatever your values are.
 

Dennis Alwon

Moderator
Staff member
Location
Chapel Hill, NC
Occupation
Retired Electrical Contractor
gobblerhuntr said:
2/0 copper or 4/0 al is a standard for us to hook up a 200 amp service and haven't have any problem in my 21 years at the POCO.

Well you are not the norm. No utility around here has used copper in 30 years or more and the utilities definitely undersize-- I would say 50% but a good 30% or more from the NEC
 

emf10

Member
Location
Southeast PA
As far as I know when dealing with service laterals here, for commercial the service is brought 18" onto the customers property. From there to the meter it is the customer's responsibility, and is installed according to the NEC. But I think in residential the PoCo normally brings it all the way to a meter on the wall, though in some cases the customer can own the laterals on their property. So I guess I would have to find out who owns these laterals, if it's the customer, then the #2 AL is undersized, if it's the PoCo then they might be fine.

*Edit: And one thing is for sure, around here the service drops from the PoCo are WAY undersized compared to the service entrance conductors.
 
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R Bob

Senior Member
Location
Chantilly, VA
iwire said:
I have no idea why you would say that?:confused:

Fill me in, because where I am those conductors on the line side of a service lateral meter would be power company conductors.

As far as the power company is concerned the size of the service the electrician chooses to install is pretty much irreverent.

What Larry is talking about is an illegal service upgrade. Typically performed by the homeowner or people who are unlicensed and can't or don't want to pull an electrical permit. I run across this frequently.

They replace the panel and, sometimes, the service entrance conductors.
They usually just reconnect the existing GEC w/o upgrading it to match the new service capacity.

No permit/inspection, POCO doesn't even know unless they pick up on the meter seal being broken.

You ought to see the look on their face when I explain it to them...priceless!

They didn't get what they expected, but they got what they paid for @1/2 the price of a legitimate upgrade! They just don't have a clue.
 

iwire

Moderator
Staff member
Location
Massachusetts
Bob I am still not following you, here from to the transformer to the meter are POCO conduits (service lateral) and they will not be changed.
 

iwire

Moderator
Staff member
Location
Massachusetts
Dennis Alwon said:
Well you are not the norm. No utility around here has used copper in 30 years or more and the utilities definitely undersize-- I would say 50% but a good 30% or more from the NEC

Dennis, they are not undersized, they are correctly sized for the application.

Trying to apply NEC ratings to power company work is both foolish and a waste of time. They are totally different. It like trying to apply Canadian laws to US soil. Not going to happen.
 

LarryFine

Master Electrician Electric Contractor Richmond VA
Location
Henrico County, VA
Occupation
Electrical Contractor
iwire said:
I have no idea why you would say that?:confused:

Fill me in, because where I am those conductors on the line side of a service lateral meter would be power company conductors.

As far as the power company is concerned the size of the service the electrician chooses to install is pretty much irreverent.
Okay, if we're using the term 'service lateral' the way the NEC does, then we're talking about an underground service, and the POCO owns it.

I was referring to overhead service drops, where the cable from the weatherhead to the meter should be as large as those from the meter to the panel.
 

iwire

Moderator
Staff member
Location
Massachusetts
LarryFine said:
I was referring to overhead service drops, where the cable from the weatherhead to the meter should be as large as those from the meter to the panel.

Gotcha, now it all makes sense to me. :smile:
 

Dennis Alwon

Moderator
Staff member
Location
Chapel Hill, NC
Occupation
Retired Electrical Contractor
iwire said:
Dennis, they are not undersized, they are correctly sized for the application.

Trying to apply NEC ratings to power company work is both foolish and a waste of time. They are totally different. It like trying to apply Canadian laws to US soil. Not going to happen.

My reply was to gobblerhuntr who works for the utilities and apparent they size there wires similar to the nec. My point was that most don't. I was not making a statement that they should. I don't care what size they use unless it causes issues at the house I wired. I have not had problems so....
 

iwire

Moderator
Staff member
Location
Massachusetts
Dennis Alwon said:
My reply was to gobblerhuntr who works for the utilities and apparent they size there wires similar to the nec. My point was that most don't. I was not making a statement that they should. I don't care what size they use unless it causes issues at the house I wired. I have not had problems so....

Don't take it wrong. :smile:

But (IMHO) it is incorrect to refer to the power company conductors as undersized.

I agree sometimes it does seem wrong, I have hooked some 800 amp services to surprisingly small service laterals. The power companies response when I asked. "What has changed?" I changed the service from 200 to 800 to meet todays rules but the actual building loads did not change. The 30 unit apartment buildings ran fine for probably 50 years on the old services and they will run just fine even with the new 800 amp meter stacks. The loads remains the same as they always where. :smile:

If we try to apply the NEC to the power company we would also say their transformers are under sized. But if tomorrow the power company had to meet the NEC all of our rates would be higher.

The long and short of it is they know what they are doing and are available 24/7 - 365 to fix anything that may break. :cool:
 
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