125A from pole to 200A Panel

[Jan Lombard]

Hi,
I have seen this before here - a 125 A electric supply cables connecting up to a 200A cables at the mast head and 200A panel.
What is the argument why this should not be acceptable.

---and what are the arguments against the opposite?. i.e. 200A supply going into a, say, 125A panel supply wires and panel. (afterall the panel is designed to not draw more than 125A in this case?)

[cbuell]

The cables from the street are in "free air" and rated differently; on top of that, the utility company can do what ever they want

[wsiegel]

There is nothing wrong with the way that is wired.

[jbreazeale]

As was stated above, the utility company can do whatever they want. For our purposes, the amp rating reported should be the lesser of:

The main overcurrent device, the ampacity of the service wires through the masthead, or the rating of the meter. In other words, a 200 amp rated panel with a 100 amp overcurrent device is rated as a 100 amp service. If by some chance it has all been "updated" below an old 60 amp meter base, it's a 60 amp, and should definitely be called out. Quick.

[Jan Lombard]

the problem is not the 125A supply but the 200A the house is capable of drawing.

The 125A from utility company is OK, they seem to do what they want and that is not the problem - however the home owner upgraded to a 200A panel and masthead because they splitleveled the house and wanted more circuits - so now you have 125A max supply with possible 200A max that may be drawn
In fact the house - having now a family living upstairs and another downstairs, have a shortage of circuits and a multitude of extension cords -
so what happens if more is drawn (200A) than is supplied (125A from the road)

[tdietrich1]

Darn this is hard to convey.

One of the NEC's major goals is to prevent fires. This is why the NEC is actually chapter 70 in a larger NFPA manual. Here it is. The NEC doesn't apply to utility cables, they don't run inside this house, so no house fire. They have their own industry specific codes. OK?

Ok, lets say this isn't enough. For a service to be upgraded the new cables, have to be snipped. Thus requiring the utility to be called. At this point they ask questions, allow work to be done (issue a job #), etc. They got the information. Temp splice are put in by the home electrician, and then the utility comes out and puts in perm splices. They are made aware, and even have a line person check out the cables. Since it's their equipment, they have a vested interest in keeping it safe. <information per our local utlity>

tom

P.S. Sorry, typing out this seemed challenging; so I didn't flame, just wrote out what's what. Maybe a online teacher like Paul can better explain why.

[Greg Fretwell]

Why do you say this is 125a?
A 200a service is usually supplied with a 2 ga aluminum triplex drop.
You just have to believe the utility knows what they are doing.

[cwillick1]

is this going from their own pole to their house or from the hydros pole to their house

[Jan Lombard]

Originally Posted by cwillick1

is this going from their own pole to their house or from the hydros pole to their house

From Hydro pole to house.
125A size supply from hydro pole to 200A at mast wires and Panel with main Panel breaker of 200A
--- This is old and anything seemed OK years ago - we speak of possible problems today

[Speedy Petey]

It's not that hard to convey.
THE WIRE FROM THE (poco) POLE TO THE HOUSE IS INSIGNIFICANT.

You keep referring to 125 amps. WHERE DID YOU GET THIS NUMBER?????
PLEASE show me a reference where it states this wire is a 125 amp feed.
Do you even know exactly what size and insulation type it is?

The POCO sizes this wire as they see fit. It is a 200 amp drop if they say it is.
I know this is an extremely hard concept to swallow since we are all so code oriented.

You know how often the POCO replaces the drop when I do an upgrade to 200 amps? RARELY.

[Marc D. Shunk]

The utility aerial drop is sized to NESC ampacities, and not to NEC ampacities. There's a HUGE difference in how they rate their conductors. Under NESC rules, #2 AL is good for 200 amp, and #1/0 AL is good for 320. They also size their conductors to your load, and not your apparent service size. That is to say, if they have knowledge of the load history, they are permitted to size their drop in accordance with that data, without regard to your service size. You'll sometimes see 3-strand #6 solid serving 200 amp NEC service equipment, and it's "legal".

[Paul W. Abernathy]

I think what is important here is regardless of the NESC standards...at the point they CONNECT to my SE Cable at the mast head or within the lat. meter enclosure the NEC does prevail...........and NEC conditions do apply !

Code or not.....#2 AL is not acceptacle for SE conductors for a 200A service....just want the guys to understand that....

Understand you can't dictate the Service Drop size...thats POCO's determination...but once it makes a connection at the mast head or in the Lat. enclosure.....it then must comply with 310.15(B)(6) or 310.16 per the NEC.

[Scott Schultz]

How about copper SEC labeled 1/0 AWG connected to a 200 amp main breaker. Today was the second time I've seen this.