Meter & SEC

Home has a 200 amp main panel.

I question the meter and exterior SEC.

There are no markings on the exterior SEC.

The meter has an indication of SL 200 on the data plate.

I dont believe the meter and exterior SEC are rated for 200 amp and am calling an electrician to evaluate to make sure.

The interior copper seems adequate.

Also there is only the ground to the water line.

Shouldnt this be continuous to the street side of the meter?

No exterior ground rod.

Could an electrical guru shine some of there wisdom on reading the exterior meter data. Also on the water line/ground connections.

Since a new box was installed I dont know the year and it may or may not of been code and all that stuff.



Disregard the meter “rating.” My understanding is that this is actually a calibration rating (meters “rated” at 15 amps have been used on 200 amp service). It’s up to the utility if they want to change that out.

The SEC should be 3/0 CU. It’s difficult to determine from a photo if they are sized properly.

The grounding electrode can be the water line so long as it is at least 10 feet of continuous metal and should be on the house side of the water meter.

A recommendation for a secondary grounding electrode is prudent.

Without climbing up to check the wire at the service head or pulling the meter it will be hard to decide about the SE going there. You say the SE at the panel is “adequate” (2/0cu)
The drop is NESC regulated and probably #2.
There should be a supplimental ground but that is fairly new.

Jeff residential can use 2/0 cu or 4/0 al for the main feeder or SE to a 200a service. Table 310.15(B)(6)

I’ll buy that :smiley: This is definitely your field over mine. I was going off a general ampacity chart, not the SE chart.

Table 310.15(B)(6) can confuse folks because it only applies to the main feed (not sub-panels) but it recognizes the diversity you find in a dwelling. Most homes cruise at a small fraction of the panel rating, otherwise you would be seeing $3500 electric bills:roll:

I am one of those folks that can be easily confused.

Do you have any documentation on the exterior meters.

The whole theory of the round, square and rectangular exterior meters to help determine the service size seems to be confusing.

Thanks for the help.


Dave, Meters with round base are 60 amp rated. As for the overhead line - it’s exposed to the air and can be smaller than required for the mast or interior - utility has say over that and I have learned to not comment on the size of the overhead line. I would question the lack of a drip loop though.

Eric Barker
Barrington, IL

I would like to see verification of this statement.

My area has nothing other than round bases. As I stated in another thread, a recently inspected 600 amp service had a round base meter “rated” at 200 amps (CL200).

The information I am reading suggests that the meter base rating is more of a compatability issue rather than a limiting issue.

The round base is rated at 60 amps but remains compatable up to 100 amps.

The real issue with the meter base is the wire bending space. They make them bigger so you have more options for the entry and exit. I do see where a round base could be insufficient for a 2/0 if it did anything but straight in and out and even then it is probably not big enough. The utility should be the regulating agency if this was done legally since the meter base is their domain. I would just verify that the conductors are the right size as an HI.
I doubt the utility would do anything anyway if it was not called in as a trouble call.

Hi to all,

Interesting thread in the light of one of my recent QOD’s.
I have always believed that meter base shapes relate directly to there service rating (I have 3 seperate publications in front of me) that state that

  • Round meter bases Normaly cover upto 60 amps
  • Small square bases (about 1/2 larger than the meter) cover max 100 amps
  • Rectangular bases (and larger squares where the meter is off center) cover 200 amps
    Is this not the case? i see from Greg’s comments that this may not be true, here is the image I put together to explain this as a rule of thumb.

I’d like the opinion of the “house electrcians” on the validity of this.

Many thanks


This is what I got. . .

Hi Jeff,

Thanks, that is close to what I have.

It will be interesting to see other comments on this.



I go by what Jeff has. By looking at the wires you can tell what size they are. It is also written on the wire. If you don’t have a guage, go to the local supply house and get a small 6’ piece. After a while you can tell by looking. I would not alwyas go with the meter scenario.

Jeff you left out “in contact with earth”

Hey Guys,

My teaching method on this to tha apprentices are as follows…and in light of a lesser known factual method and based on my guest speakers at the local apprentice program from Virginia Power it is like this…

The original 60A meter cabs ( which in some cases are actually rated for 100A max ) were designed purly from a standpoint the meter was round so lets make the housing round.

As time went on the conductors became larger and more clearance space was needed to the next logical move was to a round port square design…but again some round may be rated for 100A…just part of progress.

Now as we move to the 200A service which also holds true for the 400A service since most cabs are 380A rated when dealing with that size and allows use in the 400A spectrum…I like that word so I had to use it today…:slight_smile:

As the SE conductors got larger…the enclosures also got larger and it simply from a practical since did not make any sense to make a larger "square " so to speak so the natural movement is to a rectangle.

To my best understanding their is no standardized rationing for this in the way of cab size or shape other than the obvious…so when looking at a round meter cab housing you simply cant say “oh its 60 Amps” because it is round…remember in many AHJ areas the POCO makes that choice which is why you see even smaller service drops than we would normally run…they work to their OWN beat…:slight_smile:

The round, square to rectangle method is solid for HI’s and will serve you fine…BUT be aware regardless of the cab housing…note the wire size, and inside enclosure ratings…means ALOT more than the meter can does…

just my advice…but again opinions are like…well you know what I mean…

I think Gerry’s idea for HI’s is fine…and builds a SOLID base for understanding…just keep in mind the obvious is not always the obvious…read the wires and enclosures carefully.

Nice post, Paul. :wink: