Size of GEC

[peter d]

No "oops" there because generally the conductors on the load side of the meter are the larger conductors. :smile:

That is true. I think it's a rare case when/if they will exceed the line side conductors.

 

[infinity]

Note 1 of T.250.66 requires the combined size of the two 4/0s.

I will go on to point out in this particular case the 350s do not exist to the NEC.

Agreed. I was getting hung up on what Pierre had said in post #4 about running one conductor back and sizing it as such. Since the conductors feeding the meter are not service entrance conductors (in this case) then they're irrelevant.

 

[Pierre C Belarge]

Agreed. I was getting hung up on what Pierre had said in post #4 about running one conductor back and sizing it as such. Since the conductors feeding the meter are not service entrance conductors (in this case) then they're irrelevant.

My post dealt with the panels, not the meters.

Service entrance conductors start at the load end of the service drop or lateral.

For the service lateral, that may be the meterpan, depending on where the service lateral is installed from (such as a property box).
For the service drop, this will be the Service Point.

 

[iwire]

That is true. I think it's a rare case when/if they will exceed the line side conductors.

In almost any multiple service disconnect installation the combined total size of the smaller conductors will be larger then the large conductors. I also suggest that you forget about the 'line side' 'load side' and the meter(s) (Did that make sense)

The meter could be replaced with a splice can and the code rules would remain unchanged.

 

[kec]

thanks gentleman for a great discussion on this thread.
I think i found my ans. Note 1 table 250.66 Also Exhibit 250.28 Pg. 214 of the NECH shows a example.

 

[infinity]

thanks gentleman for a great discussion on this thread.
I think i found my ans. Note 1 table 250.66 Also Exhibit 250.28 Pg. 214 of the NECH shows a example.

What year NECH are you referencing?

 

[peter d]

In almost any multiple service disconnect installation the combined total size of the smaller conductors will be larger then the large conductors. I also suggest that you forget about the 'line side' 'load side' and the meter(s) (Did that make sense)

Yes, I'm aware of that now. As for the "line" and "load" it was just a term of convenience to distinguish between a riser and what's coming out of the bottom like in the 6-gang service. I normally wouldn't use that terminology but for this discussion it just makes sense.

 

[shortcircuit2]

To answer the original question from KEC about the size of the GEC required for the service he describes with multiple disconnecting means...

I would look to section 250.64(D) of the 2008 NEC that is being enforced here in Massachusetts which requires us to select a method of installation of the GEC as described in section 250.64(D)(1), (D)(2) or (D)(3)

(D)(1) allows taps to each switch from a common GEC sized based on the size of the largest service-entrance conductor(s)

(D)(2) allows me to run seperate GEC from each switch to an electrode based on the size of the service-entrance conductor(s) feeding the each switch

(D)(3) allows the GEC to be connected at common location in an accessible enclosure on the supply side of the dissconnecting means sized according to the service-entrance conductor(s) at the common location

shortcircuit2

 

[shortcircuit2]

The grounding electrode is a metal water pipe in the original post...so this would be required to be bonded with a #2 copper conductor per 250 104(A)(1)

 

[romeo]

Size of Gec

Size of Gec

The grounding electrode is a metal water pipe in the original post...so this would be required to be bonded with a #2 copper conductor per 250 104(A)(1)[/QUOT

If #2 aluminum is used for Bobs 6 meter service it would also require #2 copper.( I think )

 

[benaround]

Might as well toss this in here also, 4/0Al. is only good for 150a if run into the building and

you are on the 2008 NEC.

 

[HotConductor]

Service conductors supplying a single service disconnect are required to have an ampacity at least as high as the overcurrent device. See 230.90(A) {You could actually apply the rules of 240.4(B) as well, see 230.90(A) Exception 2}


Service conductors supplying multiple service disconnects are required to have an ampacity only as high as the calculated load. See 230.90(A) Exception 3.

:smile:

Doesn't this contradict 310.15(B)(6)?

 

[HotConductor]

Confused

Confused

Okay- this whole thread is all over the place and I'm new at this. Are you(anyone) saying that overload protection is required for service entrance conductors? If I look at Figure 230.1 no overload protection is required until the first point of disconnect or immediately adjacent to(230.91), correct?