Run EGC for 400 feet?

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spectrum24

Member
Location
Tampa, FL
I often am asked for simple designs to run service from a power company service point to a location 200-600 feet away. Is it typical to run an EGC along with the service wire, or is it permissible to install a ground rod at each end.

If i'm using stepup/down transformers, I always use a separately derived ground but i'm not sure when running 240/120 for these extended distances.

Thanks
 

Dennis Alwon

Moderator
Staff member
Location
Chapel Hill, NC
Occupation
Retired Electrical Contractor
If these are service conductors and no disconnect at the pole then you do not run an egc. May I ask why you are designing the electrical system rather than an engineer.
 

kwired

Electron manager
Location
NE Nebraska
I often am asked for simple designs to run service from a power company service point to a location 200-600 feet away. Is it typical to run an EGC along with the service wire, or is it permissible to install a ground rod at each end.

If i'm using stepup/down transformers, I always use a separately derived ground but i'm not sure when running 240/120 for these extended distances.

Thanks

Don't get the ground rods mixed in with purpose of running a grounding conductor. Do you need ground rods at each end? - Good possibility you do, but it has nothing to do with whether or not you ran an equipment grounding conductor. You never substitute a ground rod for an EGC. On service equipment the grounded service conductor is bonded to all metal enclosures making an additional EGC redundant and actually puts it in parallel with the grounded conductor.
 

spectrum24

Member
Location
Tampa, FL
If these are service conductors and no disconnect at the pole then you do not run an egc. May I ask why you are designing the electrical system rather than an engineer.

Well, the 2nd part of that is a good question and a long story. As to the first part, it is a service conductor that runs to a meter pedestal, and there is a disconnect there. From there, it runs some distance to an equipment cabinet, where there is generally another disconnect to allow workers to disconnect before working on the cabinet. The "Engineers" seem to have different concepts on if to run an EGC or not. Some say yes, some say no. Poking around here seems to indicate you can do either, if yes then don't bond it to the neutral at the far end, if no, then bond the neutral and ground at the equipment end panel. I'm just trying to come up with a rule of thumb.

thanks
 

Dennis Alwon

Moderator
Staff member
Location
Chapel Hill, NC
Occupation
Retired Electrical Contractor
If there is a disconnect at the pole then an egc is required but that would depend if you are on the 2008 or higher NEC. In 2005 it was allowed without the egc in certain situations. BTW-- these are not service conductors if they go thru a disconnect. The wire is a feeder.
 

kwired

Electron manager
Location
NE Nebraska
If there is a disconnect at the pole then an egc is required but that would depend if you are on the 2008 or higher NEC. In 2005 it was allowed without the egc in certain situations. BTW-- these are not service conductors if they go thru a disconnect. The wire is a feeder.

I will add the disconnect must contain overcurrent device, otherwise they are still service conductors.
 

david luchini

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Staff member
Location
Connecticut
Occupation
Engineer
I will add the disconnect must contain overcurrent device, otherwise they are still service conductors.

This doesn't sound right to me. The service conductors are the conductors from the service point to the "service disconnecting means." The service conductors don't extend past the service disconnecting means. If there is no OCPD in (or adjacent to) the disconnect, then you have a violation of 230.91.
 

Smart $

Esteemed Member
Location
Ohio
This doesn't sound right to me. The service conductors are the conductors from the service point to the "service disconnecting means." The service conductors don't extend past the service disconnecting means. If there is no OCPD in (or adjacent to) the disconnect, then you have a violation of 230.91.
Could be a meter disconnect switch and be compliant - 230.82(3)
 

kwired

Electron manager
Location
NE Nebraska
This doesn't sound right to me. The service conductors are the conductors from the service point to the "service disconnecting means." The service conductors don't extend past the service disconnecting means. If there is no OCPD in (or adjacent to) the disconnect, then you have a violation of 230.91.

If there is no OCPD then it is not a service disconnecting means. It is just a switch located in the service conductors.
230.82(3) and 547.9(A) are the only places I see that allow a disconnect on the supply side of the service disconnect. There could be a few other places.


230.91 tells us the service overcurrent protection device must be part of or adjacent to the service disconnect, so in order for it to be a service disconnect there must be associated overcurrent protection, otherwise the load side conductors are still considered service conductors.
 

spectrum24

Member
Location
Tampa, FL
We would typically have a disconnect and OCPD at the meter pedestal. Then 20- to several hundred feet later, we would have another disconnect with an OCPD. Question is, should the EGC be run all the way though, and if so should it be bonded to neutral at both ends.

If EGC is not run, then I believe we are to only bond at the first disconnect, but as we have a second disconnect with OCPD, I'm not sure.
 

david luchini

Moderator
Staff member
Location
Connecticut
Occupation
Engineer
230.91 tells us the service overcurrent protection device must be part of or adjacent to the service disconnect, so in order for it to be a service disconnect there must be associated overcurrent protection, otherwise the load side conductors are still considered service conductors.

Yes, that is what I pointed out. You would have a violation of 230.91 if you do not have a OCPD in or adjacent to the service disconnecting means. But no, you cannot have a disconnect before the service disconnect (other than the meter disconnect in 230.82(3), but there was no mention of a meter disconnect in the OP). That would be a violation of 230.82.

The definition of service conductors is "the conductors from the service point to the service disconnecting means." 230.82 does not permit an additional disconnect in the service conductors on the supply side of the service disconnect (again except as in 230.82(3)). Therefore the disconnect is the service disconnecting means, and the conductors on the load side of the disconnect are no longer service conductors.

If there is no OCPD at the service disconnect, then there is a violation of 230.91. If there is a disconnect with an OCPD on the load side of the first disconnect which is considered to be the service disconnecting means, the the first disconnect is in violation of 230.82.
 

kwired

Electron manager
Location
NE Nebraska
Yes, that is what I pointed out. You would have a violation of 230.91 if you do not have a OCPD in or adjacent to the service disconnecting means. But no, you cannot have a disconnect before the service disconnect (other than the meter disconnect in 230.82(3), but there was no mention of a meter disconnect in the OP). That would be a violation of 230.82.

The definition of service conductors is "the conductors from the service point to the service disconnecting means." 230.82 does not permit an additional disconnect in the service conductors on the supply side of the service disconnect (again except as in 230.82(3)). Therefore the disconnect is the service disconnecting means, and the conductors on the load side of the disconnect are no longer service conductors.

If there is no OCPD at the service disconnect, then there is a violation of 230.91. If there is a disconnect with an OCPD on the load side of the first disconnect which is considered to be the service disconnecting means, the the first disconnect is in violation of 230.82.

What about the site isolating device I mentioned in 547.9(A)? I run into that one all the time.

Most of the time that switch is provided by the POCO here. It may or may not have overcurrent protection in it. If it needs replaced usually the POCO is the one to do so. They will not necessarily replace with the same thing that was there.

For that reason around here we are not allowed to consider a disconnect provided by POCO to serve as a service disconnect even if it otherwise qualifies as one because they can change it to one that does not qualify as one whenever they wish. I do understand that this makes it somewhat of a local rule, but at same time you need to consider 90.2(B)(5).
 

spectrum24

Member
Location
Tampa, FL
Art 100 defintion



It is still a structure by NEC definitions.

Fine.. that makes it easier. The question is still unclear.. if I have a seperate OCPD at the cabinet, wouldnt it make sense to create a new ground system and bond it there? That way if anything shorts to metal which is grounded, that breaker will trip, rather than having to rely on a breaker 400 feet back?
 

Smart $

Esteemed Member
Location
Ohio
Fine.. that makes it easier. The question is still unclear.. if I have a seperate OCPD at the cabinet, wouldnt it make sense to create a new ground system and bond it there? That way if anything shorts to metal which is grounded, that breaker will trip, rather than having to rely on a breaker 400 feet back?
Separate structue requires a GES, same as service "structure". Difference is GES is bonded to EGC, but isolated from grounded circuit conductor.
 

Dennis Alwon

Moderator
Staff member
Location
Chapel Hill, NC
Occupation
Retired Electrical Contractor
Art 100 defintion



It is still a structure by NEC definitions.

I just saw a proposal to the 2014 that asks that equipment -- such as generators -- should not be included in the term structure.

_______________________________________________________________________________________________
William Benard, Gemini Electric Inc.
Add new text to read as follows:
Recommendation: Structure--That which is built or constructed for other than listed or identified freestanding electrical equipment.

Substantiation: This proposal attempts to address different interpretations of the term structure especially when a disconnecting means is required at a structure in Section 225.32 and in at least one case by clarifying that a disconnecting means is not required at a standalone transfer switch or other approved freestanding transfer equipment where the conductors are already protected by equipment ahead at the source as in the case of a generator with a built in feeder disconnect.

Although not all in the industry would consider standalone transfer equipment as a "structure," it is hard to convince those that do that such equipment does not fit the existing literal wording in the definition of the term in Article 100. The addition of the wording in the new definition would clarify for more consistent interpretation and determination as to the intention of the protection requirements determined for a "structure." If freestanding electrical equipment is intended to qualify as a "structure" then the listing evaluation should consider construction and structural integrity as a component of the package listing mark, and they do not at this time.
 
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