WHAT IS WRONG IN THIS PICTURE?

Status
Not open for further replies.
necGuru

necGuru

Member
Location
Jupiter
Occupation
GUBM'T 'LECTRIC INSPECTOR
There's probably a bunch here that have eyes to see. So here you go:


rr2.png


I encountered this situation on a large, apartment complex. The designer says I'm nuts.
He got the information from a "code class" and no - just to be clear - it wasn't Mike's. But supposedly these people are experts at teaching code.
I will post what code I think it is, after a few people respond.
Thanks.
 
Just to be clear -
two separate service laterals, each going to a separate service, placards compliant with 230.2(E) at each service disconnect location.
phase conductors have been omitted from the drawing, for clarity.
 
The extra bondiog jumper is allowed by Code, although likely superfluous in this case.
The presence of two neutral/ground bonds is not by itself an issue as long as we officially have two services rather than two feeders .The code specifies exact circumstances under which multiple services are allowed for a single building.

But I think that there is no way, with this configuration, to use a GFCI main breaker in either panel should that become necessary.
 
What seems compliant?
What is required?
Are you saying that the extra bonding jumper is required?
What code would require connecting two entirely different services together in this manner?
 
I would like to know the size of the wire going to the concrete encase electrode and the bonding jumper between the two services. In the pic it shows taped off of the wire going to the encased electrode.

Was both service installed at the same time. Is all rebar in the footer tied toghter.
 
Tulsa Electrician said:
I would like to know the size of the wire going to the concrete encase electrode and the bonding jumper between the two services. In the pic it shows taped off of the wire going to the encased electrode.

Was both service installed at the same time. Is all rebar in the footer tied toghter.
Click to expand...
The largest bonding jumper that would ever be required if it's required would be number four. If the bonding jumper is not required, what difference does the size make.

Generally other building codes would require that the rebar be tied together in some way, usually with wire ties or something similar.

This arrangement would make more sense to me if there was a firewall down the middle of the building so effectively it was two buildings.

Since there are supposedly two services, wouldn't there be 2 meters? I don't see in the sketch where the meters are.
 
2 services to a building are required to have a common GES, a Ufer is the simple solution. And yes there will be objectionable current.
 
tom baker said:
2 services to a building are required to have a common GES, a Ufer is the simple solution. And yes there will be objectionable current.
Click to expand...
But otherwise objectionable current in the building ground on the service side of the main disconnect (paralleling the service neutral) is generally ignored by the code.
 
The CEE that this installation has could have some resistance between the two services, but had this been structural metal or a water pipe electrode you sort of end up with same thing electrically.

As mentioned the two services, presumed to be permitted, would be required to connect to a common GES any way.

We often do the same thing when the single service is composed of separate disconnects in separate enclosures just not normally much distance between the enclosures.
 
For clarification, it is 2 entirely separate services at opposite ends of the building.

It is one building. It does not have a firewall "creating" two buildings.

Each service has it's own grounding electrode conductor (GEC) going down to the footing steel, as shown in the sketch.

And then in addition to that, this "jumper wire" or whatever one likes to call it, is attached from GEC to GEC, each of which attach to the common grounding electrode for the building.
 
necGuru said:
For clarification, it is 2 entirely separate services at opposite ends of the building.

It is one building. It does not have a firewall "creating" two buildings.

Each service has it's own grounding electrode conductor (GEC) going down to the footing steel, as shown in the sketch.

And then in addition to that, this "jumper wire" or whatever one likes to call it, is attached from GEC to GEC, each of which attach to the common grounding electrode for the building.
Click to expand...
might be somewhat redundant to use the jumper wire but really not prohibited either. Electrically you pretty much have same thing if you have any metallic components within the building that ultimately are bonded back to both electric services some examples might be piping, ductwork, steel framing, machinery, etc. and if not intentionally bonded are inadvertently bonded via EGC's run with branch circuits/feeders.
 
The original drawing did not show a tie to each other. Pretty sure it meant to. It showed two points of earthing which than would require a bonding jumpers. The words were there though. As far as size goes I was curious as what the drawing showed on there one line. They may for some reason want it sized per 250.102c as an additional jumper. For bonding other items. Water,fire,gas etc then the jumper size and termination point matters.
Sometimes what is left out help explain why. I also would say even with a larger bonding conductor for other items no need to run it to both. Once both services are tied to a common electrode it is one and I would do bonding using one proper sized conductor from one service main location.
As far as the drawing it self no need to have additional if the uffer is the common.
Another note on drawing the two services are feed from one transformer.
Another item to consider is the water used as an electrode and part of the electrode system.
This why I ask if all new and footing tied toghter. To be sure the concrete encased electrode can be used as a common. I have seen them break these type of building into two/ three pours and not tie them toghter.
 

Attachments

  • rr2~2.png
    rr2~2.png
    256.8 KB · Views: 10
All new, footing all tied together, ONE common grounding electrode for the ONE building, which is the concrete-encased electrode.
 
necGuru said:
All new, footing all tied together, ONE common grounding electrode for the ONE building, which is the concrete-encased electrode.
Click to expand...
Both services must connect to one common GES

I thin the real question is whether you can use the CEE itself as a bonding jumper in this situation or if that jumper in the image is actually required
 
necGuru said:
All new, footing all tied together, ONE common grounding electrode for the ONE building, which is the concrete-encased electrode.
Click to expand...
Based on that and the 2014 NEC
I would say your good unless there is admentents or the engineers says so and plans have been approved.
I have had to have plans amended removing rods when we used uffer. The AHJ said if stamped approved plans show it your doing it. Can't blame them for that.
I will follow as to see how this turns out. It's applicable to work around here. Please share all you can and let us know.
 
Status
Not open for further replies.
Top