Equipmnet ground location

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Ken9876

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I have a question on the location of the EGC, is there a spot at the service where it should or should not originate from? I have this job where a service switch was installed, but they used a fused disconnect for the switch. The neutral is not bonded to that switch which I see as one big problem. Then the conductors feed into the meter pan where the EGC is bonded to the service neutral, From the meter pan the 277/480 volt feed runs to the building about 300? away, into a main breaker. The neutral and EGC are separate at that location, which I feel is correct because the OCPD for the service was at the meter pan so the conductors running up the building become feeders and the neutral and EGC should be separate. But the EGC coming from the meter pan seems odd.
 
A service GES can be bonded at any point from load end of service drop/lateral
to and including the service disconnect. 250.24(A)(1)
 
Smart $ said:
A service GES can be bonded at any point from load end of service drop/lateral
to and including the service disconnect. 250.24(A)(1)
Click to expand...

The equipment gounding conductor starts at the meter pan, where the GEC also is located. My question is I've never seen the EGC start at a meter pan.
 
It may have started there to keep the conduit (assumption that there is metal conduit) from becoming a parallel path for neutral current if the grounded conductor was re-grounded at the OCPD enclosure 300ft from the meter enclosure. No problem starting at the meter.

Is there metal conduit bonding the meter enclosure and the fused switch disconnect enclosure ?
 
Ken9876 said:
It's pvc, between the disconnect and the meter pan
Click to expand...

I agree with your accessement that this is one big problem. Problem=Hazard. If a phase comes into contact with the disconnect switch enclosure it will energize the enclosure, no fuses will blow, no breaker will trip. Just 277 volts looking for a path back to the transformer.
 
There is a path, but it's too small they bonded the service switch, which really is the main with a #6 that is bonded in the meter pan
 
Ken9876 said:
There is a path, but it's too small they bonded the service switch, which really is the main with a #6 that is bonded in the meter pan
Click to expand...
Let's backtrack here for some clarification...

Is the meter pan before (on the line side of) or after (on the load side of) the service disconnecting means?

Your original statement...
Ken9876 said:
The neutral is not bonded to that switch which I see as one big problem. Then the conductors feed into the meter pan where the EGC is bonded to the service neutral, From the meter pan the 277/480 volt feed runs to the building about 300? away, into a main breaker.
Click to expand...
...leads me to believe the SDM is ahead of the meter pan. Yet the more important question is on which side of the SDM is the GEC/EGC/(MBJ)/Neutral connection(s)???

You state the neutral is not bonded to the switch (enclosure). Does this also mean the is no grounding conductor bonded to the switch enclosure?
 
Smart $ said:
Let's backtrack here for some clarification...

Is the meter pan before (on the line side of) or after (on the load side of) the service disconnecting means?

Your original statement...
​
...leads me to believe the SDM is ahead of the meter pan. Yet the more important question is on which side of the SDM is the GEC/EGC/(MBJ)/Neutral connection(s)???

You state the neutral is not bonded to the switch (enclosure). Does this also mean the is no grounding conductor bonded to the switch enclosure?
Click to expand...

The meter pan is on the load side of the disconnected which is fused at 200 amps. All the connections GEC,EGC, MBJ are all on the load side of the disconnect in the meter pan, they ran a #6 bonding jumper into the disconnect and bonded it with that.
 
Ken9876 said:
The meter pan is on the load side of the disconnected which is fused at 200 amps. All the connections GEC,EGC, MBJ are all on the load side of the disconnect in the meter pan, they ran a #6 bonding jumper into the disconnect and bonded it with that.
Click to expand...
Then the installation is in violation of various parts of 250.24.

Realistically, it is not unusual for bonding to take place in the meter pan. However, that is only true when the meter pan is on the line side of the SDM. Yet while bonding downstream of the SDM is a violation, how much less safe is it? The answer is based in how much difference is attributable to the grounded conductor between the SDM and meter pan. The worst aspect of this non-compliant installation is the #6 bonding jumper. It should be at least #2 copper.
 
SG-1 said:
It may have started there to keep the conduit (assumption that there is metal conduit) from becoming a parallel path for neutral current if the grounded conductor was re-grounded at the OCPD enclosure 300ft from the meter enclosure. No problem starting at the meter.
Click to expand...
Agreed but there are tons of parallel paths between the meter socket and the the first OCPD out there in the field with no violation when metallic conduit is used.
 
SG-1 said:
...

Smart $, could they be thinking the Fused Switch is for meter isolation ? Otherwise why is it there ?
Click to expand...
They could be thinking that... but such switches to my knowledge are not fused. I think the POCO would have some input on that, too. They generally do not care for any location ahead of the meter that can easily be tapped ;)
 
A/A Fuel GTX said:
Agreed but there are tons of parallel paths between the meter socket and the the first OCPD out there in the field with no violation when metallic conduit is used.
Click to expand...
Yep. We accept them as unavoidable and, thus, call them unimportant.

A ground is a ground is a gound ahead of the main. It's also a CCC. ;)
 
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