Service Grounding

[anbm]

See attached image, can we have the service grounding (bond to ground rod, metallic water pipe, ufer, etc.) at panel DPA but not at the 400A fused disconnect after utility transformer?

 

[Dennis Alwon]

See attached image, can we have the service grounding (bond to ground rod, metallic water pipe, ufer, etc.) at panel DPA but not at the 400A fused disconnect after utility transformer?

Yes, assuming that the 400 amp fused disconnect is not at the building.

 

[infinity]

Is that 200' between the service disconnect at the transformer and the DPA underground? If so then you'll need a GES at each location.

 

[Dennis Alwon]

Is that 200' between the service disconnect at the transformer and the DPA underground? If so then you'll need a GES at each location.

That is correct. I assumed there would be a grounding electrode system at the remote disconnect. I need to learn to read the question

 

[Dennis Alwon]

I guess I was trying to say you don't need to run the water pipe grounding electrode conductor out to the disconnect.

 

[anbm]

Yes, assuming that the 400 amp fused disconnect is not at the building.

Yea, 400A fused disc by the xfmr, main panel us 200 feet away at the building and underground feeder. Thought the code only allows GES at first disconnect after service transformer?

 

[infinity]

Yea, 400A fused disc by the xfmr, main panel us 200 feet away at the building and underground feeder. Thought the code only allows GES at first disconnect after service transformer?

No a GES is required at each separate structure. Since you have a feeder to the building the GEC would terminate at the EGC bus not on the neutral bus. Take look at 250.32.

 

[anbm]

Yea, 400A fused disc by the xfmr, main panel is 200 feet away at the building and underground feeder. Thought the code only allows GES at first disconnect after service transformer?

 

[anbm]

What you said … GES is required at both locations but ground and neutral bond can only be established at the 400A fused disc, correct?

 

[infinity]

What you said … GES is required at both locations but ground and neutral bond can only be established at the 400A fused disc, correct?

Yes. The service conductors end at the 400 amp service disconnect so anything down stream of that cannot have the neutral and EGC connected together therefore you would connect the GEC at the building to the EGC bus. The neutral bus would not be bonded at the building.

 

[anbm]

Got it. TY

 

[Dennis Alwon]

Got it. TY

I assume you know that you will need an egc from the remote disco to the MDP

 

[david]

Yea, 400A fused disc by the xfmr, main panel us 200 feet away at the building and underground feeder. Thought the code only allows GES at first disconnect after service transformer?

Just curious does your utility require the disconnect the one out near what you identified as a utility transformer.

Also curious as to what voltage the 400 amp service is.

Also curious as to the location of the meter

: here the utility would only run there conductors 100 ft onto the customer's premises if it was a service drop.

: the utility here would not have that same restriction on a utility lateral.

Also for certain voltages for line voltage metering the utility will require a site isolation switch that is not a service disconnect.

I ask because if something like that is going on it might change some of the answers given.

Over the years I have learned to answer questions that I receive over the phone with a prefix.

If I am understanding what you are seeing than this is your answer

 

[anbm]

Just curious does your utility require the disconnect the one out near what you identified as a utility transformer.

Also curious as to what voltage the 400 amp service is.

Also curious as to the location of the meter

: here the utility would only run there conductors 100 ft onto the customer's premises if it was a service drop.

: the utility here would not have that same restriction on a utility lateral.

Also for certain voltages for line voltage metering the utility will require a site isolation switch that is not a service disconnect.

I ask because if something like that is going on it might change some of the answers given.

Over the years I have learned to answer questions that I receive over the phone with a prefix.

If I am understanding what you are seeing than this is your answer

480V/277V service, yes the client needs a main service fused disconnect within sight of the poco xfmr secondary or the underground service feeder needs to be concrete encased.

 

[david]

480V/277V service, yes the client needs a main service fused disconnect within sight of the poco xfmr secondary or the underground service feeder needs to be concrete encased.

Kind of the reason I ask the questions.

Here for a 480/277 volt service up to 400 amps you would use line voltage metering.

The sldisconnect you show near the transformer in this area would be a site isolation disconnect on the line side of the service.
Here the utility would prefer the isolation swith to be un fused up to A 10k AIC rating.
The utility here will however except a fused disconnect as a isolation switch.

If that fused disconnect is in fact a isolation switch required by your utility on the line side of your service.
The answers you received in this thread will change

 

[david]

480V/277V service, yes the client needs a main service fused disconnect within sight of the poco xfmr secondary

i think that needs clarification. Is it a service disconnect or not

or the underground service feeder needs to be concrete encased.

That sounds like a utility regulation. If so than that portion would be part of the utility lateral.

Utility regulations would not apply to anything on the load side of a service disconnect

 

[david]

Here the isolation switch would be required to have a grounding electrode by utility regulations.

The big difference, is a equipment ground required from the fuse disconnect to the building or not.
Is the main bonding jumper required at the fused disconnect or at the building

 

[david]

Here the isolation switch would be required to have a grounding electrode by utility regulations.

The big difference, is a equipment ground required from the fuse disconnect to the building or not.
Is the main bonding jumper

I should have said is the main bonding jumper required by the NEC at the fused disconnect or at the building

required at the fused disconnect or at the building

the NEC requires it at the service location. The utility regulations here would require a neutral bonded grounding electrode at the isolation switch. We wouldn't call what the utility requires a main bonding jumper.

If the fuse disconnect is on the line side of the service you could end up having the grounded conductor bonded at both locations with no equipment ground run from the fusible disconnect to the building

 

[mtnelect]

Too many ground rods !

When I was doing traffic signal work for the County of Los Angeles, we started converting our controllers from electromechanical to digital. We were installing "170 Controllers" which were all solid state. Our electrical service started on a utility pole and went underground to the controller where we installed a second ground rod. After installing several cabinets, we started getting calls that the intersections were going on "Flash". I discovered that there was a difference in potential between the two ground rods. So, I disconnected the second ground rod at the controller cabinet and pulled a grounding conductor back to the service, and that corrected the problems.