Service Entrance Grounding

[Moistness]

I have a question that every time I think I know the answer, I read or watch a video that makes me doubt myself.
On a service, residential or industrial, the conductors that pass through the meter now need to enter a "disconnect" outside of the home or building.

My question is, the bounding jumper that bounds the neutral to ground, does this happen in the disconnect outside of the home and thus the neutral and ground will need to be separated from that point on or do you also tie the neutral and ground together say in a lighting panel that this disconnect is feeding, that before this new code came down, was your service disconnect and where the bonding jumper bonded the neutral to ground?

Another question, does this "disconnect" need to have over current protection, or can it just be non-fused?
If true, do you even bond the neutral in the disconnect or do you keep them separate until you land on the first over current protected device?

If you can point me to the NEC for the answer it would be much appreciated.

Thank you.

 

[infinity]

All metal parts and enclosures upstream of the service disconnect and bonded directly to the neutral. Where your service disconnect is will determine when the EGC's and neutrals require separation.

 

[augie47]

To some degree the answers vary a but dependent on Code cycle. If PA is still on the 2017 the outside disconnect may not even be required.
Under later Code cycles, if the outside disconnect is an "emergency disconnect" the neutrals and equipment grounding would take place at the service equipment. If the outside disconnect is considered a "service disconnect" then separation would be required at any panel beyond that.

 

[Moistness]

So, maybe I'm not clear in my questions so I drew a simplified sketch.
I have both a non-fused and fused disconnect in line with an incoming service.



My main question is, what do you do with the bonding jumpers? Do they get installed as shown in the sketch or something else?
Is there a difference if the disconnect is fused or non-fused?

Thank you.

 

[infinity]

The conductor that you have labeled "ground" in the non-fused diagram (EM disconnect) must be removed as it is in parallel with the neutral. In the fused disconnect if that is the service disconnect then the neutral/EGC bonding jumper in the panel must be removed.

 

[Moistness]

The conductor that you have labeled "ground" in the non-fused diagram (EM disconnect) must be removed as it is in parallel with the neutral. In the fused disconnect if that is the service disconnect then the neutral/EGC bonding jumper in the panel must be removed.

Regarding the non-fused disconnect, does the bonding jumper get installed in both the disc. sw. and panel or one or the other?

Does the metal enclosure of the non-fused disc. still require grounded?
If so, does the ground wire terminate to a ground rod/ground grid?

Regarding the fused disconnect, if it is not the service disconnect, does it get treated like the non-fused disc. sw.?

In my example, must the fused disconnect be the service disconnect or can you allow the main of the panel to be the service disconnect?

 

[augie47]

Regarding the non-fused disconnect, does the bonding jumper get installed in both the disc. sw. and panel or one or the other?
Bonding jump;er gets installed in both
Does the metal enclosure of the non-fused disc. still require grounded? The bonding jumper provides the only ground needed.

If so, does the ground wire terminate to a ground rod/ground grid?
You can elect to connect your grounding electrodes here
Regarding the fused disconnect, if it is not the service disconnect, does it get treated like the non-fused disc. sw.?
Yes
In my example, must the fused disconnect be the service disconnect or can you allow the main of the panel to be the service disconnect? Either

 

[infinity]

Does the metal enclosure of the non-fused disc. still require grounded?
If so, does the ground wire terminate to a ground rod/ground grid?

There is no "ground wire" (proper term Equipment Grounding Conductor) because the disconnect is upstream from the service disconnect which is in the panel. A conductor to a grounding electrode would most likely be a Grounding Electrode Conductor.

 

[Moistness]

Thank you both. It's appreciated.
Is there an NEC article you can reference that explains my illustration and your corrections?

 

[augie47]

Thank you both. It's appreciated.
Is there an NEC article you can reference that explains my illustration and your corrections?

The grounding electrode conductor connection is covered by 250.24(A)(1)
Use of the grounded conductor for grounding supply side equipment 250.142(A) & 250.24(B)

 

[infinity]

Also the bonding jumper that is parallel to the neutral with the non-fused disconnect is in 250.6.

 

[jaggedben]

I think some clarifications are needed.

In your diagram with the fused disconnect, remove the neutral-to-ground bond and the grounding electrode in the panelboard. Then you have what has been considered a 'normal' service for a hundred years, with a service disconnect after the meter, and neutral and ground separated on the load side of the service disconnect. (The outside vs. inside part has not mattered until recently and only for one and two family dwellings. Also note the NEC doesn't care where the meter is, but utilities typically do.) Burn that revised image into your head as the 'normal' configuration before you go start learning about exceptions such as Emergency Disconnects. Generally the first disconnect coming from the utility is the service disconnect.

The non-fused disconnect example would only be allowed if labeled as an Emergency Disconnect for a one or two family dwelling since 2020 in some parts of the country.
This has only been allowed in the 2020 and 2023 NECs and may go away again in 2026. Otherwise it would be considered a service disconnect but would not comply with the requirements for overcurrent protection at the service disconnect, meaning a fused disconnect or circuit breaker is required.

 

[electrofelon]

Thank you both. It's appreciated.
Is there an NEC article you can reference that explains my illustration and your corrections?

For the emergency disconnect parts see 230.85:

230.85 Emergency Disconnects.

The 2020 NEC requires an exterior emergency disconnect for one- and two-family dwelling units.

www.electricallicenserenewal.com

 

[tom baker]

I think some clarifications are needed.

In your diagram with the fused disconnect, remove the neutral-to-ground bond and the grounding electrode in the panelboard. Then you have what has been considered a 'normal' service for a hundred years, with a service disconnect after the meter, and neutral and ground separated on the load side of the service disconnect. (The outside vs. inside part has not mattered until recently and only for one and two family dwellings. Also note the NEC doesn't care where the meter is, but utilities typically do.) Burn that revised image into your head as the 'normal' configuration before you go start learning about exceptions such as Emergency Disconnects. Generally the first disconnect coming from the utility is the service disconnect.

The non-fused disconnect example would only be allowed if labeled as an Emergency Disconnect for a one or two family dwelling since 2020 in some parts of the country.
This has only been allowed in the 2020 and 2023 NECs and may go away again in 2026. Otherwise it would be considered a service disconnect but would not comply with the requirements for overcurrent protection at the service disconnect, meaning a fused disconnect or circuit breaker is required.

Good explanation