Residential service equipment configurations

[philn]

We are developing software to specify additions to a home's electrical system and want to make sure that 1) we use industry-standard terminology; 2) we do not make unjustified assumptions about what are the possible configurations. Are there residential service equipment configurations you've encountered in the field missing from the list below?

Name	Description
Meter-Main-Load Center	Utility meter, main breaker, and panelboard all in one enclosure.
Meter-Main and Main Lug Load Center	Utility meter and main breaker in one enclosure, main lug panelboard in separate enclosure.
Meter Base and Main Breaker Load Center	Utility meter in standalone enclosure, main breaker and panelboard in separate enclosure.
Meter Base, Main Breaker, and Main Lug Load Center	Utility meter in standalone enclosure, main breaker in separate standalone enclosure, and main lug panelboard in a third enclosure.
Meter Base and Split Busbar Load Center (Hot Bus)	Utility meter in standalone enclosure, main breaker and split busbar panelboard in separate enclosure. One side of the split busbar is hot.
Split Service Meter-Main-Load Center and Standalone Load Center	Utility meter, two main breakers and panelboard in one enclosure, with one of the main breakers feeding a panelboard in a separate enclosure.
Split Service Meter-Main with Dual Load Centers	Utility meter and two main breakers in one enclosure, with each main breaker feeding panelboards in separate enclosures.
Split Service Meter Base with Dual Load Centers	Utility meter in standalone enclosure, feeding panelboards in separate enclosures.

 

[augie47]

Two things to consider:
"Split Buss" panels are no longer allowed

The 2020-2023 requirement for "emergency disconnects" needs to be addressed.

 

[infinity]

Load center is not a phrase that I would use in any scenario.

 

[suemarkp]

There is a new requirement for residential emergency disconnects (required if the main breaker is not outside and accessible to firemen). These can be wired two ways -- not as service equipment, which doesn't affect much, but it is a bump in the wire, or it ends up being meter base -> Emergency Disconnect -> then the panel or panels which could be a main breaker type if the emergency disconnect was added to an existing service, or a main lug only load center. In the case where the emergency disconnect is service equipment, the neutral and ground must be separated in the load center whether it has a main breaker or not.

 

[philn]

Load center is not a phrase that I would use in any scenario.

Care to elaborate? What term would you use?

 

[philn]

The 2020-2023 requirement for "emergency disconnects" needs to be addressed.

There is a new requirement for residential emergency disconnects

Thanks for mentioning this. How do you typically meet this requirement? Add a standalone outdoor disconnect between the meter base and existing load center, upgrade to a outdoor meter-main, or some other way?

 

[suemarkp]

Yes. I'm not an electrician so I'm not sure how most do it. Probably install specific.

I did a service upgrade and did not want the main panel outside, so I would have added an disconnect outside if I had to do it (the requirement wasn't in place yet here so I didn't have to put it in). I kept my neutrals and grounds separated in the main panel in case I needed to add one in the future and it had to become the service disconnect.

 

[LarryFine]

I kept my neutrals and grounds separated in the main panel in case I needed to add one in the future and it had to become the service disconnect.

I always wire panels that way.