This is how I understand a res service is done. If the MBJ in the main panel is removed, I’d have to isolate grounds and neutrals correct?

[Phillip Land]

Your service disconnect is outside in the meter main. The panel inside is a subpanel and requires ser which is 4 wires. You need a neutral, 2 hots and an equipment grounding conductor. No bonding in the second panel-- everything is done outside at the meter main

I thought the entire point of moving the main breaker from the inside panel to the outside was safety.
1. the means of disconnecting all power from a building in an emergency (such as a fire) can be reached more quickly
2. With a main breaker outside, there is now overcurrent protection and short circuit protection on the conductors passing through the structure of the building where there wasn't before

With that being said, I understood that the "em disco" was a way to add a disconnecting means to a structure like a detached garage or a pool house if the main breaker (Service disconnecting means) happened to be on the main house next to its main breaker.
Here in metro-Atlanta, it's pretty common to find the service equipment mounted on the main house next to the meter, then a "4 - wire feeder" (usually underground) to the secondary structure and in through an LB and over to wherever the load center is.
Again, maybe I'm misunderstanding, but I thought that the new 2020 code was in part to help emergency personnel ensure that power was shut off to the building in question.

I think the new rules will continue to allow service equipment to be installed in the main panel as long as the meter and newly required em disco are installed on the other side of the wall or the service conductors are outside the building (ie under 2" concrete)

I always thought that seeing a row of meters on the outside of a 5 or 6 unit condo seemed to be inherently stupid. If there's a structure fire, it seems smarter to be able to be outside the building and shut everything off from there than have to go inside each unit and turn off power at the panel

sorry for being so long winded

 

[winnie]

My understanding is that a very common installation is as follows:

3 wire from utility (neutral is grounded conductor, no separate EGC) to meter. Then the same 3 wires enter the building and go to the 'main panel' (service equipment) In the 'main panel' you have a single bus used for EGCs and neutrals.
GECs may be connected anywhere from the meter to the main panel.

In prior versions of the code, the 'main panel' was located where the first OCPD was, no exceptions.

The new emergency disconnect rules require a disconnect outside, but permit an OCPD to be used as that disconnect without triggering the 'main panel's requirements. You can have that OCPD outside at the meter, then continue inside with three wires to a panel that has a common bus for neutrals and EGCs. You can land your GECs in that panel. Etc.

Jon