Multifamily home built in 1901. Obviously upgraded electrical system along the way. Wondering how to describe each panel in the situation below.
3 electrical meters. There is a service panel upstream of the meters with a 100 amp disconnect. Grounding electrodes appear to leave the box below it, however they were not connected to anything (looks like the were disconnected from copper main water pipe.
After that service panel are the meters, with a panel below each meter. Are these panels (1 for each apartment) still considered service panels? Can you have 2 service panels serving the same unit (the common one before the meter and the specific one to each unit)?
I ask not only so I get the nomenclature right, but because the shared bus for ground and neutrals becomes relevant depending on what these individual panels should be considered. Also, the panels specific to each unit don’t have main disconnects and two of them have more than 6 breakers.
Typically I don’t see that panel with disconnect BEFORE the meter on multiunit homes, which is what is causing me the confusion. Usually the panels right after the meters are the service panels. Thanks.
No meter before that panel in the upper right corner. SECs came right in through the front wall and into that panel with the 100amp disconnect. Then the 3 meters, then the individual panels for the 3 apartments.
Technically the service panel is the first point of disconnect. So all panels after that are considered subpanels. And the GEC typically comes from the meter.
But I have also never seen the disconnect before the meter either
Service panel is the first point of disconnect.
The main distribution panel connects to the electric power feed to the house and divide the electrical current into circuits. Each circuit has a breaker, or a fuse, which is housed on distribution panels in the breaker or fuse box.
A remote/sub/auxiliary panel is a smaller service panel that distributes power to a specific area of the home or other buildings on the property.
Hope I explained it properly.
Just to make things even more confusing the 2020 NEC now requires a disconnect on the outside of dwellings so with new installations you may find a disconnect next to the meter that is not the service disconnect. There is also a new labelling requirement to indicate what the actual function of the disconnect is.
So is that panel on the upper right a service panel or just a disconnect? By Robert Y’s description, it sounds like the service disconnect was the panel before the meters and the panels immediately after the meters for each individual apartment are main distribution panels for the respective apartment. Did I understand correctly? If they are distribution panels and not service panels, I assume that means the neutral bus bar should be floating and the grounds shouldn’t be on the same bus…
Robert M, if a disconnect is now required outside the home, is that considered the “main disconnect” or is the main still inside the service panel? When you say a disconnect is outside the home, does it have to be a pull-out, breaker, switch, or any type?
The outside disconnect can be any suitable disconnect switch. It may or may not be the service disconnect based on how it is wired and labeled. Here is the new 2020 NEC disconnect and labeling requirement:
230.85 Emergency Disconnects.
For one- and two-family dwelling units, all service conductors shall terminate in disconnecting means having a short-circuit current rating equal to or greater than the available fault current, installed in a readily accessible outdoor location. If more than one disconnect is provided, they shall be grouped. Each disconnect shall be one of the following:
(1) Service disconnects marked as follows:
EMERGENCY DISCONNECT,
SERVICE DISCONNECT
(2) Meter disconnects installed per 230.82(3) and marked as follows:
EMERGENCY DISCONNECT,
METER DISCONNECT,
NOT SERVICE EQUIPMENT
(3) Other listed disconnect switches or circuit breakers on the supply side of each service disconnect that are suitable for use as service equipment and marked as follows:
EMERGENCY DISCONNECT,
NOT SERVICE EQUIPMENT
Markings shall comply with 110.21(B).
