service disconnect verses main disconnect.

Status
Not open for further replies.
transfer switches with breaker in them are being called main disconnect by inspectors.
but you turn it of and generator comes on in 30 or so seconds.
so the main disconnect should be the main breaker in the breaker panel.
I would like proper clarification.
thanks.qugh devaj
 

Coppersmith

Senior Member
Location
Tampa, FL, USA
Occupation
Electrical Contractor
Transfer switches with main breakers are called "service rated" because the main breaker can be the "service disconnect" for the utility power but is not necessarily so.

If there is no disconnect between the meter and the transfer switch, the main breaker in the transfer switch is the "service disconnect". If there is a disconnect ahead of the transfer switch, the main breaker in the transfer switch is a "main disconnect".

The generator itself has a main breaker which is a "service disconnect" according to 230.72(B).

230.72 Grouping of Disconnects.
(B) Additional Service Disconnecting Means. The one or
more additional service disconnecting means for fire
pumps, emergency systems, legally required standby, or optional
standby services permitted by 230.2 shall be installed
remote from the one to six service disconnecting means for
normal service to minimize the possibility of simultaneous
interruption of supply.
 
service disconnect

service disconnect

the ATS breaker is for servicing the transfer switch after locating the generator and turning of the breaker and disconnecting the battery.
the main disconnect for the breaker is still the main in the panel.
this is how I see it.
you cannot have a main disconnect and a breaker to also turn on in two different locations.
 

augie47

Moderator
Staff member
Location
Tennessee
Occupation
State Electrical Inspector (Retired)
I think if you look at the NEC definition of services, service conductors, and service disconnects, the 1st point of disconnect (of service conductors) is going to be the "Service Disconnect" ("meter disconnects" as allowed by 230.82 being an exception).
If the ATS is service rated and connected to the service conductors, the ATS main is the Service Disconnect.
I don;t recall a NEC definition of a "Main Disconnect"
 
Last edited:
Status
Not open for further replies.
Top