main disconnect Yes or No

[Ponchik]

Main distribution is on the first floor, 600Amp ATS on the 4th floor along with distribution panel that is only for that floor. The distribution panel has (5) 3 pole circuit breakers only.

The question that came up "does the ATS distribution panel require a main disconnect or it can be main lug only"?




On a similar note:
In a commercial office assume there are multiple panels per floor, does each panel require a main disconnect?

Thank you.

 

[Smart $]

Main distribution is on the first floor, 600Amp ATS on the 4th floor along with distribution panel that is only for that floor. The distribution panel has (5) 3 pole circuit breakers only.

The question that came up "does the ATS distribution panel require a main disconnect or it can be main lug only"?




On a similar note:
In a commercial office assume there are multiple panels per floor, does each panel require a main disconnect?

Thank you.

No panel (panelboard and its enclosure) is required to have a main circuit breaker (i.e. within the same enclosure).

Every panelboard is required to have an overcurrent protective device located within or at any point on the supply side of the panelboard.

Additionally, per 2011 NEC...

408.4 Field Identification Required.

(A) Circuit Directory or Circuit Identification. Every circuit
and circuit modification shall be legibly identified as to
its clear, evident, and specific purpose or use. The identification
shall include sufficient detail to allow each circuit to
be distinguished from all others. Spare positions that contain
unused overcurrent devices or switches shall be described
accordingly. The identification shall be included in
a circuit directory that is located on the face or inside of the
panel door in the case of a panelboard, and located at each
switch or circuit breaker in a switchboard. No circuit shall
be described in a manner that depends on transient conditions
of occupancy.

(B) Source of Supply. All switchboards and panelboards
supplied by a feeder in other than one- or two-family dwellings
shall be marked to indicate the device or equipment
where the power supply originates.