We have the following series of breakers and subpanels
Mains -> 200A Main breaker -> 200A Subpanel with 200A breaker
--> 100A Subpanel with 100A breaker --> 30A Subpanel (but no 30A breaker)
The 30A Subpanel consists of 6 20A breakers that connect directly (via
the busses) to the 30A incoming line.
Now there is a 30A breaker on the 100A Subpanel but *no* 30A breaker
on the final 30A subpanel. The 30A subpanel is located across the
house from the other panels which are all located in the basement.
Is there any problem with not having (another) 30A breaker in the 30A
That's a "service panel" that has to have 6 or less switches (and a 2
pole breaker with the handles tied counts as only 1.) I don't think
there's any such requirement for a subpanel -- unless it is located in a
separate building (in which case it's treated like a service panel)
The "6 handle rule" basicly says that no more than 6 hand motions
shall be required to disconnect power to a building, or occupancy.
The 6 handles may be fused disconnects or circuit breakers rated at 30 amps
or greater. Fire pump, and emergency lighting supplied as separate services
are excluded from the 6 handle count.
Subpanels must be protected by overcurrent protection not greater than the
rating of the subpanel.
Feeders must be protected by overcurrent protection not greater than the
capacity of the feeder.
If the overcurrent protection on the feeder is less than or equal to the
subpanel capacity, then no additional protection is required at the subpanel.
In the original example, the 200amp service disconnect would be sufficient
for the 200amp feeder supplying the 200amp subpanel, and no additional
breaker would be required at the 200amp subpanel.
The same would apply to the 100amp feeder to the 100amp subpanel, which would
be protected by the 100amp breaker in the 200amp subpanel.
If the 200 amp feeder supplied 100amp subpanel(s), then 100amp breakers would
be required to protect each subpanel.
-- Welcome My Son, Welcome To The Machine --
Bob Vaughan | techie @ tantivy.net |
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