Grouping disconnects revisited

[jar546]

Please, one more time with new information available.

A townhouse is clearly specified as being a "separate building" whereas each side/up-down of a 2-family is considered a "dwelling unit" and is not specified as a separate building like a townhouse is. Townhouse=Separate building and 2 hour separation(NS) and a 2-Family is not considered separate buildings and is only required a 1 hour separation(NS).

Thinking about electrical, do we have to look at 2 family units as 1 building/structure for purposes of grouping disconnects?

 

[north star]

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If the 2 family units [ meaning "each" 2 family unit - the upstairs &

the downstairs ], are an "all encompassing" structure unto themselves,

and have the proper fire rated separation at any point of connection

to other parts of a structure, I would say "yes", they would be

considered a single structure.

From Article 100 [ `08 NEC ]: Building - a structure that stands

alone or that is cut off from adjoining structures by fire walls,

with all openings therein protected by approved fire doors.

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[jar546]

1 hour separation does not meet the definition of "firewall"

 

[north star]

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I stand corrected kind sir, with regard to the use of the definition

of a "separate" building & fire walls.....I would still consider the

structure to be a single building though!

FWIW, the `08 NEC HAndbook has some excellent drawings of

the various disconnect groupings on structures.

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