Help in determining wire type for an existing building

nizak

Senior Member
I been called to install additional circuits in a commercial building.

I’m having trouble deciding what the construction classification is.It’s a stick built structure with exterior metal siding and interior finished drywall walls and ceilings.

The attic space where I need to route new circuits through is open wood truss. Past work is all NM cable across and stapled to the side of the trusses and then dropped down in AC cable to either equipment or receptacles.


Since it’s a local job I know that major renovation took place there recently and was permitted through the township.

Im seeing the prior work as not code compliant since it lacks a 15 minute barrier as it’s exposed in the trusses space.

Am I wrong in my thinking?

Thank you.
 
I did forget to mention this is an accessible attic with a stairway and flooring used for storage and HVAC equipment if that mattered.
 
I been called to install additional circuits in a commercial building.

I’m having trouble deciding what the construction classification is.It’s a stick built structure with exterior metal siding and interior finished drywall walls and ceilings.

The attic space where I need to route new circuits through is open wood truss. Past work is all NM cable across and stapled to the side of the trusses and then dropped down in AC cable to either equipment or receptacles.


Since it’s a local job I know that major renovation took place there recently and was permitted through the township.

Im seeing the prior work as not code compliant since it lacks a 15 minute barrier as it’s exposed in the trusses space.

Am I wrong in my thinking?

Thank you.
I think it's concealed in the attic as the drywall is between the nm and the useable areas of the building. The accessible attic with a stairway should be for authrhorized personel only.
 
Interesting. I would have done all AC or MC and been done with it. Why is NM allowed in the attic and not in the walls?

-Hal
I should have clarified. It is dropped down meaning it’s run on the surface of wooden posts that go from the ceiling trusses to the floor.

There are no walls to speak off in the attic. These posts are just a means to support the AC cable and allow for a receptacle to be placed.

There are different types of electronic devices along with some HVAC stuff currently in use.
 
So they ran NM in the attic, then used a JB, spliced, and dropped out, with MC?
That makes no sense.

Im seeing the prior work as not code compliant since it lacks a 15 minute barrier as it’s exposed in the trusses space.
That's not an issue. NM is run in attics and basements all the time.

The issue is, is NM allowed in that class of construction. That's the first thing you need to determine. Go to the township and look up the plans.

-Hal
 
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