Hello to all.

I am bidding on a building remodel that will be an event hall on the lower level and an apartment on the 2nd floor. My question is what type of wiring method may I use on the 2nd floor apartment? I understand how article 518.4(A) applies to the event area on the main level. But, article 518.4(B) states that NM cable is permitted in "non-rated" construction. How do I make the determination as to this rating, without going to the AHJ?

I think the apartment is a dwelling area and needs to follow those rules. They are separate occupancies in my opinion.

But I am not the guy making the decision am I?

I would float your plan out there and see what comes from plan review.

Merlin:

"(B) Nonrated Construction. In addition to the wiring methods of 518.4(A), nonmetallic-sheathed cable, Type AC cable, electrical nonmetallic tubing, and rigid nonmetallic conduit shall be permitted to be installed in those buildings or portions thereof that are not required to be of fire-rated construction by the applicable building code.
FPN: Fire-rated construction is the fire-resistive classification used in building codes."

Fire rated construction ratings are determined from the Building Codes that are adopted in your state/area.

Are there any plans? The info you need should be on the cover page of the plans. You may be able to access the local building codes on your state/local websites.

IMHO, the apt floor/assembly ceiling component will be 'rated', probably 1 hr; possibly 2 hr., but this is only my guess.

Actually now that I re-read the plans, the information is given on the cover page. It states "1 hour fire barrier as required per table 508.3.3. However, A footnote states "We will be submitting an application for variance regarding the sprinkler system and seperation requirements due to the historical architecture of the existing building". So, I am not sure. Looks like I will be contacting the Engineer.

Sounds like a plan!! I suggest you get any info from the engineer in writing to CYA

Good advice, when it concerns an Event Hall, any changes that involve the fire codes need good documentation

ANY time you're involved in 'historical architecture' you're off the map....

You'll need to have your hand held by the AHJ and the plan-check crowd.

There will be serious issues WRT what is grandfathered or not.

My last project to be so involved became re-engineered on the fly almost to the final hour.

It's an altogether different experience.

Think of it as design/build/redesign/rebuild.... That's it!