R302.5/R302.6 (Dwelling Unit Garage Fire Separation) And Electrical Panels

[wwhitney]

2024 IRC R302.5.3 says "Penetrations through the separation required in Section R302.6 shall be protected as required by Section R302.11, Item 4," while 2024 IRC Table R302.6 requires separation on a wall between the dwelling unit and the garage of "Not less than 1/2-inch gypsum board or equivalent applied to the garage side."

Taken together, does that mean if you want to cut through that 1/2" gypsum board for an electrical panel facing the garage (or even an electrical box for a receptacle), all you need is to fill any gap between the panelboard enclosure and the gypsum board with what R302.11, item 4 specifies, namely "an approved material to resist the free passage of flame and products of combustion"?

That's how I read the text, and that's what this 2015 ICC formal interpretation says: https://www3.iccsafe.org/cs/committeeArea/pdf_file/RE_15_04_16.pdf Just wanted to confirm that's correct; is that formal interpretation still "in force," or does it by default apply to only to the 2015 IRC?

Thanks,
Wayne

 

[steveray]

Methinks the panel cover is better than 26 ga...So likely a nonissue...
R302.5.2 Duct Penetration
Ducts in the garage and ducts penetrating the walls or ceilings separating the dwelling from the garage shall be constructed of a minimum No. 26 gage (0.48 mm) sheet steel or other approved material and shall not have openings into the garage.

But yes...you could penetrate it with a 12" PVC pipe and "just fireblock" it...

 

[mtlogcabin]

Methinks the panel cover is better than 26 ga...So likely a nonissue...

Agree, it is the low voltage media/communication boxes that we have to constantly check.
For some reason they want to use the plastic box installed on the garage side of the garage wall, Maybe it is because the 20 gauge metal boxes are twice the price.

We have seen the garage wall designed as a shear wall (seismic) and the electrician cut a huge hole in the wood structural panel to install his panel box.

 

[wwhitney]

Methinks the panel cover is better than 26 ga...So likely a nonissue...

I don't see the relevance, a panelboard enclosure is not a duct, so it would fall under R302.5.3, not R302.5.2.

Agree, it is the low voltage media/communication boxes that we have to constantly check.
For some reason they want to use the plastic box installed on the garage side of the garage wall,

And what code section would prohibit such a plastic box as long as the gaps between it and the drywall are sealed in accordance with R302.11, item 4?

We have seen the garage wall designed as a shear wall (seismic) and the electrician cut a huge hole in the wood structural panel to install his panel box.

As an aside, I would expect that would usually calc out with boundary nailing around the opening, but would require the engineer to consider it. Typical worst case would be some additional detailing, like FTAO straps around the opening.

Cheers, Wayne

 

[steveray]

I don't see the relevance, a panelboard enclosure is not a duct, so it would fall under R302.5.3, not R302.5.2.


And what code section would prohibit such a plastic box as long as the gaps between it and the drywall are sealed in accordance with R302.11, item 4?


As an aside, I would expect that would usually calc out with boundary nailing around the opening, but would require the engineer to consider it. Typical worst case would be some additional detailing, like FTAO straps around the opening.

Cheers, Wayne

It's an example of Sheetmetal withstanding a fire and not allow smoke and hot gases or whatever that section says....If you can have a giant plastic hole just fireblocked, Shirley the 2 layers of metal that a panelboard is, is not a problem.....

 

[mtlogcabin]

And what code section would prohibit such a plastic box as long as the gaps between it and the drywall are sealed in accordance with R302.11, item 4?

I would invoke the "Tiger Code" since these boxes are usually 12" X 12" or larger. If you had a whole in the garage wall that big would you not require it to be covered?