CB Panel on Property Line Wall

[DSamson]

My customer wants me to put a CB panel on an exterior property line wall. The building inspector says its a fire-rated wall. He says, o.k. to put a piece of 5/8 rock behind it to maintain the rating. The electrical inspector says, there's no way to put a panel in a fire rated wall that's acceptable to him.

This is a 3 story residence adjacent to a 1 story residence. The wall in question shares a property line, but is on the top floor, so it doesn't touch any part of the neighbor's house, by at least 15 feet. This is a 100 yr old structure, lath on plaster on my side of the wall.

Any good ideas?

Thanks.

 

[Jim W in Tampa]

If you use fire rated wall i simply do dot see his issue. Ask him and fire marshall. I have done it and passed and fire marshall made the specs. If an extral 5/8 is problem then give it to him. This is not NEC but fire marshall ok is what you need

 

[mcclary's electrical]

My customer wants me to put a CB panel on an exterior property line wall. The building inspector says its a fire-rated wall. He says, o.k. to put a piece of 5/8 rock behind it to maintain the rating. The electrical inspector says, there's no way to put a panel in a fire rated wall that's acceptable to him.

This is a 3 story residence adjacent to a 1 story residence. The wall in question shares a property line, but is on the top floor, so it doesn't touch any part of the neighbor's house, by at least 15 feet. This is a 100 yr old structure, lath on plaster on my side of the wall.

Any good ideas?

Thanks.

First off,,,that's only a firewall if the neighbor is closer than 3 feet. If that's true, He's right, you cannot put a panel "IN" a fire wall,,,,however, you CAN put one "ON" a fire wall. If your friend doesn't like surface mount. Frame the whole wall. Your panel is then, not in the fire wall,,,but in the framed wall. I've done this several times.

 

[Jim W in Tampa]

Ask him if he will accept a second piece of 5/8 fire rated drywall behind panel and box it on all 4 sides and use fire calk. I did this once to solve what one of our not so brite had done. Wasnt easy but feeders and circuits were allready in. I actually had 1 1/4 of drywall behind panel. It was suggested by fire marshall.

 

[VoltzElectric]

Just did a job like this. I had to put 2 5/8" drywall around my panel, and fire caulk the whole install. Was required by the fire marshall and building inspector.

 

[e57]

First off,,,that's only a firewall if the neighbor is closer than 3 feet. If that's true, He's right, you cannot put a panel "IN" a fire wall,,,,however, you CAN put one "ON" a fire wall. If your friend doesn't like surface mount. Frame the whole wall. Your panel is then, not in the fire wall,,,but in the framed wall. I've done this several times.

Odds are the neighboring building is <1/2" away this area has buildings butted right up to the property line in most places locally. And the wall idea is a good one... I have done it... If this were a 'new' building - it may have '1 hour Type X' sheathing or 1" rock barrier - but odds are that this place only has 80 YO tar paper, and clap-board right against the next building.... :roll:

As for local inspectors - if it is female (young one or the older ones) forget about it - they have 4X8x10' gluelams on each shoulder! If it one of the male ones, (senior or what is left of the usually feild guys) then educating yourself, pleading past ignorance, prove your new found knowledge, offer to correct, and swear you'll "NEVER DO THAT AGAIN" and they might let it slide.... But either way consider it a leason learned.... :roll: And odds are you may need to move it....

FYI Fire penetrations have become a pet-peeve for all of the building and trade inspectors lately - so expect some serious enforcement for all electrical penatrations of fire rating envelopes - resi~commercial, condo~condo, garages, common area or PL. Especially, 4 stories or more where the building would require sprinklers and a fire marshall inspection.

Good ideas - are few... The wall on wall idea is a good one.... Use some well placed blasting agent to remove the lath and plaster. Mineral wool batt insulation. Rock and tape it with Type X, seal your penetrations of that wall when you bring all cabling out of that wall into the new wall have it inspected by the building and electrical. Then build a new wall.... And just for S&G use metal studs - leave this open for inspection... By all means have a copy of the wall assembely detail - (typical to these although the one you need is not in this one. ) and the fire caulk used to seal all the holes where the cable went through - have them all in your hand.


After the money you spent on all the re-inspection - have a beer and consider it a really expensive course in fire-rated penetrations.

 

[DSamson]

Thanks all for your input.

Fortunately, I haven't done it yet, so no expensive lesson.

Also, just to clarify, this is a shared property line, buildings are right up against each other. Proposed panel location is at least 15 feet vertical from the top of the adjacent building.