Residential question

[Dennis Alwon]

Another suggestion for exterior panels is to cut a slot (or series of holes) in the wall five inches below the exterior panel, run the cables though the slot and fasten with connectors to the bottom of the panel. Fasten a pressure treated 1x2 between the panel and the slot and staple the cables down. Have a weatherproof metal cover fabricated that is six inches tall and the width of the panel. Fasten it to the bottom of the panel and the wall. The cover will protect the cables from physical and weather damage. I'd check with the inspector first to make sure they will accept this arrangement since the cover is not listed.

That would be a total nightmare to seal and to prevent water damage. 30 years ago an inspector wanted me to do that. I called the head engineer for the state and he put a stop to that demand.

 

[Dennis Alwon]

Yeah, and I should have mentioned can do 60% fill up to 24”, and over 24”derating is required 310.15(B)(2)(a) and notes to tables (4) in Chapter 9. So you can get close but not quite there.

But I missed the outdoor part and NM. Probably need to go back to the drawing board.

Chris Note 4 is talking about a conduit run between boxes or cabinets not a sleeve. No derating IMO if under 24" and no fill restrictions

(4) Where conduit or tubing nipples having a maximum
length not to exceed 600 mm (24 in.) are installed
between boxes, cabinets, and similar enclosures, the
nipples shall be permitted to be filled to 60 percent of
their total cross-sectional area, and 310.15(B)(3)(a)
adjustment factors need not apply to this condition.

 

[Coppersmith]

That would be a total nightmare to seal and to prevent water damage.

I'm not sure why it would be a nightmare. There are reliable methods of sealing wall penetrations and there is that weatherproof cover as well.

 

[hbiss]

Another suggestion for exterior panels is to cut a slot (or series of holes) in the wall five inches below the exterior panel, run the cables though the slot and fasten with connectors to the bottom of the panel. Fasten a pressure treated 1x2 between the panel and the slot and staple the cables down. Have a weatherproof metal cover fabricated that is six inches tall and the width of the panel. Fasten it to the bottom of the panel and the wall. The cover will protect the cables from physical and weather damage. I'd check with the inspector first to make sure they will accept this arrangement since the cover is not listed.

I remember from a similar thread to this several years ago that there is a manufacturer that actually makes such a thing.

Not that I would advocate a panel located outside of a house.

-Hal

 

[Cletis]

I think a lot of the new cable bundling is hogwash anyhow. there is plenty of dissipation for heat. The problem now I think is that houses are getting foam sprayed and have no heat escape at all anymore. That's much more of a problem

 

[electricman2]

The installation described by the OP is common around here. The only thing the inspector requires is that the cables are secured before they enter the male adapter into the back of the panel. We do this by placing a 2 x 4 between the studs installed edgewise and staple the cables to it.

 

[roger]

I plan on sealing with expanding foam when done.

Just a heads up, I had an inspector want back up that expanding foam was listed for use in direct contact with conductors once. I contacted Dupont and they beat around the bush but would not help me in the end. It wasn't a total disaster but in the end it was a PIA.

Roger

 

[roger]

Not all AHJs are sharp nor enforces all codes...
got one here that is basically lazy and won’t look hard, especially if he knows you..
only looks at the simple stuff.. 2 rods, grounds in boxes tied together (checks one or two boxes), and a light in crawlspace. Only bends over, won’t actually go in...

Might his first name be Don?

Roger

 

[Little Bill]

Just a heads up, I had an inspector want back up that expanding foam was listed for use in direct contact with conductors once. I contacted Dupont and they beat around the bush but would not help me in the end. It wasn't a total disaster but in the end it was a PIA.

Roger

I was at a meeting here a few years ago with inspectors and other electricians. I ask about the new, at the time, requirement to seal entrances into panels. I ask if the expanding foam could be used. Without batting en eye, most of the inspectors responded with a unanimous NO. Apparently they had checked it out prior and told us that it wasn't rated for direct contact with wiring. One went as far as to say it was flammable. I never fact checked them since they weren't going to allow it anyway. I just use duct seal and move on.

 

[Hv&Lv]

I was at a meeting here a few years ago with inspectors and other electricians. I ask about the new, at the time, requirement to seal entrances into panels. I ask if the expanding foam could be used. Without batting en eye, most of the inspectors responded with a unanimous NO. Apparently they had checked it out prior and told us that it wasn't rated for direct contact with wiring. One went as far as to say it was flammable. I never fact checked them since they weren't going to allow it anyway. I just use duct seal and move on.

That makes absolutely no sense whatsoever.
Plenty of houses now have spray foam insulation in the walls and ceilings..

They fail all of them??

 

[Hv&Lv]

Just a heads up, I had an inspector want back up that expanding foam was listed for use in direct contact with conductors once. I contacted Dupont and they beat around the bush but would not help me in the end. It wasn't a total disaster but in the end it was a PIA.

Roger

They fail the expanding foam used in houses for insulation in walls and ceilings?

Here DuPont recommends it

How To

www.greatstuff.dupont.com

 

[Little Bill]

That makes absolutely no sense whatsoever.
Plenty of houses now have spray foam insulation in the walls and ceilings..

They fail all of them??

I never said it made sense and I even stated I didn't fact check them. Not worth the effort so I just use duct seal. I too have seen lots of wiring covered with the stuff in the attic and crawl spaces.

 

[Hv&Lv]

I never said it made sense and I even stated I didn't fact check them. Not worth the effort so I just use duct seal. I too have seen lots of wiring covered with the stuff in the attic and crawl spaces.

It’s amazing to me that sometimes it seems those that can’t do the job get to inspect those that can...

 

[roger]

They fail the expanding foam used in houses for insulation in walls and ceilings?

Here DuPont recommends it

How To

www.greatstuff.dupont.com

Take note that the "Great Stuff Pro" and "Fireblock" products is not standard expanding foam and I don't believe was even made when I tried to get Duponts help.

Roger

 

[olly]

Quite frankly it is because there really isn't a better way to do this with an outdoor panel. Sure you can add a jb inside and splice all the wires but is that really better?

If I drill a bunch of 1/2" holes and install romex connectors, Is there any concern around romex being exposed to weather. Since the panel sits roughly an 1/8" off of the siding? It sits an 1/8 off because you know how they put indentation where the mounting screw goes. Again WP breaker panel mounted to the exterior of a building.

 

[chrismarcellino]

That makes absolutely no sense whatsoever.
Plenty of houses now have spray foam insulation in the walls and ceilings..

They fail all of them??

The comment was regarding sealing entrances to panels, or the open end of the accessible short conduit allowed by 312.5(c), which the NEC stipulates must be sealed. In either case, a flammable foam (115 C ignition point for Great Stuff) is less useful than any other material, and more work to add future wiring work. (If the panel is designed to contain an arc flash or bolted on fault etc,. best to not make a cannon out of it.)

No issues in the walls, attic or outside of otherwise permitted fittings, etc. of course. Wasn't try to suggest against the use of spray foam as insulation or draft sealing, for which it is awesome. I'm no inspector, but if I can see the spray foam from inside the panel or conduit, I would fail it. Just my opinion though.

 

[chrismarcellino]

If I drill a bunch of 1/2" holes and install romex connectors, Is there any concern around romex being exposed to weather. Since the panel sits roughly an 1/8" off of the siding? It sits an 1/8 off because you know how they put indentation where the mounting screw goes. Again WP breaker panel mounted to the exterior of a building.

334.10(A)(1) requires NM to be in a normally dry location. (A location not normally subject to dampness or wetness, which is different than damp or wet.) This basically includes anything outside of siding or subject to condensation.

I take it you can't use NMC or UF-B of the same size for the last runs to the panel? It's only about double the cost and I hear not too much more painful to work. Mind the bend radii but would be permitted in damp or wet locations respectively. With UF, you can come right in the panel any direction that is not subject to damage and is secured at the panel (assuming it is marked sunlight resistant or not visibly exposed). Still need to secure in pairs (with listed connectors that permit) to the panel in individual knockouts.

I'm sure there are a bunch of other ways to solve this that are compliant that the electricians can suggest.... If you can fashion a flashed covering outside that your AHJ would approve, an attic feeder, JB, etc. Can you describe your options better for the other sparky's here?

 

[Dennis Alwon]

Chris--UF is an outdoor cable so I don't get what you are saying. True you cannot run nm in a conduit outdoors (NC allows it up to 6') but uf can be run outdoors

 

[chrismarcellino]

Chris--UF is an outdoor cable so I don't get what you are saying. True you cannot run nm in a conduit outdoors (NC allows it up to 6') but uf can be run outdoors

Right---olly is wishing to run NM ("romex") outdoors if I am understanding his post correctly (ignoring the part about needed to secure the cable to the panel). I am suggesting he consider UF outdoors.

 

[Dennis Alwon]

Right---olly is wishing to run NM ("romex") outdoors if I am understanding his post correctly (ignoring the part about needed to secure the cable to the panel). I am suggesting he consider UF outdoors.

It didn't sound like that

I take it you can't use NMC or UF-B of the same size for the last runs to the panel?