We have an inspector that is questioning the installation of SE cable installed for apartment feeders from a meter stack to each unit apartment. The question is there is building insulation in contact with the feeder its entire length. He feels the insulation will prevent adequate heat dissapation and his solution is to remove building insulation every 10' or so to allow the cable to stay cool. He references the fine print note to 310.10. Help!
SE Cable Insulation
- Thread starter jpars
- Start date
- Status
electricman2
Senior Member
- Location
- North Carolina
- Occupation
- Retired Electrical Contractor
Re: SE Cable Insulation
There are probably millions of feet of SE and NM cable out there buried in insulation. If the cable is sized according to all applicable articles and load served there should not be a problem.
There are probably millions of feet of SE and NM cable out there buried in insulation. If the cable is sized according to all applicable articles and load served there should not be a problem.
bphgravity
Senior Member
- Location
- Florida
Re: SE Cable Insulation
Fine Print Notes aren't enforceable, but if the inspector is really serious about the issue, then I would request the calcualtion he used to determine the increased ambient effects the insulation is adding, and exactly how much the temperature will be reduced by removing random sections along the length of the run.
Fine Print Notes aren't enforceable, but if the inspector is really serious about the issue, then I would request the calcualtion he used to determine the increased ambient effects the insulation is adding, and exactly how much the temperature will be reduced by removing random sections along the length of the run.
hurk27
Senior Member
- Location
- Portage, Indiana NEC: 2008
Re: SE Cable Insulation
This could be a catch 22. If this SE cable has a 75c rating and is ran in attic spaces or in outside walls subject to the heating of the sun, It could very well exceed it's rated temperature. This will also depend upon where in the world you are. as the sun can get very hot in Florida. Even romex can get very hot but with a THHN rating of the conductors gives it a 90c rating. But what is one to do as this would be hard to avoid? But just to say it will over heat because it is in insulation is a stretch.
The FPN is there to let us know that 310.10 applies when installing SE cable as interior wiring.
This could be a catch 22. If this SE cable has a 75c rating and is ran in attic spaces or in outside walls subject to the heating of the sun, It could very well exceed it's rated temperature. This will also depend upon where in the world you are. as the sun can get very hot in Florida. Even romex can get very hot but with a THHN rating of the conductors gives it a 90c rating. But what is one to do as this would be hard to avoid? But just to say it will over heat because it is in insulation is a stretch.
The FPN is there to let us know that 310.10 applies when installing SE cable as interior wiring.
- Location
- Illinois
- Occupation
- retired electrician
Re: SE Cable Insulation
As I recall Fred Hartwell cited some studies in the ROP a couple of cycles ago that showed NM and SE cable encased in insulation will fail at or below their 60?C ampacities. This is just from memory and I could be wrong....if I have some time this weekend I will look at my old ROPs.
Don
As I recall Fred Hartwell cited some studies in the ROP a couple of cycles ago that showed NM and SE cable encased in insulation will fail at or below their 60?C ampacities. This is just from memory and I could be wrong....if I have some time this weekend I will look at my old ROPs.
Don
- Status