NM terminating in exterior box (here we go again)

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electricmanscott

electricmanscott

Senior Member
Location
Boston, MA
Jim W in Tampa said:
It does not need to be in wet location. Silicon behind it keeps it from being wet or even damp. If your suggesting the inside of the box is wet then we have issues. If inside is wet then why bother with inuse covers ? Properly installed there is no reason for the romex to get wet.
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I guess you have never opened an outdoor box. :confused:
 
G

greenjeans

Inactive, Email Never Verified
Location
Now living in Virgina
I hate it when I open a w/p box and a cup of wet pours out. three things I do to w/p the box 1) duct seal top hole(s) 2) use a romex conn. on back of box and fill hole and around wire with duct seal. 3) duct seal the top back edge of box on house, (sometimes I seal the sides- large openings) gravaty will work after that. I never have water issues in any of my boexs (except for small rust on lower screw, I dont seal the gasket to box, as u cant get them off and reuse.
romex conn extens box into wall more then a 1/4", no more wet location, now,, yes i know conn not rated for wet location -----------thats why i love DUCT SEAL
 
LarryFine

LarryFine

Master Electrician Electric Contractor Richmond VA
Location
Henrico County, VA
Occupation
Electrical Contractor
greenjeans said:
... yes i know conn not rated for wet location -----------thats why i love DUCT SEAL
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Why not use the type of cable clamp that has a rubber gland with an oval hole? It looks a bit like an EMT compression connector.

You also might try my two-1/8"-holes tip.
 
T

ty

Senior Member
Location
3rd Rock from the Sun
If you're really concerned about the A/C disconnect, run SE cable to it.

That would at least stop some people from sleaving the leftover long piece of NM through carflex to the A/C unit. (can of worms opened)
 
goldstar

goldstar

Senior Member
Location
New Jersey
Occupation
Electrical Contractor
Dennis Alwon said:
As I have been told many times by the rep's, nm cable has thhn-2 inside.
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That is correct. The only problem is that the individual wires are not marked and for the life of me I can't understand why but I'd be willing to bet it has something to do with $$$. It sure would make things a lot easier for us folk out here in the field who actually do the work. I guess one more process in the manufacture of NM cable would drive the price up and price us out of the market.:roll:

Come to think of it, I've come across NM cable in some older homes where even the EGC was insulated. Wouldn't that be a treasure for all of us ? We'd best not continue this thread too much longer though; a CMP member may be lurking and before you know it we'll be wiring complete houses with UF cable.;)
 
C

cpal

Senior Member
Location
MA
goldstar said:
That is correct. The only problem is that the individual wires are not marked and for the life of me I can't understand why but I'd be willing to bet it has something to do with $$$. It sure would make things a lot easier for us folk out here in the field who actually do the work. I guess one more process in the manufacture of NM cable would drive the price up and price us out of the market.:roll:

Come to think of it, I've come across NM cable in some older homes where even the EGC was insulated. Wouldn't that be a treasure for all of us ? We'd best not continue this thread too much longer though; a CMP member may be lurking and before you know it we'll be wiring complete houses with UF cable.;)
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Mfg do not want NM in wet locations because of the wicking of moisture along it's length.

It may or may not cause a problem but they have not tested or listed it for such application. They make a cable for such locations UF
 
goldstar

goldstar

Senior Member
Location
New Jersey
Occupation
Electrical Contractor
cpal said:
Mfg do not want NM in wet locations because of the wicking of moisture along it's length.

It may or may not cause a problem but they have not tested or listed it for such application. They make a cable for such locations UF
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Thanks Charlie, I understand about the wicking and NM cable. What I was referring to is labeling the individual conductors inside the NM jacket. If the mfr's did this and marked them as THHN then you could strip away the jacket and use those wires inside a whip to say an A/C unit. I would just make life a lot easier IMHO.
 
T

ty

Senior Member
Location
3rd Rock from the Sun
goldstar said:
Thanks Charlie, I understand about the wicking and NM cable. What I was referring to is labeling the individual conductors inside the NM jacket. If the mfr's did this and marked them as THHN then you could strip away the jacket and use those wires inside a whip to say an A/C unit. I would just make life a lot easier IMHO.
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Wouldn't they need to be marked THWN?
 
quogueelectric

quogueelectric

Senior Member
Location
new york
Dennis Alwon said:
It has always been acceptable to run nm to an exterior box as long as the cable is not run past the exterior wall.

If the argument is that nm does not have exterior wiring in the jacket then it makes sense that we should not allow nm to exit a building at all. I think it has more to do with the jacket but I have heard of some inspectors not allowing nm to enter an exterior box.

This definitely needs clarification. Quite frankly I have never seen any issue with NM run to an exterior panel. NM is installed that way all over the country.
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Toucheee. Great point..........
 
480sparky

480sparky

Senior Member
Location
Iowegia
Jim W in Tampa said:
Your modifing a listed box. If box is installed right why would you need them ?
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Then what good are these types of boxes?

p344_cs.jpg


And why are these made?

7235BB.jpg
 
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