NM to THHN/THWN

[dszrew]

running NM through a wall. need power through a hole in the foundation then outside using THHN/THWN. do I put the junction box inside to join NM & THHN then through the foundation, or can I put the box outside and run NM through the hold in the foundation?

 

[wyliesdiesels]

NM cannot be ran through the foundation.

J box goes on the inside, then the THWN can be ran through conduit running through the foundation. Dont run the THWN without being in conduit.

BTW THHN is dry location only but most is dual rated THWN

 

[Terry D]

I would put the j box inside, run your NM to the box, switch over in the j-box to THWN and have conduit out the back of box to a LB outside.

 

[dszrew]

that's what I needed to know.
in my case, I have the wiring coming through a basement cold storage room, will drill through the foundation into a bedroom, run through the wall, then outside through the foundation. that means I need two covered junctions inside the bedroom (one in, one out), but was hoping to avoid that.

alternatively, I guess I could run THWN into the bedroom and through a conduit and have no junction boxes at all?

 

[pattenp]

NEC doesn't prohibit NM from passing through masonry wall via a bored hole. NM is not to embedded in masonry or concrete. Use a short piece of PVC conduit as a sleeve to protect from abrasion.

 

[dszrew]

NEC doesn't prohibit NM from passing through masonry wall via a bored hole. NM is not to embedded in masonry or concrete. Use a short piece of PVC conduit as a sleeve to protect from abrasion.

the NM will end up outside in a junction box where it will tie into THHN and then run through conduit. it seems that NM to the junction box outside is OK, but not any further, correct? just needs a waterproof junction box outside?

 

[pattenp]

the NM will end up outside in a junction box where it will tie into THHN and then run through conduit. it seems that NM to the junction box outside is OK, but not any further, correct? just needs a waterproof junction box outside?

That's okay, but run a short piece of conduit from back of box through foundation to pass NM through.

 

[wyliesdiesels]

NEC doesn't prohibit NM from passing through masonry wall via a bored hole. NM is not to embedded in masonry or concrete. Use a short piece of PVC conduit as a sleeve to protect from abrasion.

my bad. I was thinking of the code that prohibits it from being embedded and typed my comment to fast before thinking about it.

 

[pbon]

If you have space to run conduit through the bedroom and could eliminate a junction box, that is worth considering.

 

[mike93lx]

Is this just an outlet on the exterior of the building or is the wire running further?