Originally Posted by junkcollector
XHWN conductors cannot be installed underground without a raceway. The only NEC compliant conductors are the ones that are also labeled USE. (UF cable also). Notice that it has to have a U in it for underground. The XHWN has a W in it, so it is listed for wet locations but not direct burial underground. You can find this info in article 310.13 (A) table- Conductor applications and insulations
That's not the question, it is in 2" rigid conduit in the trench with a long radius elbow for the riser on each end going into a 2" LB fitting and then a 5" nipple to pass through the wall.
The question is about requiring the conduit to continue after enterring the building until it is inside the service panel.
So this presents a problem because inside my 2" conduit I have 3 conductors at 1/0 for the subpanel feeder, also I will have 3 conductors of 14 ga. THHN for my 3-way switch. I don't need these to go into the subpanel, but I guess if I have to do that and it's allowed I can.
For that matter, am I allowed to splice the 14 ga. THHN into NM-B cables inside the service panel, and if so is it okay to bond the NM to the service panel ground on each end even though same circuit but one would be bonded to a service panel other than the one from which the circuit originates? I mean, all the grounds are connected...
The problem is I can get my THHN for the run in 50' spoools, so 3 spools will be $33. If I have to get UF-B, I have to get it at $2.05 to buy by the foot and 50 feet is going to be $100+ or I get a 250' spool at $160.
Another question, I'm assuming this is yes, once I'm in the house if I have to run conduit, am I allowed to transition to EMT?
Edit to update: confirmed with AHJ (it's his office hours right now) that these are acceptable.
As for the service mast bracing, I'm planning to do my bracing based on this:
So I'll take some EMT tubing and flatten the ends to make the bolt attachment, attach to the clamp at the top and the roof at the bottom using a carriage bolt. 2 braces in a V shape... I saw something about required angles at some point for guy wires so if I can find that I'll make sure that my angles are in that kind of range unless anybody else has any other guidelines to offer.