Electrical code clarifications

[shenandoah75]

Well, I bought over 800' of 3/4 conduit and 200' of 3/4 PVC yday and have started trenching/laying. My goal is to start outwards and work my way to the house. I think i've gotten some code clarification here before and hope that's ok to ask again:


Basics: (4) 20A circuits coming off GFI breakers to a panel/project box with contactors whose coils are controlled by 24VAC off the elk - romex to the contactors. Outbound via single runs of 10AWG stranded/color coded (red/black/white) THWN (went 10AWG because of the voltage drop over 100'+ distances and stranded cause that's all Lowes has in 10AWG and easier to pull. Green 12 AWG solid for grouns. I will keep all my runs at 4 90 degree bends or less so as not to exceed the 360 degree rule i was reading from NEC. I will basically run two crcuits to each 2 gang box (hense the red/black) and share the neutral/ground.


Questions

1) i read somewhere in an online electrical forum that plastic conduit is a no/no once you're indoors. Is this true and if so, true for exposed items / high voltage only/etc? I've used conduit to get low voltage wire between stories to get from my LV panels up into the attic, etc before. Was hoping just to bring the wire into block walls via plastic LBs and then plastic up the walls and into the attic for these circuits too...

2) Related to #1, I am pretty sure uncovered THWN in the attic is a no no, so again, was hoping not to transition to metal up there. If i have to, where is the best place/approach to do it? I was thinking maybe junction boxes in the attic and taking romex (no conduit) from contactors to there ad then transitioning to the single strands from that point on.

3) from my reading, once i leave the house, romex is a no-no even in conduit... so if i transition outside, i guess i'm forced to use UF/THWN for an inline box right on the exterior wall (even if it's on it's own circuit)?

4) i also read that solid is ideal for terminating outlets. Will i have problems with the stranded? Or can/short i buy a short amounts of 12AWG solid THWN and wire nut it to the feeds to make the connections easier?

5) Is there a problem putting an outlet and hose bib of opposite ends of a 4x4 post coming out of the ground and if so what's the spacing requirement?

6) likewise, any distance requirements on the wall of the house. I've got a hose bib mounted on the narrow corner wall next to my garage door and would like to put outlets close by. I think from simple reasoning on my part, i probably would prefer to put them around the corner, but is that enough?



thx in advance
-brad

 

[Sandpiper]

1) i read somewhere in an online electrical forum that plastic conduit is a no/no once you're indoors. Is this true and if so, true for exposed items / high voltage only/etc? I've used conduit to get low voltage wire between stories to get from my LV panels up into the attic, etc before. Was hoping just to bring the wire into block walls via plastic LBs and then plastic up the walls and into the attic for these circuits too...

2) Related to #1, I am pretty sure uncovered THWN in the attic is a no no, so again, was hoping not to transition to metal up there. If i have to, where is the best place/approach to do it? I was thinking maybe junction boxes in the attic and taking romex (no conduit) from contactors to there ad then transitioning to the single strands from that point on.

3) from my reading, once i leave the house, romex is a no-no even in conduit... so if i transition outside, i guess i'm forced to use UF/THWN for an inline box right on the exterior wall (even if it's on it's own circuit)?

4) i also read that solid is ideal for terminating outlets. Will i have problems with the stranded? Or can/short i buy a short amounts of 12AWG solid THWN and wire nut it to the feeds to make the connections easier?

5) Is there a problem putting an outlet and hose bib of opposite ends of a 4x4 post coming out of the ground and if so what's the spacing requirement?

6) likewise, any distance requirements on the wall of the house. I've got a hose bib mounted on the narrow corner wall next to my garage door and would like to put outlets close by. I think from simple reasoning on my part, i probably would prefer to put them around the corner, but is that enough?

1) PVC rigid conduit (called RNC in the code) is allowed indoors in concealed and exposed locations, as well as outdoors in damp and wet locations. This is covered by Article 352 in the NEC.
2) Single conductor THWN would have to be put into some type of conduit, but it can be plastic, metal, rigid or flexible. Romex (called NM in the NEC) would not need conduit for use in the attic.
3) Correct. Romex cannot be used in damp or wet locations. UF is made for this purpose. UF may be put in conduit or direct buried. However, UF may also be used anywhere Romex can. So you may want to use UF all the way without a junction point. (NEC article 340)
4) If you use the type of outlets that have a terminating clamp (as opposed to the type with a only a screw or a hole) you wont have a problem. These type are very common now and can be found a the local building supply stores.
5) The is no spacing requirement for where to put an outlet outdoors. All outdoor locations are considered to be wet (or damp) locations. And so, each is required to be protected by GFCI, and also to be covered by a weatherproof cover.
6) Same answer as 5).

 

[shenandoah75]

Many thanks...

FYI, with a telephone company that loves to trench with machines, a cable company that barely put the cable below the surface, and power lines buried in the ground, and semi frequent repairs/changes to irrigation, i just didn't want to deal with the risks UF poses nor the lack of flexibility. Ya i pay a little more up front, but i'm somewhat protecting from shovels in the future this way. And i'm running two conduits for electrical in each trench - one for the high voltage and one for the lV landscape lighting (which i didn't feel like forking out $$ for wire for until i'm ready.

I really thought about it, but i think i'll be happier and feel like it was worth it in the long run.

thx again
-brad