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Outdoor electric project - rough in help please

6K views 44 replies 10 participants last post by  Stubbie 
#1 ·
Hi everyone,

Could the pro's please help me figure out a few of the questions for the rough electric I am going to install? I drew this up to make it a bit easier to understand.

Thank you!




Project Information:
• Running 2 - 20A, GFCI circuits from my 200A panel to a 4x4 post outside.
• Will have 2 - single gang outlets at the post. Each with an in-use cover.
• Using GFCI breaker so that I only have to bury the PVC conduit 12" down (rocks here are HORRID).
• The circuits will run from my basement, through my crawlspace, out through the exterior siding, along a 44' long, 12" deep trench and up to the post.
• Using 2 (two )- 1/2" gray PVC conduits with unsheathed individual wires outside.
• I am doing the rough work and then the electrician will make the connections.

Questions (Blue Circle #s)
1. Can I just drill through the rim joists with a long 3/4" bit? There are two, one for the basement and one for the crawlspace under my addition.
2. How do I transition from the NM to the PVC conduit and the unsheathed individual wires? Can I use a deep 4" metal box?
3. Do I just drill a 3/4" hole through the exterior rim joist and siding and run the PVC conduit/caulk it?
4. How do I attach the PVC to the house? There is block foundation about 12" high, then the siding starts. Do I need a "pull box" to run the wires? How high does the hole coming out of the house need to be above grade?
5. How do I attach the PVC? Just normal PVC primer and cement?
6. How do I attach the PVC to the post?
7. What type of box do I use here for my outlets? I have all weather, in-use covers, but I do not understand what type of box the cover attaches to. How high do these outlets have to be?
 
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#35 ·
OhmZoned said:
Sadly, I agree with you. I did that so the metal box would sit flush with the house. I was able to get all of the wires and the outlets into the box, but I feel like it was a tight fit. If I were to redo it I was thinking of cutting a bigger hole in the house (maybe 1.5") and then putting the connector on the back of the box and sealing it all up with duct seal. It would require re-wiring everything in the box, but I kind of agree... shabby. Just didn't want to cut a huge hole into the house. Would you redo it? If I look at 2011 NEC [680.22(A)(3)] it states"At least one 15A or 20A, 125V receptacle is required to be located between 6 ft and 20 ft from the inside walls of a permanently installed pool at a dwelling unit with a maximum height of not more than 6½ ft above the grade or floor." The outlet I have on the post is about 7' from the pool. Also, the outlet along the back of the house should fall within the 10'-20' range as well. I think I am ok, but I cannot find any updates to the NEC for this section. I am from Pennsylvania, just outside of Philadelphia. If I am going to have to redo the box, should I not put NM into the back of it? The connector is a 3/4" NM clamp connector. I do not know if it is rated for two cables, I thought I read that you could do two. My box only has 1 opening on the back. This is a standard clamp connector - can I use two NM cables? Or do I have to split it up? Sounds like I may need a different box. Open to suggestions. Is this a storable pool - wellllll, kind of. According to the NEC, it is not since it is 48" deep. They consider anything over 42" storable. However, the pool IS storable and it does get taken down every year. The filter also does not have a twist lock type plug. Just a standard 3 prong plug.
I doubt very much the 3/4 connector is listed for two cables. Furthermore, when connectors are installed inside the box as you have done the conductors are folded/pinched against the connector. This is a possible short circuit. Cut the bigger hole and install a short section of PVC conduit into the dwelling. Put another box and transmission to THHN/THWN conductors.
 
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#36 ·
Cut the bigger hole and install a short section of PVC conduit into the dwelling. Put another box and transmission to THHN/THWN conductors.
Got it - thank you for calling out where I can improve my work. I am going for correct, not shabby. I should have done it this way the first time. :whistling2:

I was hesitant to cut a bigger hole in the house, but I suppose that is what they make duct seal and caulk for. Also, now that I only have to run the PVC conduit and not get the clamp into a hole, it should only be a 1-1/8" hole, not too bad.

Amazing what experience teaches...

Thanks again, back to the crawlspace...
 
#42 ·
I think I am done! I added a junction box in the crawlspace where I transitioned from NM to THWN. I know it looks like all of the wires are twisted together in this photo, but I can assure you that it is only the grounds that are tied together with the wire nut and then pigtail connected to the metal box.





I ran PVC conduit to the back of the box outside and got rid of my shabby work and that clamp inside. Made for much more room when tucking the wires back in. I also figured that since I have 2 circuits in the same box, I would put electrical tape along the side/contacts for the outlets. This way in case anything moved over time, it would not cause a short.



Got two green lights and the GFCI test works properly...


Thanks to everyone for your help and suggestions.
 
#44 ·
Thanks again to everyone who helped me out on this project. The electrical inspector was here the other day and I PASSED!!! He actually commented that I did a nice job on the work, which was nice to hear.

Many, many thanks to everyone. On to the next project.... never ends.

:thumbsup:
 
#2 ·
There is NO "rough-in" work here. You are doing 95% of the job.

• I am doing the rough work and then the electrician will make the connections.
I've said it many times before, the "final connections" are the EASY and simple part. Everything else is what is difficult and technical. It's like saying I'll assemble and hang the light fixture but I'll let the electrician come out and put the light bulbs in.

You are asking for most of the details about this job. This is where some experience comes into play. Knowing how to do the physical work is only a small fraction of electrical work, yet so many folks think because they can do the physical work electrical work is easy.
I am not knocking you for trying, I'm just saying you are misinformed about the process in general.
 
#3 · (Edited)
Any chance you could instead try to answer a few of the questions? That may be more helpful than telling me that I'm doing 95% of the work and have no experience. Could you tell me where I am misinformed so that I can continue to work on this project and gain the experience I am lacking?

Thanks
 
#4 ·
I am not one for giving step-by-step hand-holding instructions, but I'll try.

1. Yes
2. Yes
3. No, 7/8" for 1/2" conduit
4. Straps. Typically we'd use LB fittings for this. The height of the rim joists, there is no requirement.
5. Just glue, primer not necessary
6. Straps
7. I'd use PVC FS boxes. You can also use standard metallic weatherproof boxes.

I will ask, WHY two conduits? That's way more work than necessary. Just run both circuits in one conduit and stub one box above the other on the post.
 
#5 ·
Thank you - wasn't looking for hand holding, was just looking to fill in some of the gaps in my understanding.

As for the two conduits.... long story... these circuits are going to be used to run a pool, however... it is not the usual twist lock + convenience outlet setup that Article 680 requires for a pool. The pool is one of those cheap-o above ground pools. The pump for the pool is a crappy little plastic pump that works on a normal 3 prong outlet, not the twist-lock kind that the bigger pumps run on.

Originally, I was going to do a single PVC conduit with multiple circuits and then stub the two required boxes at the end and go on with my life. However, in order to run a PVC conduit that could contain both circuits it would have to be 18" deep, or I would have to use RMC at 8" deep. I live in a mountainous area and there are a few monster boulders under my lawn that prevent me from digging more than 12-14" along the run so PVC 18" down was out of the question. Also, I do not want to go through the hassle of threading and bending RMC for the run. I read that if the circuit is GFCI protected from within the house (assuming at the panel), they can be run in 1/2" PVC that is buried only 12" which is as deep as I can go. That's why I did two separate runs of the 1/2 PVC each containing 3 #12 unsheathed individual wires.

Open to other ideas/suggestions if you have them. I realize experience is super important and I appreciate that you are sharing yours. :thumbsup:
 
#6 ·
Well, I see you have a better handle on things than I initially thought, so sorry for the abruptness early on.

There is nothing limiting you to 1/2" conduit or only one circuit. You can definitely use 3/4" and run both circuits in the same conduit.
 
#9 ·
Ah - that makes sense to run multiple circuits in a single conduit. I misread Table 300.5 for the cover / conduit requirements . It says "Residential Branch Circuits Rated 120 volts or less with GFCI protection, 20amps. I read that as "per" conduit - but it basically means I cannot exceed that, so I could not run a 30 amp circuit out to the post, but I could run 2 - 20 amp circuits as long as I used a properly sized conduit. That is quite helpful. I already have 20' of 1" schedule 40 PVC that I can use though I may just buy all 3/4 to get proper fittings.

Sounds like I need to hit up the store and start buying parts and laying things out.

1. I would prefer to have 2 hots, 2 neutrals, but is a ground a ground? Or do I need a ground for each circuit since I will be using a GFCI breaker?

2. Can I run both NM cables through the same hole in the rim joist?

3. Can I run 2 - #12 NM cables from the breaker to a single 4x4 junction box and then connect each one to the TWHN like I would any other connection? I believe that would be 13.5" of fill space required which a 4x4 metal deep box would cover.

I am going to get #12 - TWHN for the conduit. Knockout for 3/4" is 1-1/8 or 1-3/8 if i use the 1" PVC. Then I would use use single gang boxes at the end of the run on the post. I don't have more than 360 degrees of turn on the run either.

Thanks for the help - I think I am in much better shape than I was 24 hours ago.
 
#11 ·
Since you plan to run as 2 separate circuits(as opposed to a multiwire), I would install 2 GFCI receptacles below the panel and use regular breakers. Run the 2 circuits off the load side. 2 GFCI recep. are a lot cheaper than a 2 pole breaker ($70 -100 depending on brand).
 
#14 ·
Why not go one step further and put the 2 GFCI receptacles in a double box on the outside of the house? That way he would gain 2 additional outside receptacles and could use the same box to make this splice between NM and TWHN for the underground run.
 
#15 ·
Thanks for all of the information everyone...really great . :thumbup: I will try to address each of your points below. Also have a few questions …. Sorry if I seem all over the place, just the way I think, but I am piecing it all together, lots of information to process/consume.

I am going to run 3/4" conduit.
2 hots, 2 neutrals, and a ground #12, TWHN
2 - GE Single pole 20 amp standard breakers
GFCI blank or Outlet on run to obtain GFCI protection (if possible)

I like the idea of adding another box to the outside of the house (or at the panel) and using that to make my connections from inside to the outside.

Can I put the 2 GFCI outlets outside if I am only running the PCV conduit 12" deep ? Remember: 12" instead of 18" due to rocks. :wallbash:

Does the GFCI protection have to originate from within the house (maybe a "non-wet" location?) in order to qualify for the 12" instead of the standard 18"?

If I can install both circuits in a 2 gang outdoor box to make my transition from NM to the THWN run, that would be excellent. Even if I had to use one GFCI outlet and a GFCI blank (if the 1 circuit for the pool has to be "dedicated" and only have one outlet on the line, but I am not sure if that is the case (Article 680.22).

I thought I read that the outlet for the pool must consist of a single (dedicated) outlet. I took that to read as "there can be no other outlets/devices on this entire circuit. Now if I re-read 680.22 (link) I see that it says "(1) Consist of a single receptacle," does that mean I cannot use a 2 gang box at the end for the outlets at the post, but I can add another GFCI outlet somewhere along the run (i.e. at the house to make the transition from indoor/outdoor?

Do I just use a standard NM clamp connector to go from NM inside the house, through the rim joist into the back of the box that is outside and attached to the house? Then duct putty or caulk around/behind the box/around the clamp and use an in-use cover/weatherproof box setup?

Going to go shopping this week to get my parts and hopefully start to assemble next weekend.
 
#18 ·
What about UF cable from the panel to the first GFCI outlet/outdoor box and then transition to THWN? Otherwise, it sounds like I still need to make a junction inside of the house with the PVC and NM hitting the same box and then going out through the rim joist in PVC outside to the GFCI outlet/box along the house.
 
#21 ·
Morning everyone -

What is the best way to transition from indoor to outdoor? If I can use NM into the back of a weatherproof box (attached to the house), then I can just transition from NM to THWN in the box outside and set my GFCI outlets there.

If I cannot connect NM to the back to the outdoor box it sounds like I may have to go NM inside to a J-box, then PVC from the box to the outdoor box+GFCI outlets, then THWN from there to the final outlets.
 
#22 ·
Morning everyone -

What is the best way to transition from indoor to outdoor? If I can use NM into the back of a weatherproof box (attached to the house), then I can just transition from NM to THWN in the box outside and set my GFCI outlets there.

If I cannot connect NM to the back to the outdoor box it sounds like I may have to go NM inside to a J-box, then PVC from the box to the outdoor box+GFCI outlets, then THWN from there to the final outlets.
That is the way I would do it and not miss a beat.
 
#25 ·
I got all of my SCH40 PVC conduit run and glued together, now I am going to pull through my wires.

I just want to confirm - am I allowed to have 2 separate circuits run into a double gang 4x4 box? From here each circuit will connect to a GFCI outlet and then from the load side, I am going to run 12G THWN out to the post in the yard where each circuit will terminate in a single gang outlet.

Are you allowed to have 2 separate circuits power 2 separate outlets in the same box? Or should I just use this 4x4 box as a junction box and skip the outlets? I did like the outlet idea.



Thanks!
 
#34 ·
connector in the box. shabby.
Sadly, I agree with you. I did that so the metal box would sit flush with the house. I was able to get all of the wires and the outlets into the box, but I feel like it was a tight fit. If I were to redo it I was thinking of cutting a bigger hole in the house (maybe 1.5") and then putting the connector on the back of the box and sealing it all up with duct seal. It would require re-wiring everything in the box, but I kind of agree... shabby. Just didn't want to cut a huge hole into the house. Would you redo it?





Be careful where you locate the convenience receptacle. If memory serves, it has to be within 20' of, but not closer than 10' to the pool.
If I look at 2011 NEC [680.22(A)(3)] it states"At least one 15A or 20A, 125V receptacle is required to be located between 6 ft and 20 ft from the inside walls of a permanently installed pool at a dwelling unit with a maximum height of not more than 6½ ft above the grade or floor." The outlet I have on the post is about 7' from the pool. Also, the outlet along the back of the house should fall within the 10'-20' range as well. I think I am ok, but I cannot find any updates to the NEC for this section.

But article 440 does not specifically state that romex is only permitted inside the dwelling unit. As for an inspector questioning it, you've never worked in New Jersey. Where is the op from?
I am from Pennsylvania, just outside of Philadelphia. If I am going to have to redo the box, should I not put NM into the back of it?

Is that connector listed for two cables. Is this a storable pool?
The connector is a 3/4" NM clamp connector. I do not know if it is rated for two cables, I thought I read that you could do two. My box only has 1 opening on the back. This is a standard clamp connector - can I use two NM cables? Or do I have to split it up? Sounds like I may need a different box. Open to suggestions.

Is this a storable pool - wellllll, kind of. According to the NEC, it is not since it is 48" deep. They consider anything over 42" storable. However, the pool IS storable and it does get taken down every year. The filter also does not have a twist lock type plug. Just a standard 3 prong plug.
 
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