Romex in PVC Conduit?

[jtd771]

I have a garage that although attached to the house there is no way to run wire from the main panel in the house to the garage without going outside. The distance along an exterior wall from where I would exit the house to the garage where it would enter is about 15 feet at maximum and had planned on using pvc conduit and fittings. I'd like to run two sets of wires. One for a 30 amp generator inlet and one for a future sub panel in the garage. Garage is only large enough for one car so I only need a few circuits for lights, garage door opener and a few outlets. Won't be running a large compressor or welder so I was thinking a 60 amp sub panel should be more than sufficient with room to spare for a future home owner. Questions are:

1. I think I need to run 10/3 for the 30 amp which will have a total distance of about 60 feet from the main panel, through the 15 feet of conduit, inside the garage to the point it goes back out of the garage wall in the back to the generator inlet box. Is this correct and if so what type of wire should I use? FYI This will be connected to a 30 amp breaker in the main panel with an interlock kit.

2. What size wire and type should I use for the sub panel again with a distance of about 60 feet to go to where I'd like to place the sub panel?

3. What size conduit should I use to run both wires or do I need to run them in separate conduit? I'd prefer to run in one if possible for aesthetic reasons but will certainly do what is better from a safety standpoint?

4. Can I run one set of wires now for the generator and then run the other set later when I'm ready for the sub panel or is it necessary to run them all at once and just leave both ends disconnected and marked?

 

[rockwithjason]

Good questions.

10/3 is acceptable for 30a loads within 100ft or so of the panel. Longer runs may need up sizing.
6/3 would give you the 60a sub you are wanting
you can run romex in pvc but you will have to run much larger pipe to fit the cables in. I am guessing without running a calculation but I would say a 1 1/2 in pipe is close to what you would need. You can run the cables now and hook them up later but the ends must be in a jbox

 

[pattenp]

NM-b (Romex) is for interior use only. It can be in conduit inside, but not outside.

 

[jtd771]

NM-b (Romex) is for interior use only. It can be in conduit inside, but not outside.

Should I use THHN instead?

Sent from my Nexus 7 using Tapatalk 4

 

[wyliesdiesels]

I have a garage that although attached to the house there is no way to run wire from the main panel in the house to the garage without going outside. The distance along an exterior wall from where I would exit the house to the garage where it would enter is about 15 feet at maximum and had planned on using pvc conduit and fittings. I'd like to run two sets of wires. One for a 30 amp generator inlet and one for a future sub panel in the garage. Garage is only large enough for one car so I only need a few circuits for lights, garage door opener and a few outlets. Won't be running a large compressor or welder so I was thinking a 60 amp sub panel should be more than sufficient with room to spare for a future home owner. Questions are:

1. I think I need to run 10/3 for the 30 amp which will have a total distance of about 60 feet from the main panel, through the 15 feet of conduit, inside the garage to the point it goes back out of the garage wall in the back to the generator inlet box. Is this correct and if so what type of wire should I use? FYI This will be connected to a 30 amp breaker in the main panel with an interlock kit.

2. What size wire and type should I use for the sub panel again with a distance of about 60 feet to go to where I'd like to place the sub panel?

3. What size conduit should I use to run both wires or do I need to run them in separate conduit? I'd prefer to run in one if possible for aesthetic reasons but will certainly do what is better from a safety standpoint?

4. Can I run one set of wires now for the generator and then run the other set later when I'm ready for the sub panel or is it necessary to run them all at once and just leave both ends disconnected and marked?

1. 10/3 will work for the generator at that distance. But due to it being outside, u will need direct burial/wet rated UF-b, aka Romex, as already stated by 'pattenp'.

http://www.homedepot.com/p/Southwire-100-ft-10-3-UF-B-with-Gauge-Cable-Grey-13059123/202316273

2. The wire type and size depends on what size breaker you will be feeding it with. Since you wont have any big loads, 50-60a would be plenty, as suggested by 'rockwithjason'.

You will need this if ran outside:

http://www.homedepot.com/s/uf-b+6-3?NCNI-5

3. I would run them in separate conduits to make it easier in the future if the cable needs to be changed out.

Also, several issues also come up when running that many conductors in the same conduit:

1. Because you will have 4 current carrying conductors in the same raceway, the ampacity of each wire will have to be derated. This means upsizing the wire and more expense!
2. Due to the thickness of the outer jacket(1.1747"), you will need at least 1 1/2" PVC sch 40 just for the 6/3 UF-b, but i would go larger. And if there is any areas where the sch 40 could get damaged, then you will need sch 80 in those spots, so u have to go larger still.

Another alternative would be to use individual THHN conductors. The pull would be a lot easier and u could use smaller conduit. And, if u do decide to use THHN and run all 8 wires in the same conduit, the starting ampacity rating that u derate from for THHN starts at a much higher rating(90* c rating instead of 60* c for NM-b), so u wouldnt need to use wire larger than #10 and #6!

Conduit size for those 8 THHN conductors would be 1" but 1 1/4" would be easier. And u can use a #10 THHN for the ground wire for the 50-60a subpanel circuit!

4. You can run some wires now and some later but it will be easier to pull all at the same time. Either way, i would also pull a pull string through the conduit in case u need it later!