Anatomy of wiring through my house's sill
#1
Member
Thread Starter
Join Date: May 2017
Posts: 3
Upvotes: 0
Received 0 Upvotes
on
0 Posts
Anatomy of wiring through my house's sill
Hi All,
I'm working on the planning phase for running power from my basement to my backyard shed. I am new to town and want to impress/befriend my inspector so I'm hoping to get some verification of my plan which is a compilation of several different online diy tutorials, which may have provided more confusion than clarity.
1. My main question is around running the cable (in this case, 12-2 UF protected by a 20 amp GFCI breaker) through the sill of my house to the outside world. Once I've drilled a hole through the sill, can the UF cable go through it bare or does it have to be in conduit? Directly on the opposite (outside) wall I plan on lining up knockout on the back of a 1 gang metal outdoor electrical box. In that box, do I need to separate the UF cable and make a new connection, or if I'm running the same cable, can I skip the box and continue into the conduit run? (In some how-tos it is stated that the reason for the box is to have access to the connections outdoors, I think that assumes a standard 12 gauge cable inside is being connected to the UF cable outside.) Essentially, what should this look like?
2. I've read in certain books/articles that there is a limit to the number of turns a cable can take. Is this just in one run? In other words, if I put an outlet in between where it comes out of the sill, and goes into the shed, will that "reset" the sum of angles I'm allowed?
3. Just want to confirm that for UF cable, GFCI protected, in 1/2" non-metallic (PVC) conduit, my trench only needs to be 12"? Table 300.5 is a little hard to read. It almost looks like I don't need the conduit underground if the UF cable is GFCI protected.
Your help is much appreciated and will go a long way to getting on the good side of my inspector who is already notorious for not liking homeowners doing their own work.
I'm working on the planning phase for running power from my basement to my backyard shed. I am new to town and want to impress/befriend my inspector so I'm hoping to get some verification of my plan which is a compilation of several different online diy tutorials, which may have provided more confusion than clarity.
1. My main question is around running the cable (in this case, 12-2 UF protected by a 20 amp GFCI breaker) through the sill of my house to the outside world. Once I've drilled a hole through the sill, can the UF cable go through it bare or does it have to be in conduit? Directly on the opposite (outside) wall I plan on lining up knockout on the back of a 1 gang metal outdoor electrical box. In that box, do I need to separate the UF cable and make a new connection, or if I'm running the same cable, can I skip the box and continue into the conduit run? (In some how-tos it is stated that the reason for the box is to have access to the connections outdoors, I think that assumes a standard 12 gauge cable inside is being connected to the UF cable outside.) Essentially, what should this look like?
2. I've read in certain books/articles that there is a limit to the number of turns a cable can take. Is this just in one run? In other words, if I put an outlet in between where it comes out of the sill, and goes into the shed, will that "reset" the sum of angles I'm allowed?
3. Just want to confirm that for UF cable, GFCI protected, in 1/2" non-metallic (PVC) conduit, my trench only needs to be 12"? Table 300.5 is a little hard to read. It almost looks like I don't need the conduit underground if the UF cable is GFCI protected.
Your help is much appreciated and will go a long way to getting on the good side of my inspector who is already notorious for not liking homeowners doing their own work.
#2
Member
can the UF cable go through it bare or does it have to be in conduit?
do I need to separate the UF cable and make a new connection, or if I'm running the same cable, can I skip the box and continue into the conduit run
You may also choose to run 12-2 NM-B up to the exterior junction box, then splice UF or THWN from that point. THWN will be easier to work with than UF.
there is a limit to the number of turns a cable can take
Just want to confirm that for UF cable, GFCI protected, in 1/2" non-metallic (PVC) conduit, my trench only needs to be 12"?
#3
Question 1: If you use UF no box but it does need to be protected by PVC conduit till it enters the ground so you can use a pull elbow outside and a short piece of PVC into the ground. If you use UF cable it is best to direct bury. It can be hard to pull in conduit.
Question 2:
That refers to conduit not cable.
Question 3:
Yes, but I wouldn't run it in conduit. Just use for a protective sleeve where it enters and leaves the ground.
If you want to use conduit use individual conductors such as THWN in conduit. In this case you could use a box outside at the house. Run NM-b inside and into the back of the box and then convert to THWN.
While you can use cable in conduit all the way it is harder to pull and there is no need if the conduit is continuous all the way. Use 1" conduit and you will be future proofed should you ever need more power at the garage.
You will also need a disconnect at the shed. A 20 amp light switch is okay for this.
Question 2:
there is a limit to the number of turns a cable can take.
Question 3:
Just want to confirm that for UF cable, GFCI protected, in 1/2" non-metallic (PVC) conduit, my trench only needs to be 12"?
If you want to use conduit use individual conductors such as THWN in conduit. In this case you could use a box outside at the house. Run NM-b inside and into the back of the box and then convert to THWN.
While you can use cable in conduit all the way it is harder to pull and there is no need if the conduit is continuous all the way. Use 1" conduit and you will be future proofed should you ever need more power at the garage.
You will also need a disconnect at the shed. A 20 amp light switch is okay for this.
#4
Member
If you use UF cable it is best to direct bury.
Chances are one day someone will put a shovel in the ground and damage the cable.
Conduit and THWN is the best solution for me.
#6
Member
Thread Starter
Join Date: May 2017
Posts: 3
Upvotes: 0
Received 0 Upvotes
on
0 Posts
And non-metallic 1/2" PVC conduit would be sufficient in the event of a shovel? (Of course a layer of sand and warning tape will be on top of it)
Last edited by samd1223; 05-25-17 at 09:31 AM. Reason: Adding 1/2" PVC
#7
If you use individual conductors yes. If you persist in using UF I'd suggest at least ¾" to make pulling easier.
Maybe?
And non-metallic 1/2" PVC conduit would be sufficient in the event of a shovel?
#8
Standard schedule 40 PVC is just fine against the standard array of household human-powered yard tools. It does not provide much resistance to power equipment. You can always go schedule 80 PVC for additional protection, but it may be a special order item in smaller sizes.
#9
Member
And non-metallic 1/2" PVC conduit would be sufficient in the event of a shovel? (Of course a layer of sand and warning tape will be on top of it)
What good will sand and warning tape do at 12"? Shovel can go that deep when you just stick it in the ground and step on it.
#12
Member
Join Date: Nov 2007
Posts: 295
Upvotes: 0
Received 0 Upvotes
on
0 Posts
There are no limit to the number of turns a cable can take. However, there are limit to the number of turns in conduit before needing a pull access (junction box, pull elbow, LB fitting, etc..). I don't remember the limit
#13
Member
Thread Starter
Join Date: May 2017
Posts: 3
Upvotes: 0
Received 0 Upvotes
on
0 Posts
No UF in PVC conduit?
Hi all,
Thank you very much for your help. After pulling UF wire through the conduit I was very pleased to be done. It was a HUGE pain. I went to my inspector to just run a few questions by him, and he told me I can't run UF in PVC conduit. "It's a different kind of wiring." He said I needed to use individual conductor wire instead. What do you guys think?
Thanks,
Sam
Thank you very much for your help. After pulling UF wire through the conduit I was very pleased to be done. It was a HUGE pain. I went to my inspector to just run a few questions by him, and he told me I can't run UF in PVC conduit. "It's a different kind of wiring." He said I needed to use individual conductor wire instead. What do you guys think?
Thanks,
Sam
#14
Your inspector needs to read the codebook . It is even required to protect cables against physical damage.