PVC Conduit crossing main line from street

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Old 03-04-18, 07:26 AM
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PVC Conduit crossing main line from street

I have this issue now where I need to somehow cross my main powerline perpendicular. I can either slide my conduit under it or I can ise flexible consuit and go over it. There is about 3/4 space under it and conduit I m running is 1/2. There is also a large PVC pipe next to the main that is my radon pipe. How should I do this?

Another question is, can PVC conduit be ziptied to gutter pipe running vertical for a section of 2-3 or so? I have multi level roof and there is a spot where I need to transition to the higher roof. I dont want to connect the conduit to brick siding as its too hard not to damage it but simply run the pvc alongside of the gutters.
 
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Old 03-05-18, 04:04 AM
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Bump, after doing some more careful thinking, I think its better I use a heatgun to flex the pvc and go over both the radon and mainline. The question is though for that portion of pvc that is not contacting anything which will be probably 2-3” away from the side of the house, is it okay if its not secured to anything? Or can I use one of those threaded rods plumbers use, cut it in special length and sort of have a trapeze like clamp?

Also I was doing some reading, and looks like because where I live temperature can fluctuate more than 100F, which translates into 1/4” of change every 6’, I need to use those expansion joint things in a lot of places including verticals. Is that really necessary or overkill? Actually my light fixture boxes will be in evey 6-8 feet so I m right at the border of that number.
 
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Old 03-05-18, 06:48 AM
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You could go over or under with the conduit. It doesn't really matter from an electrical point of view, just how you to install it and how you want it to look. If I was doing it, I'd probably go under since it's only 1/2" pipe. PVC conduit needs a mounting strap every 3 feet, so as long as you meet that no additional fastening is required on the saddle bend.

It's not the best to use zip ties outdoors as they break down in the UV sunlight. If you need flexible ties use something like galvanized wire.

At 6-8' lengths I would not install expansion joints.
 
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Old 03-05-18, 08:59 AM
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I would consider using EMT. Electrically, it's all the same, but PVC tends to droop and look cruddy.

If you do decide to bend and offset it from the house, you can use threaded rod, or you can use unistrut. It can be a bit pricey, but you'll only need a few mounting points.
 
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Old 03-05-18, 03:11 PM
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Using EMT would be too hard for me to do. I am installing 4 cameras/floodlights, 2 on the front, 1 on the side, and 1 out in the back. Lots of turns and straight runs, I suspect about 100 feet total. PVC is the only thing I can use.

I also decided to go over the main line because while its possible to slide a pvc pipe under the mainline, making it turn towards the roof without either a kink on the pipe OR putting pressure on main power line is impossible.

I know you are saying extension joint isnt necessary but considering how much money and time I am investing, is it worth the risk? Is there a downside using them? I think the easiest thing to do is to use one right next to each light fixture box, right? I probably need 4-5 of them.
 
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Old 03-06-18, 05:01 AM
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WHat do you guys think regarding this non metallic liquidtight flexible conduit? Its a bit more expensive but it seems easier to deal with?

https://www.homedepot.com/p/AFC-Cabl...0-00/202286688
 
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Old 03-06-18, 07:02 AM
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Liquidtight is OK too -- more expensive, but it's pretty easy to work with. You have to use a lot of mounting straps or it will sag.

If you don't use expansion joints on PVC it can crack or bend out of shape a bit. The downside is that the expansion joints are expensive and ugly if in an exposed area. I'd just leave the box mounting screws a little loose so it can move around to allow expansion.
 
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Old 03-06-18, 07:18 AM
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Originally Posted by ibpooks View Post
Liquidtight is OK too -- more expensive, but it's pretty easy to work with. You have to use a lot of mounting straps or it will sag.

If you don't use expansion joints on PVC it can crack or bend out of shape a bit. The downside is that the expansion joints are expensive and ugly if in an exposed area. I'd just leave the box mounting screws a little loose so it can move around to allow expansion.
Hmm, i just measured some of the straights and my original estimate of 6-8 seems to be rather off Its going to be around 10-12 feet between each 90 degree bend or electrical box. I suspect I need to use these things. I also think even if I ise liquidtight this same problem happens and I need expansion joints. Lastly in straight runs that are as long as mine, probably that flexible liquid tight pipe isnt going to look very good so pvc is better.

If I use those expansion joints, can i use them right after 90 degree bends rather than by the box? Because if I use them by the 90 degree bends they will be on the far corners of the house by the gutters vs the light fixture box is right in the middle.
 
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Old 03-06-18, 07:33 AM
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You don't have to use expansions between 90 bends as the pipe can flex a bit in the corner. You only need them between securely mounted points.

Liquidtight is flexible enough that it does not require expansion joints. It will easily move by itself.
 
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Old 03-06-18, 10:25 AM
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Originally Posted by ibpooks View Post
You don't have to use expansions between 90 bends as the pipe can flex a bit in the corner. You only need them between securely mounted points.

Liquidtight is flexible enough that it does not require expansion joints. It will easily move by itself.
I see, so the only time expansion joint is used is both sides of any given straight run is solidly mounted box? If thats the case then I never have to use them because I will never have a case where this is true.

I am also looking into this liquidtight stuff, my only concern is if I can make this stuff straight enough so it doesnt look bad. I would probably need to buy a 100ft roll.
 
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