I was going to say the same thing as well but just try that over in France we have to use the AMFO to blast few rocks out ( I manged to tick few peoples off ) but it was not that bad compared what you are going thru.This has got to be the craziest job i've seen in a long time.
Marc, I feel very lucky that in only 3 cases I had to go slightly shallow with the trench to go over top of rock that was too large to get out. I still have about 200' of trench to dig so hopefully I won't run into any more.but just try that over in France we have to use the ANFO to blast few rocks out
When I was a first year apprentice I was working on a job where we laid thousands of feet of PVC conduit (4"-6") in the ground and buried them in concrete. My foreman told me to get into the trench and step on the conduits that were floating after the concrete had been poured on top. I figured I'd vibrate the conduits down with my feet.A bag of Sakrete comes in handy to hold the conduit down in the bed because they want to float up in the water.
The wires will be tied together in an 8X8X4 inch box but I’m not sure what kind of fittings are available to enter the box with. The conduits will also get a lot of heat from the sun and I’m wondering if I should use some sort of sliding joint, like maybe an unglued bell? The grey plastic boxes I found at the big box stores are not very impressive quality wise but should work. Does anyone have any suggestions for a higher quality box?
Go to the Hoffman website and check out what they have. Then talk to a local supplier who knows underground. Where your phone conduits come up, you may need a pedestal large enough to set a terminal box. Depending on the situation, the phone company here will install the pedestal, at your cots on your property, at theirs on public property.Any help here? This is the first time I have worked with conduit and outdoor boxes. I apprenticed for two years doing nothing but underground. Because of that, it seemed I was the go-to girl for underground projects for much of my career, which eventually led to project managing an underground division of a large EC here. I learned a lot in the process BUT, the last UG project I did was in 2005 so products may have come along since then that I don't know about. I'll do my best to answer your questions.
1) Metal or plastic boxes? My top concern is keeping moisture and bugs out. I would like to do this once and not worry about replacing a cracked or rusted box in the future.
I like the fact that PVC doesn't rust and that comes in really handy when you're pulling through underground conduit, especially old stuff. As far as boxes, I'd probably go with metal so long as the finish on it is decent and it's NEMA 3R approved.
Moisture is a ***** to keep out, so are bugs. But I have seen more problems with moisture in metal boxes than in PVC boxes, especially the ones using properly glued slip joints. (But I'm talking buried boxes here.) Make sure you use a gasket on the inside of the box under the locknut on the PVC connectors if you go PVC.
BTW, I have a metal box I installed in 1993 to split up the AC disconnect and hot tub panel on the back of my house. It has a nice thick rubber gasket all around the cover. When I opened it this summer, water came pouring out. The conduit inlets are all from the sides and back and all have thin gaskets on the outside. I also found a few spiders in there too.
2) Should I be concerned about the conduit expanding and contracting and use some sort of slip joint? The conduits receive direct sunlight for most of the year and they are out of the ground about 30".
I prefer slip joints over compression for PVC. Just make sure you clean it well with primer before applying glue. As far as the sunlight, check with the manufacturer. Some PVC is not UV resistant.
3) Any worries about UV on the phone conduits or box? My other power sweep which was installed last year is turning almost white on the side towards the sun.
See above. Code around here requires all conduits exiting the ground to be metallic, GRC or IMC. In some areas, you can use PVC for phone conduits.
4) Is there a standard connector that goes from the conduit to a box? (see conduit pic above)
Use slip joints with gaskets on the threaded half and glue well. Compression fittings label themselves "raintite". There's a reason you don't come into the top of an outdoor box with a conduit - water seeps into anything it can. In the JB on the outside of my house, once I saw the water, I drilled holes into the bottom. If I had conduits coming out the bottom, the water would have probably seeped out there. Nothing is perfect.
Here is the box I was planning on using but I saw it in the store and it seems a bit cheesy.
If you're going to use that box for the conduits in the picture and mount it with the cover vertical, you may have problems with the angles on the sides of the box. If I'm seeing the box right, that's the kind of box that has sides that are less than 90 degrees in relation to the top and bottom. They are designed to bring conduits into the bottom. Bringing conduits into the sides will invite moisture into the box.
Here is a metal box but it doesn't show how it opens or seals.
What you're looking at in the picture is the top of the box. The cover is fastened on the bottom with a screw and slides away at the bottom to remove it from the overhang at the top. That box is about as raintite as you need and if the paint never chips or gets dinged will probably do just fine.
I'm very grateful for your time and information Julie!! I will check out the Hoffman site and I believe you have persuaded me to go with a metal box. The demarc is 500' away back at the power pole so I'm just using this box to splice the already pulled phone wires together.Go to the Hoffman website and check out what they have. Then talk to a local supplier who knows underground. Where your phone conduits come up, you may need a pedestal large enough to set a terminal box. Depending on the situation, the phone company here will install the pedestal, at your cots on your property, at theirs on public property.
All electrical boxes should be 10x the size of the largest conduit unless it's a straight pull through, then it's 8x. As far as metal vs. PVC on boxes, metal is conductive but rusts, PVC doesn't rust but is not conductive. But PVC can break down under UV unless it's properly treated.
Don't take this as gospel. I'm sure there are other opinions. This has just been my experience.
Hey! good to see you are still around Julie. I will keep an eye on the water. The splices were upside down and dangling on the bottom so I twisted them around the cable to keep them higher.Wow! Still at it! This is like a regular job. :laughing: Nice work! :thumbup:
You might want to check back in the spring and see if your box has taken on any water. PVC boxes have a tendency to change shape with the weather. If so, you can always drill a drain hole.