Installing driveway post lights this weekend,,any tips?

[sportbikerider78]

I already know how to go about it...if there are any pointers..that'd be great.

Going direct burial line...no pvc pipe except on exiting the house.
480' line and 3 posts with outlets. Only running LED post lights and Christmas lights off the pole outlets.
2' deep 1' wide post holes
Buying a post hole digger and 3 bags of quickcrete

One question...should I run the wiring right through the cement? Or should I run pvc in and out of the lightpole? I was thinking that if I ever had an issue with the wiring it would be impossible to remove if I poured it right into the post hole.

 

[peakbagger]

I believe that code requires that the wire be encased in conduit when its above ground. If its PVC it has to be Sch 80 if its exposed and I think it has to go down at least 18" (minimum depth to bury wire in most places). Generally you want some give in the conduit or wire so if there any frost movement it doesn't get pulled on. Make sure you bury some ribbon on top of the wire run after you have partially backfilled the trench so anyone digging in the future gets some warning.

 

[brenndatomu]

2' deep 1' wide post holes

Is that deep enough?
You need to get below the frost line and that is considered to be 36" here on NE OH...I would think it would be that much or more in Syracuse

 

[sportbikerider78]

From everything I have read, direct burial does not need to be below 24" and can be as little as 12". In everything I have also read, makes no mention of frost having a negative effect on the cable.

I am also going under a gravel driveway for a 20' part of the run. That will be in PVC at a depth of 24". Anywhere you have the potential of a disturbance or heavy load, it needs to be protected.

 

[brenndatomu]

In everything I have also read, makes no mention of frost having a negative effect on the cable.

If you are referring to what I said, I meant the posts...

 

[burnham]

*without looking in the book* Type UF has to be down 24" if it's direct buried. I cannot be encased in concrete, use conduit at the posts. If the UF wire is GFCI protected I think it can be down 12".

 

[gzecc]

Cement at 2' will heave in your climate. Do you really need cement? Go 3' and put mostly QP stone around the bottom.

 

[fbelec]

you need only to go down 2 feet. put 90 degree pvc in and out of the cement and pull a extra foot of cable out of the top of the post and bend it back down the post incase it moves but at 2 feet if the post is moving because of frost so is the wire. and if you haven't done it yet if the cable goes under a driveway that part has to be down 3 feet. i never use cement in the post hole because the posts will rot out sooner because of the lime in cement. i use a 8 by 8 by 8 cement block and stick the post thru that and use stones to level it off. after a couple of rain storms the ground around it will hold it tight enough. and doing it that way if it were to get hit be something car or branch it will fall but still be good enough to reinstall with out having to buy new. has worked for 25 years now

 

[Highbeam]

Yes, conduit will be on the post anyways to run the wire up to the light. That same conduit will go down the post to the required depth and then put a 90 on the bottom and even a short stub to be sure that the end of the PVC is out of the concrete. You might even have two conduits on the post. One in and one out to the next post. UF is thick, tough, and hard to stuff into conduit. You're digging the trench anyway, have you thought of running 100% conduit and pulling cheaper stranded wires? I really dislike stripping and working with the thick UF cable coating.

 

[sportbikerider78]

Thanks for the advice on not using concrete. I really hadn't thought of doing it any other way. Interesting...I'll research it more.

It was an absolute bear to dig one of the holes near my rock wall and a large ash tree. Tons of big roots and big rocks. Took me 1 hr to get down 2 feet.
I bought 1/2" gray pvc and 90 degree pre-bended elbows. One in and one out, is the plan. All the cable is <$190 for about 500'. I think it is just easier to not use conduit for the whole run.

 

[Highbeam]

1/2" conduit for uf cable??!! You're gonna have fun with that.

 

[greg13]

All the cable is <$190 for about 500'. I think it is just easier to not use conduit for the whole run.

Until you have a problem with the cable. It is easier to pull new cable through conduit than it is to re dig 480' of trench. Plus with conduit you do not have to go as deep since the wires are protected.

 

[sportbikerider78]

If I was going to stay in this house forever, I'd do some projects differently. The high taxes and cost of living in NY will not allow me to stay here forever.

I'm going to gamble and say that I will have zero issues with this cable sitting in the ground for 5-10 yrs.

Thank you for your input..that is why I posted this thread.

 

[Highbeam]

Seriously consider using larger conduit then. UF is a fat cable. Just try feeding it into the conduit before you commit. I would be using one inch.

When you backfill the trench, pay attention to the material to avoid rocks on the cable.

 

[mass_burner]

Until you have a problem with the cable. It is easier to pull new cable through conduit than it is to re dig 480' of trench. Plus with conduit you do not have to go as deep since the wires are protected.

Since this is just outdoor post lights, I can see why he wants to omit conduit. I just went through this with electrical service and the conduit was a life saver.

 

[semipro]

If you do direct -bury the cable please consider installing some warning ribbon in the trench above it also.

 

[sportbikerider78]

Ok...it was a rough weekend with weather and lots of work was accomplished with the help of an equally hard working friend.

I decided to go with 12/3 wire so that I could keep the outlets at each pole separate from the power to the post light itself. This is so I can have Christmas lights on wrapped around the posts, and not have the post lights on themselves. They came out nice and all that is left to do is to fill the trenches back in and tap down. I used a short run of cpvc and 90 degree angle in and out of the pole base. I did this to keep the wire out of the cement.
I used rocks to stabilize the pole and keep it level, then poured half a bag of quikcrete in on top of the rocks. This filled the hole about half way. The rest we packed with clay soil.

I'm very happy with how it came out. Wife and I walked around last night up our driveway, for the first time without flashlights.

 

[fbelec]

looks great. remember to gfi the circuit so you can plug in lights and not worry about bad wires. don't want have a problem with people or a dog getting zapped.

 

[sportbikerider78]

Will do.

 

[Highbeam]

looks great. remember to gfi the circuit so you can plug in lights and not worry about bad wires. don't want have a problem with people or a dog getting zapped.

We had a lot of street lights lose their ground or neutral or whatever and become energized. Dogs would get zapped when peeing on the poles!

 

[fbelec]

we had a few in boston walk across a man hole and die. nasty way to go

 

[gzecc]

We had a lot of street lights lose their ground or neutral or whatever and become energized. Dogs would get zapped when peeing on the poles!

I watched an episode of Myth Busters. A person urinating on a live 3rd rail did not get electrocuted. Very surprising to everyone.

 

[Highbeam]

I watched an episode of Myth Busters. A person urinating on a live 3rd rail did not get electrocuted. Very surprising to everyone.

But was the guy barefoot with wet paws? It was a big deal in the news and for the municipal community since the cities are responsible. We don't have these electrified rails in the PNW so I have no idea at what voltage they run.

 

[semipro]

I watched an episode of Myth Busters. A person urinating on a live 3rd rail did not get electrocuted. Very surprising to everyone.

I don't think the stream is continuous. It very quickly transforms from a continuous stream to discrete droplets -- so no continuous path for current flow.