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Setting a granite lamp post

Shingle_Style's picture

Setting a granite lamp post (post #207065)

Shingle_Style on Sun, 11/11/2012 - 17:22
in

I am installing a string of three granite lamp posts to replace an existing string of wooden posts.  The posts are cored.  Should I try to snake the existing wires through the hole, which will probably require a splice inside the post, or should I try to install an LB on the side of the post.  If the later, how can I drill the post without cracking it?  If the former, how can I avoid pinching or crushing the wire when the 400 pound post drops in the hole?

-A +A

It normally would not be (post #207065, reply #1 of 9)

by DanH in reply to Shingle_Style [original] on Sun, 11/11/2012 - 18:16

It normally would not be legit to splice the wire inside the post (though it's not clear why you should need to do so, with or without an LB).

Does the supplier of the post give any hints as to how the wiring is normally handled?  (At the very least code would require a "bushing" where the wire exits the post.)

(If it were me I'd probably install a flush-buried junction box and run the individual wires to that, rather than daisy-chaining.)


Of all the preposterous assumptions of humanity over humanity, nothing exceeds most of the criticisms made on the habits of the poor by the well-housed, well-warmed, and well-fed.  --Herman Melville

The supplier doesn’t (post #207065, reply #2 of 9)

by Shingle_Style in reply to DanH [original] on Sun, 11/11/2012 - 19:02

The supplier doesn’t offer any advice on it. I was wondering about putting a junction box under the post too. As long as the box doesn’t support the weight, I suppose PVC would work?

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No, not a box under the post (post #207065, reply #3 of 9)

by DanH in reply to Shingle_Style [original] on Sun, 11/11/2012 - 19:46

No, not a box under the post (which wouldn't be legit for a junction box), but a flush-with-the-surface landscape lighting box.


Of all the preposterous assumptions of humanity over humanity, nothing exceeds most of the criticisms made on the habits of the poor by the well-housed, well-warmed, and well-fed.  --Herman Melville

That would avoid the problem (post #207065, reply #4 of 9)

by Shingle_Style in reply to DanH [original] on Sun, 11/11/2012 - 20:35

That would avoid the problem of having to drill the granite at the expense of visible box covers.  Any idea if a hammer drill with a 3/4" bit would break the post?

Try it and find out. In my (post #207065, reply #5 of 9)

by DanH in reply to Shingle_Style [original] on Sun, 11/11/2012 - 21:14

Try it and find out.

In my opinion the posts should be set on a base that contains a passageway for the wire, so that the weight of the post is not on the wire.  (And a bushing still needs to be placed in the post opening.)

The intent of the separate buried box was to allow the posts to be wired without daisy chaining and without having to "home run" each cable.  (And without having to attach boxes to the sides of the posts.) You can do it without the box, but you have to use one of the other schemes


Of all the preposterous assumptions of humanity over humanity, nothing exceeds most of the criticisms made on the habits of the poor by the well-housed, well-warmed, and well-fed.  --Herman Melville

Not sure I see the point of (post #207065, reply #9 of 9)

by DanH in reply to Shingle_Style [original] on Fri, 11/16/2012 - 21:12

Not sure I see the point of drilling the post.


Of all the preposterous assumptions of humanity over humanity, nothing exceeds most of the criticisms made on the habits of the poor by the well-housed, well-warmed, and well-fed.  --Herman Melville

Yes hammer drills crack (post #207065, reply #6 of 9)

by IdahoDon in reply to DanH [original] on Thu, 11/15/2012 - 23:57

Yes hammer drills crack granite!  lol   

Simply get a diamond core drill bit at lowes for $20  These cut a cylinder which can be broken off if you need to go deeper.

 

Beer was created so carpenters wouldn't rule the world.

I asked specifically about (post #207065, reply #7 of 9)

by Shingle_Style in reply to IdahoDon [original] on Fri, 11/16/2012 - 16:17

I asked specifically about the post because I have used hammer drills on granite slabs with no problems.  The core hole in the post is what makes it tricky.  I have also used diamond core bits on granite, but have found that they clog very quickly (but I was using 1/4").  Have you used 3/4" with success?

Yes, a good core drill goes (post #207065, reply #8 of 9)

by IdahoDon in reply to Shingle_Style [original] on Fri, 11/16/2012 - 20:42

Yes, a good core drill goes through pretty quickly.  If you are going deeper than the core will allow I just break the plug out with a hammer and punch of some kind and keep drilling.

I do know cheap core drills don't cut as fast as a good one.

 

Beer was created so carpenters wouldn't rule the world.