Question about Unistrut

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Lock Nut

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Our company is redoing some old existing services in a trailer lot. About constructing uprights for the outdoor panel (from POCO's meter base, feeding the indoor breaker panel) would it be against code to drive unistrut into the ground and attach/build the panel onto that? It shouldn't rust or anything right? So far most of the lots have had a concrete slab and we've been using unistrut shoes, but we have some coming up next week that do not because the meter base is further detached from the trailer and located near the woodline
 
Code would be silent on this issue since its more of a design issue. The manufacture will be a good resource here. I don't see them allowing direct contact with soil so your best bet may be pressure treated 4 x 4 posts or equivalent.
 
Lock Nut said:
Our company is redoing some old existing services in a trailer lot. About constructing uprights for the outdoor panel (from POCO's meter base, feeding the indoor breaker panel) would it be against code to drive unistrut into the ground and attach/build the panel onto that? It shouldn't rust or anything right? So far most of the lots have had a concrete slab and we've been using unistrut shoes, but we have some coming up next week that do not because the meter base is further detached from the trailer and located near the woodline
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Why not use metal fence posts? they are made to be pounded into the ground. I think you can get some 6" tall ones for $10 or so.
 
We do a LOT of outdoor services for ag.

When we use strut verticals or 3" galvanized pipe for legs, we sakrete them in. Every time.

When we do 6x6 PT posts, we don't sakrete them in.
 
Cow said:
We do a LOT of outdoor services for ag.

When we use strut verticals or 3" galvanized pipe for legs, we sakrete them in. Every time.

When we do 6x6 PT posts, we don't sakrete them in.
Click to expand...

The other electrician who's on this project doesn't really care for the route using quickcrete. I'd suggested that, but he didn't like it. I was kinda for hammering the unistrut uprights while keeping them level and in plane with the other one. He wasn't sure if that would be frowned upon or not. The inspector that usually comes out is well known around these parts for being a guy that will go out of his way to point out any/every little thing he doesn't like.

So far, he's failed us for one of the panels being two inches short of the (supposedly) required 24" clearance off of the ground, as well as using self-tapping screws instead of nut/bolt/washer. I saw that one coming, the tech-screws' "anti-rust" zinc coating is damaged once it goes through the metal backing on the panel. The panel will be loose in 6-8 years, I wish goober head would have listened to me.

Funny, we haven't had even ONE single failed inspection or any issue whatsoever with any of the other inspectors. Just our luck I suppose... -_- I did like the suggestion about using the metal fence posts however, might give that one a go!
 
When Ive used unistrut I build the rack first.. post hole diggers and drop rack in. Plum, level, square and we ready to go.
 
If the strut isn't SS or coated, it will rust at/under ground level.
I usually use either 4x4 or 6x6 for the posts and use strut from post to post.
 
Lock Nut said:
Our company is redoing some old existing services in a trailer lot. About constructing uprights for the outdoor panel (from POCO's meter base, feeding the indoor breaker panel) would it be against code to drive unistrut into the ground and attach/build the panel onto that? It shouldn't rust or anything right? So far most of the lots have had a concrete slab and we've been using unistrut shoes, but we have some coming up next week that do not because the meter base is further detached from the trailer and located near the woodline
Click to expand...

not for something permanent. it'll rust at ground level
in a couple years.

when i've needed something for a short while, i use a hilti
demo hammer with a ground rod driver to drive strut in.
depending on the ground, up to 2' or better in. put the
corner of the strut on the ground rod driver, and it'll spall
and make a spot to keep the hammer from slipping off.

really hard ground will beat the end of the strut up pretty
badly. cut off the destroyed part at the height you want it
once you get it solid.
 
I would not trust unistrut in the ground to support a service. We do drive unistrut in the ground when we need to support a temp pole but that is usually only there for a year or so. The strut is just used to support the wooden brace to the temp pole
 
Cow said:
We do a LOT of outdoor services for ag.

When we use strut verticals or 3" galvanized pipe for legs, we sakrete them in. Every time.

When we do 6x6 PT posts, we don't sakrete them in.
Click to expand...

I mostly do same thing you mentioned.

Treated lumber still rots away after time, it just takes longer then non treated lumber.

Soil conditions will determine how well metal objects will stand up. Top few inches of soil is where worst corrosion activity will occurr, if anything coat it with some auto body undercoating or similar product where is it will be in direct earth contact. Regular galvanized strut holds up pretty well in most conditions though.
 
Our POCO requires Galv Strut and a 3x3 conc pad.

What I do is
Prefab the meter/panel onto 10 ft long back to back HD strut

We have the backhole dig a 5 ft deep trench

Take two sono tubes 2 feet long, put over the unistrut, put into the 5 ft deep trench. plumb and backfill to top of sonotubes. we brace the rack with some emt
Fill sono tubes with a mix of 30 min set grout and readymix. then fill to 2 ft below grade.
Now your strut rack is secure, and can ditch out from it, and connect to panel
When all UG conduit is done and inspected, backfill and pour the pad around the meter/panel.

Advantage is we have a stable rack when running conduits up to the meter/panel.

We build our equipment for a service life of 30+ years.
 
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