UNDERGROUND ELEC – Steel to plastic??
Folks,
Anyone have a working method for connecting rotted out 1/2″ rigid conduit to P40? The steel seems to be rotting out at the sweeps up to the boxes. Bending stress? Was removing a dead one and the good side went too. The lamp post also rotted out, so it was a perfect day. Had to pull the stump and set a new one.
LOL – this lamp post is in aluminum instead of a steel tube the thickness of an old beer can. However, sez on the box – guaranteed not to rust. I am so reassured. Aluminum? Get real!
I am left with a jagged conduit end down in a hole and wires that look better in the conduit than they do at the box where there is serious galvanic corrosion.
Thoughts include irrigation repair sleeve to P 40 conduit or 3/4 P40 sleeve with caulk, perhaps split end and hose clamp run over the conduit to the first rust nodule, then bush down to 1/2 P40.
Got more rotted lamp posts, so I think I am going to see more of this.
(Could be worse – poor HO down the way has had the plumbers ($$$) for some days jack hammering her slab up, trying to find some cast iron DWV that was not all holes. The lawn is a mound of dirt.)
The ToolBear
“Never met a man who couldn’t teach me something.” Anon.
Replies
What about the conduit you can't see? Isn't there a good chance it's shot, too?
But anyway, I think the right approach would be to excavate until you find sound conduit and them use a compression MA fitting on the rigid to a coupling, to an MA on the sched 40 or 80. I recently had to buy a couple of steel compression MAs for 3/4" rigid (because I didn't want to mess around cutting threads on the stub), $7 apiece for the MA fitting.
Good luck,
Cliff
@@ What about the conduit you can't see? Isn't there a good chance it's shot, too?
Above average, I would say. <g>
Nodules of rust on what I can see. Stuff is going. However, I hotwired the leg to the far lamp post and got a light. Did a continunity check and got Open Line, so the wire appears "clean". When there is trouble in the wire, I get rising resistance on the meter peaking who knows where. I don't wait much beyond 400 ohms.
A sample from the leg we just replaced was looking good. It would appear that the serious galvanic corrosion is happening in the boxes - right where the wire exits. On this job, the wires were eaten out and broken at the exit. The box up the line has them cemented in with corrosion.
I considered potting my work in silicone at that point, but didn't know how it would react to the insulation, so I bought some wiring harness loom that I can use to protect the wires as they enter the box. The ToolBear
"Never met a man who couldn't teach me something." Anon.
use a no thread male adaptor...
attach a p40 female adaptor to that...
plastic on...
Life is not a journey to the grave with the intention of arriving safely in a pretty and well preserved body, but rather to skid in broadside, thoroughly used up, totally worn out, and loudly proclaiming
WOW!!! What a Ride!
Forget the primal scream, just ROAR!!!
It's Friday and I am in my end of week Duh? Bear mode.
No thread male adapter?
Got plenty with thread on one end and slip socket for PVC and glue on other.
Same thing? If not, what does it look like?
I removed the liquidtight plus hose clamp and used a 1/2" repair coupling - has gaskets and compression connections on each end. Snugged down well on both ends. Of course, it's the wrong color - but made a nice connection.
The ToolBear
"Never met a man who couldn't teach me something." Anon.
Okay...
so use a No thread female adaptor and do the sequence in reverse...Life is not a journey to the grave with the intention of arriving safely in a pretty and well preserved body, but rather to skid in broadside, thoroughly used up, totally worn out, and loudly proclaiming<!----><!----><!---->
WOW!!! What a Ride!<!----><!---->
Forget the primal scream, just ROAR!!!
looks like a compression fitting for EMT only larger and it fits rigid pipe...
the better ones have a compression ring and a compression collar...Life is not a journey to the grave with the intention of arriving safely in a pretty and well preserved body, but rather to skid in broadside, thoroughly used up, totally worn out, and loudly proclaiming<!----><!----><!---->
WOW!!! What a Ride!<!----><!---->
Forget the primal scream, just ROAR!!!
Looked in my old Hubbell/Raco catalog and found rigid compression fittings.
That what you had in mind?The ToolBear
"Never met a man who couldn't teach me something." Anon.
yup...Life is not a journey to the grave with the intention of arriving safely in a pretty and well preserved body, but rather to skid in broadside, thoroughly used up, totally worn out, and loudly proclaiming<!----><!----><!---->
WOW!!! What a Ride!<!----><!---->
Forget the primal scream, just ROAR!!!
Clean up the steel conduit a bit. Eliminate any sharp edges or at least roll them toward the outside of the pipe where they won't threaten the insulation on the wires. Slipping on a length of tubing, heat shrink will work but no need to actually shrink it, over the wires where the steel ends may help but isn't vital. If the wires will slide out easily a wrap or two of tape will do as well.
Go one size, or more if needed, up on the PVC conduit trade size and simply sleeve over the steel. Overlap for a foot or so at least. No need to go wild. No need to seal anything. Run this slightly over-sized PVC up to your box. Continue on with the 1/2" PVC coming out of the box.
Set the post firmly and bury the lot and your good. Don't worry about the rest of the steel conduit rusting. It happens and the circuits contained will likely, as long as they are not disturbed, remain good for decades. Sleeping dogs.
Underground conduits are Not designed to be watertight they are, by code, designated as a "wet location" and the wires pulled in are required to have an insulation on them that is compatible with being immersed in water 24/7/365. So there is no need to seal them or worry tremendously about water getting in. In fact there are cases where gaps or leaks can be beneficial. Mostly for letting water out.
Don't worry too much about the PVC sleeved over the steel. You sleeve it enough to maintain rough alignment and let the ground stabilize the joint. If filled and packed a bit movement should be insignificant.
@@ Slipping on a length of tubing, heat shrink will work but no need to actually shrink it, over the wires where the steel ends may help but isn't vital. If the wires will slide out easily a wrap or two of tape will do as well.
I slid some PEX I use for squaring up canted outlets over the wires to protect them from the edges. Got the rust off that section of wire and the repair coupling went on well and snugged up. Bought some wire harness loom for use at the boxes until I can find 3/4" red hats.
My other option, as you noted, was to go up one size. However, that meant changing the box up, the other fittings, etc. I have the 3/4 box at hand, but, happily this worked out well. I am sorting though my options to develop a workable fix, so the ice box light comes on at intervals.
Thinking of it, I could bush it down to 1/2 and hide the bushing underground. Might do that next time round. Less expense in fittings that way. With the repair coupling I was able to work with four inches of exposed pipe, half of which had a large rust nodule.
It was interesting that the underground wire was in fine shape. The galvanic corrosion is mostly in the boxes. Steel, Alum., Copper, salt air with acid. Sounds like a battery. I woud consider plastic boxes, but they all have ears for securing to some sort of backer. Trying to tell us something? The ToolBear
"Never met a man who couldn't teach me something." Anon.
Undergound... under water splices
As the wiring issues are at the boxes, I am wondering about some sort of waterproof splice repair. Need to go digging in the code for this topic. Any experiences?
If the bends are rotted - and most I have seen are or will be, complete the job, add a box or container for waterproof line splices and run fresh wire up to the boxes. As it is now, I have one fresh run of wire and two rather battered sets in a new box.
We were using direct burial nuts on one project. Wet winter. Water table was above ground level. I had to buy a bilge pump to dewater my pull boxes and holes long enought to work. Like to see how the nuts look in 5 years. Saw enought common nuts under 6" of water (with charring inside).
Could WP a Western Union splice the traditional way - with the three layers of tapes.
The ToolBear
"Never met a man who couldn't teach me something." Anon.