Conduit Straps being welded

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lizzie14

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Is it acceptable to weld conduit straps to the wall? Working in a prison here, and they want to weld for security. I found 300.18 (B) and it doesn't appear that this is legal. Any input?
 
In my opinion you can weld the strap to the wall as long as you do not weld the raceway itself.

You might just ask the electrical inspector how they feel about it.
 
Very funny - definitely don't want to offend offenders. :) Thanks for the input. Welding to wall but not to conduit. Got it.
 
I would use two hole straps! Weld both sides. Don't want the prisoners to rip the pipe out and hurt themselves :)

You may find in your specs that the state engineer is the inspector. I would check...
 
I would agree that welding the straps should be okay.. they require this so prisioners can not remove stuff for weapons right? do you have to weld the boxes to the walls as well? is removing the devices an issue in prison too? FYI I have never been in prison for any reason not even to visit..
 
tshea said:
I would use two hole straps! Weld both sides. Don't want the prisoners to rip the pipe out and hurt themselves :)

You may find in your specs that the state engineer is the inspector. I would check...
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Being in law enforcement as well as engineering, I second this suggestion. Anything to prevent them from making improvised weapons. They have lots of time on their hands and come up with all kind of tricks. I'm surprised the raceways aren't required to be in the walls and not exposed.

RC
 
rbalex said:
I was the author of 300.18 (B) and can assure you the limitation is on the raceway only.
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I was wondering Bob, what raceway is actually permitted to be welded? I would think that RMC could be welded in place if the conductors weren't installed yet.
 
Essentially the rule intends to prohibit any metal raceway (RMC, EMT, IMC, etc) from being welded to directly unless they are of a special design or the NEC specifically permits it. The basic substantiation was that direct welding damages both the external and internal finishes. While the external surfaces can reasonably be repaired, most internal surfaces can?t be.

I?ve seen RMC corrode ?from the inside ? out? over time in a few refineries I worked in. They were attempting to ?seal? long runs by welding the couplings. I?ve also seen a few runs of EMT tack welded for support. In the case RMC case it was particularly bad since the raceways were also used as the EGC.
 
The residents (inmates) have nothing to do other than try to tear things apart to make weapons. Given enough time, they will succeed no matter how you fasten it.
Don
 
The wall is metal? Is there concrete behind it? I think you'll have to get custom straps if you're going to weld them. I had a guy try to weld a cover to a box one time. Can't quite recall why. But he couldn't do it due to the metal composition. Perhaps a very skilled welder could make it happen. I suspect straps are not a very high quality metal that will lend itself to welding. Perhaps a screw type, can't recall the name, concrete anchor(if there is concrete behind the metal) then use something like red loctite on the anchor bolt. They make even better than red loctite I think for a pretty permanent bond.
 
prisoners have lots of spare time

prisoners have lots of spare time

Did a fire alarm in a city jail. We started with 1/2 grs, 2 hole straps and 5/16 tamper proof screws tapped into the steel cell walls. Felt pretty good that we got 150' installed the first day. Arrived the next morning to find all 150' of pipe ,straps and screws neatly stacked outside the dayroom holding a bunch of grinning prisoners. The head jailer (not the same one from the day before) chewed us out for leaving the material inside the lockup. After a few phone calls he was assured by the guy from the day before that no loose material was left behind. To this day I do not know how they did it. Needless to say we resorted to welding.
 
Ive welded boxes and straps to steel crane beams before, as well as to thick structural beams. Ive used a Mig welder and a DC arc welder with a 6013 rod for this purpose
 
I was an AA volunteer in 3 state prisons for a period of almost 6 years. The state has a strict non-smoking law. The "residents" that "dwell" there had a way of using tin foil in wall outlets to light their contraband smokes. Would the new 406.11 Tamper Resistant Receptacles in Dwelling Units apply to prisons?
 
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