ECN Electrical Forum
Discussion Forums for Electricians, Inspectors and Related Professionals

OK, "perforated strapping tape", as it is called around here could be cited as not being listed/labeled for use in supporting electrical raceways. Now, that is stretching a bit, but a few AHJ's have written 'reds' for using it.

I, as a contractor would not allow this item. I as an AHJ, have not seen anyone use it. Would I write a 'red'; based on the above, yes. It may be "Plumbers xxx", that is NOT "Electrical xxx".

John

John,

That presents a problem. Many of the commonly used conduit supports, such as strut straps, are not listed products.
Don

Don:
Sorry for the lag, hectic week.

OK, I am not aware of what you said....you are refering to unistrut 2 piece straps, and the Caddy items??

I'm under the impression that Caddy items are approved for support/etc of electrical items. Am I incorrect?

John

Hot Line, you've hit on the point of this thread..the NEC simply say to support the pipe; it does not specify how.

Now, many would say that the code needs to be more specific, that listing bodies need a wider fief; I disagree.

An AHJ, using the NECA workmansip standard as a guide, would not allow this strapping.

"Electric Work" is not just a job...it's both a SKILLED trade, and a professional. A journeyman is hired for his knowledge, experience, and judgement. You just can't get around having to make many, many judgement calls every day.

John I have never seen a UL listed strut clip.

There are some UL listed strut products but they have to do with using strut as a raceway.

Reno, IMO you can not enforce workmanship, that is like enforcing good taste.

It is far to subjective of a subject.

Yes I see that strap in the photo of a poor workmanship. But I can not say it is any less safe then a mini supported by a rod.

Bob

Ok, I took a short piece of 1-1/2" EMT, supported it with a piece of this stuff, and hung from it (200#) No problem. Used 1/4X2-1/2" lag screw at top, with washer, and 1/4-20 Stove Bolt, with washers each side, at the bottom.
For some weights of EMT & Conductors

The Powerstrut Catalog has some good application data

>>But I can not say it is any less safe then a mini supported by a rod.<<

OK I'll say it, it is less safe!

The original question was never about what is Code or is this a Listed product. Put that run in a hardy quake zone... give it good 6.0 or better and it will remove the T-Bar and lights below it. Seeing how it was submitted by Reno, he lives in "Quake Country" which receives quakes all the time and is a candidate for a strong one.

Rob

You can say it, but you can not prove it in the least.

Have you any experience supporting EMT with this perf strap?

I think an AHJ could cite 300.11(A), stating that the raceway isn't "fastened in place", although I don't think I would get too excited about it.

Also, I think an AHJ could make a stretch and establish his definition of "fastened in place" as meaning secured at both ends, such as is the requirement for suspended cieling when using support wires.

Electure;
I wondered how you were going to test the stuff - never thought you'd suspend yourself on it!!!
FYI a 1/4" bolt in single shear should safely take around 600lbf, so it's failure load is around the same magnitude as the strap. Be careful when assessing breaking loads on components like this; shock loadings, (like a falling object, or a seismic event or putting your weight on the EMT too hastily!), can generate stresses many times the apparent static stress. For instance a weight suspended a hairs breadth from a surface and allowed to drop by gravity doubles the stress momentarily, and it gets worse as the distance fallen increases.
YOU CAME CLOSE!

Sorry, stress my pet subject!
Alan