Industrial location? Probably strong enough in direct tension, (apart from the dubious fix with a couple of clout nails), but there's no lateral restraint. Is this strap galvanised steel or plastic?
The floor joists look on the thin side too. They look like floorboarding laid on edge! The risk here is joists 'rolling'. No herring-bone struts visible to counter this.

Alan

spelling

[This message has been edited by Alan Belson (edited 11-22-2005).]

Honestly I have never done that.

That aside I think we would be hard pressed to cite a legitimate violation here.

We might say that...


...requires the use of listed hangers but that means unistrut clips will be a violation as well.

Bob

Alan- The location was a government office. Everything you see was concealed above a suspended ceiling.
The wood joists are actually 2x12's (actual measure more like 1 1/2 x 10 1/2 inches) used as rafters to support the roof.
To the right, you can just make out the solid wood blocking, used as lateral bracing between the rafters.
It's not obvious in the pic, but there is a significant slope to these rafters. Let's just say that this "flat" roof has enough slope you don't need to worry about water forming puddles!

The "plumbers' tape" is galvanised steel, of a gauge just a little too heavy to be easily cut by your diagonal cutters, but easilt cut with aviation snips. (Maybe 18 gauge?)

Rono;
My apologies! My dopey old brain read that as one pic showing 2 floors at a landing! Duh! Lumber of those dimensions is not readily obtainable off the shelf at a builders' merchants in thr UK or Fr., I thought they were about 1x8

Alan

I really don't see that installation as any different from the use of 1/4" threaded rod and a mini.
Don

Its "hack electrical work"!

Runs should be parallel and purpendicular to the building. The strapping is not legal in my area due to the quake zone I live in, but what moron would use that material to support any conduit run anyway.
A good quake would take it out. Or, if you were working in that cieling, lost your balance, grabbed that run to balance yourself it would come down.

adequate? probably.

workmanlike? no way.

>>Or, if you were working in that cieling, lost your balance, grabbed that run to balance yourself it would come down.<<

I have seen 3/4 emt "batwinged" to ceiling wires before and thought that same thing...

True enough.

There are lots of other things that would come down if you grabbed them while falling.
A ceiling grid cross tee for instance. How about a piece of aluminum flex?

I don't use this stuff for supporting conduit, but it looks, like trollog says, stronger than a Caddy clip.
And like iwire brought up Unistrut, metal framing, or a wood 2X4 doesn't carry a UL listing, although all are acceptable supports.

Why?

Thinking of it from only an electrical stand point you are only adding length to the circuit.

Thinking of it from the customers side you are only adding costs to the job.

99% of the time I do run parallel and perpendicular to the building most time that is the easy way to go.

That aside to make a blanket statement that all runs should be parallel and perpendicular to the building IMO is wrong.

IMO all code compliant options should be presented to the person footing the bill.


First I doubt that would come down, unless you are extraordinarily heavy.

Second the ability of any electrical equipment to support a falling person is hardly the measure used to install electrical equipment.

Use the right ladder and don't fall.

Bob

Look at Caddy companies "PCS2" & "K8" through "K16" supports. http://www.erico.com/products/CADDYcfcCableConduit.asp http://www.erico.com/products/CADDYcfcConduitHangers.asp

I doubt that they would support someone who is falling, but they are designed to support conduits.




[This message has been edited by Redsy (edited 11-24-2005).]

Most of our plans the EE call for runs to be parallel iwire, but its not a code issue.

Sierra electrician, you are requiring that all pipe runs support a falling man? I doubt very many suspended 1/2 EMT runs would support a falling man.

dmattox
I think my issue is more with the strapping than a falling man. This type of support seems to be acceptable with most people here. This is not a 3/4" run its a feeder with much more weight involved. To me this means substandard practice and materials are ok with them. The falling man was a bad example, sorry.
The runs being purpendicular and parallel... are just quality workmanship. Iv'e never lost a job because I bid this way. Much of the work I bid requires that all runs be installed this way. Its a practice I have put into every job I do.

JMHO
Rob

Rob


I do not see that, what I see is that most of feel it is not an NEC violation.


No matter what that 2" is filled with that plumbers tape will hold it.

Perhaps you are not familiar with it's strength.

Plumbers have used that for years supporting cast iron waste pipes.

Keep in mind that the code is just a minimum, if you feel that needs 3/4" rod you are more than free to do so.

Take notice of the plumbing pipe to the right, along the CMU wall. That is "Proper Strapping". Plumbers tape which I am quite familiar with is not strong enough to support this weight properly.

Yes, I live in earthquake country too, and this type of tape is used for a number of applications, like Securing Water Heaters .
I've actually got some, I'll see if I can find it and do a strength test

1" x 1/32" steel strap, with 5/32" central holes can be taken to at least 700lbf with a safety margin. I reckon it would start to 'yield' at about 1200lbf and snap around the same load, with a % extension dependant on the temper and work hardening produced in manufacture. End fixings will be the weak point.

A 2x4 softwood scantling could be (theoretically) loaded in tension to around 6000lbf, depending on grade, seasoning and species, but the fixings [ie nails or screws ], again, would probably fail first.

Timber has the advantage of rigidity; in that it can be loaded in tension, compression and bending.

Alan

ps. Steel is about 10 times heavier than average softwoods, and around 10 times stiffer. All the loadbearing materials we use have this rough correlation of weight to stiffness, except, strangely, for carbon-fiber and other exotic matrix materials.


[This message has been edited by Alan Belson (edited 11-25-2005).]

I remember, when I was learning the trade, I'd proudly show the boss my work, only to hear "We don't do that!"

This pic is a good example; I can't think of any sparky who would hang pipe with plumbers' tape- but I also think it is not a code violation.

Fire sprinklers are required to be mounted in a manner that will support the pipe, water, and 300 pounds of load. Sprinkler guys are only allowed to use specifically listed hangers. We are not under those restrictions.

If I recall correctly, this was a 1 1/2 pipe, containing three 2/0 wires, feeding a 150 amp panel.

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

Ryan,
So that AHJ would not accept threaded rod and a mini?
Don

John,
I don't use much Caddy stuff as it is not suitable for industrial work, but I think that you will find that it is listed for "positioning" and not for support. Very few of the conduit supports used in industrial work have any listing.
Don

Hi Don. Once again, I don't agree with what I wrote, but I could easily see an inspector making this stretch. With that in mind, I could see a person turning down an all-thread and mineralac installation as well.

Ryan,
Just to push a bit...what about the common trapeze hanger?...threaded rod and strut.
Don

You're killin' me Don!

I think someone might be more inclined to buy a trapeze, because with two threaded rods and strut straps the conduits are "fastened in place" more than they are with a single rod and a mini.

Seems to me like alot of inspectors will pass anything that has a "caddy" type clip or hanger, but will find all sorts of problems with anything not out of a package or box. Tie wire for conduit securing in metal stud horizontal runs comes to mind. If I put a "caddy" securing clip on -no problems. If I tie wire the thing to the stud - problem. The plumber's tape shown in the picture is crummy, but it is just as good or better than the accepted practice of using an "identified" grid ceiling wire as a hanger with a k-16 clip on it. Since we have a wood ceiling in this picture what about if the installer had of secured a verticle 2" x 6" down from the joist, drilled a hole in it, and ran his pipe through it. Would this have caused a problem for anyone?.

Slightly off-topic, but still closely related:
I don't see much difference between this and the widely accepted and time honored practice of suspending fluorescent fixtures from jack chain, in continuous rows or otherwise.(except this stuff is stronger)
Have you ever heard of a job being turned down for using (non listed) jack chain?

[This message has been edited by electure (edited 12-01-2005).]

I have seen it done, but never to that degree (length), and also at least two screws into the wood for support.

As far as the parallel or perpendicular argument? Many towns around here have such rules written into their local Codes... the "whenever practicable" part is AHJ's discretion.

Don:
As always, your input is appreciated & enlightning.

IMHO, hanging pipe on rod & strut is my 'choice', and the choice of most around here. Occasionally, I 'see' a single rod, with a cowboy hanger.

THe plumbers perforated strap, as I said is not in the sparky's trucks here....maybe a 'DIY', or a gypsy. It's a Jersey thing I guess; not to use it.

BTW, "Workmanship" is not enforcable in NJ.

John