|
Joined: Dec 2000
Posts: 4,294
Member
|
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.
|
|
|
|
Joined: Jan 2003
Posts: 4,391
Moderator
|
Runs should be parallel and perpendicular to the building. 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. if you were working in that ceiling, lost your balance, grabbed that run to balance yourself it would come down 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
Bob Badger Construction & Maintenance Electrician Massachusetts
|
|
|
|
Joined: Oct 2004
Posts: 265
Member
|
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.
|
|
|
|
Joined: Feb 2005
Posts: 219
Member
|
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
|
|
|
|
Joined: Jan 2003
Posts: 4,391
Moderator
|
Rob This type of support seems to be acceptable with most people here. I do not see that, what I see is that most of feel it is not an NEC violation. This is not a 3/4" run its a feeder with much more weight involved 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.
Bob Badger Construction & Maintenance Electrician Massachusetts
|
|
|
|
Joined: Feb 2005
Posts: 219
Member
|
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.
|
|
|
|
Joined: Dec 2000
Posts: 4,294
Member
|
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
|
|
|
|
Joined: Mar 2005
Posts: 1,803
Member
|
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).]
Wood work but can't!
|
|
|
|
Joined: Jan 2005
Posts: 5,445 Likes: 3
Cat Servant Member
|
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.
|
|
|
Posts: 44
Joined: August 2005
|
|
|
|