Independently supported

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Djelite

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Electrician
Every installatin has to be independently supported. Does that mean you cant support conduit etc from an already independently supported installation? For example extending rack of conduit from an already independently supported rack if you connect to the kindorff and not the threaded rod
 
Where does it say that everything has to be independently supported and independent of what is the question. If you have an exisiting rack you can certainly extend it and hang off of it.
 
Extending it is not the question, the question is can you extend it from the kindoff (to make a smaller rack) and not the threaded rod
 
I've been called on this "independent support" nonsense before. I think where they are getting it is from the part about ceiling grid wires where if you use wires they have to be independent of the ceiling grid support wires. There is no general requirement for independent support of electrical stuff.
 
Djelite said:
Extending it is not the question, the question is can you extend it from the kindoff (to make a smaller rack) and not the threaded rod
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Not an issue. Regardless of what you do it has to be adequate to support whatever it is you're supporting.
 
Well you cant support a conduit with another conduit . You cant support cables with conduits or support a box with another box. Why can you support a rack of conduit from a kindoff a saddle washer and nut which where never tested for this application
 
Djelite said:
Why can you support a rack of conduit from a kindoff a saddle washer and nut which where never tested for this application
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When are racks tested for a specific application? It's up to the inspector to decide what is adequate support. There are industry standards that are followed like what size rod to use also strut manufacturers have catalog information regarding what their products can support.
 
They are designed to carry a specific load. This is my argument. We were running 4 inch pvc coded galvanized conduit. Each anchor , each threaded rod is tested to carry a specific load. Each rack had around 6 conduits. Then someone came and instead of using the threaded rod and extending the load as designed. They placed 2 threaded rods thru the kindoff to make their rack. I dont think washers and nuts are design to carry a load like this neither is the kindorff there by making it no independently supported
 
infinity said:
When are racks tested for a specific application? It's up to the inspector to decide what is adequate support. There are industry standards that are followed like what size rod to use also strut manufacturers have catalog information regarding what their products can support.
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Not a specific application. Im talking about a specific load
 
Djelite said:
Then someone came and instead of using the threaded rod and extending the load as designed. They placed 2 threaded rods thru the kindoff to make their rack. I dont think washers and nuts are design to carry a load like this neither is the kindorff there by making it no independently supported
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Kindorf racks are built with nuts and washers why would adding nuts and washers and new rack not be strong enough to support the load? If you're saying that the original rack design was only strong enough to support the existing 6 conduits then you might have a legitimate argument about adding to it.
 
Racks are built with nuts and washers to secure and fasten the rack in place not carry the load of a number of conduits. Imo thats like saying you can use any size kindoff or any size anchor to support any size equipment or conduit
 
Djelite said:
Racks are built with nuts and washers to secure and fasten the rack in place not carry the load of a number of conduits. Imo thats like saying you can use any size kindoff or any size anchor to support any size equipment or conduit
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There are no requirements in the NEC that this stuff be designed or analyzed by a structural engineer. I think we have to just trust the electricians in the field and let them do their job.

If you want to run some numbers, Google "bolt tensile stress area" to find the cross sectional area of the threaded rod. Generally threaded rod is a low-grade steel probably 60,000 PSI tensile strength, but You'll probably find it's plenty strong enough.
 
Djelite said:
Racks are built with nuts and washers to secure and fasten the rack in place not carry the load of a number of conduits. Imo thats like saying you can use any size kindoff or any size anchor to support any size equipment or conduit
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Every trapeze rack I have ever installed had the total weight of the rack and the conduits supported by the anchor, threaded rod, and washers.

The only question is if the original rack design can support the additional weight of hanging another rack from the first one.
 
I have been on a project where we were adding to an existing trappeze and had to have a siesmic engineer give a blessing on it. We had to give him the weight of the conduit and wire and in the end we had to add some down rods at intervals along the path.
 
don_resqcapt19 said:
Every trapeze rack I have ever installed had the total weight of the rack and the conduits supported by the anchor, threaded rod, and washers.

The only question is if the original rack design can support the additional weight of hanging another rack from the first one.
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If you add another and extend the original threaded rods but support from the actual kindoff itself you are now depending on nuts and washers to carry the load
 
Djelite said:
If you add another and extend the original threaded rods but support from the actual kindoff itself you are now depending on nuts and washers to carry the load
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I'm not understanding why you keep asking about nuts and washers, that's what connects the racks to the rods and other strut
components.
 
"support from the actual kindoff itself"
What is a kindoff ?
Slang for something or miss spelling.
Thank you
Question, are you discussion using a coupling nut and adding rod for additional rack.
 
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