Conduit installation between buildings

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electro7

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Northern CA, US
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Hi,

Is it okay to span two different structures overhead with EMT conduit?

I have an application where we are installing solar panels on two separate structures that are 4ft apart. I was wondering if I could connect the strings overhead via EMT conduit from roof to roof? Obviously it would be supported on both structures. One structure is a house the other is a shed/garage of some sort (non-dwelling). Whats the code section?

Thanks
 
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jeremy.zinkofsky

Senior Member
Location
nj
electro7 said:
Hi,

Is it okay to span two different structures overhead with EMT conduit?

I have an application where we are installing solar panels on two separate structures that are 4ft apart. I was wondering if I could connect the strings overhead via EMT conduit from roof to roof? Obviously it would be supported on both structures. One structure is a house the other is a shed/garage of some sort (non-dwelling). Whats the code section?

Thanks
Click to expand...

225.10 allows for this application and you can run it across two structures supported as stated in 358.30. However, you should make sure that you look over 358.10 & 358.12 if you are going to use EMT.
 
charlie b

charlie b

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I would have some concern over differential movement between the two structures. If the wind causes one to move even a fraction of an inch, and if that one blocks the wind from striking the other, then you will be calling upon the EMT to serve as a structural member. It is not designed to handle that job. Is there some type of flexible connector or other means that would allow for some motion?
 
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GoldDigger

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electro7 said:
AHJ is not allowing because he does not see how it is protected from physical damage.
Click to expand...

Would he allow RGS instead?
It is the wires or cables that need to be protected from damage according to the NEC, not the raceway.
If the conduit is OK on the roof of the building, it should be OK on the span too as long as it is high enough that it won't be run into by a person or a forklift or be used as a chin-up bar.
 
Fulthrotl

Fulthrotl

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electro7 said:
AHJ is not allowing because he does not see how it is protected from physical damage.
Click to expand...

2" GRC won't flex much. even if you don't need 2" trade
size, i'd use 2" minimum. EMT's a bit cheesy for something like this.

put two pieces of 1 5/8" strut 1' long on each roof, 1' apart.

strap one side with two strut straps, so it won't wiggle.
get a 18" piece of 2 1/2" grc and strap it to the other
struts on the other roof, sleeving the 2" thru it.
put a condulet on each end.

now, it's solid, and won't thrash around, but can wiggle
when and if the buildings move.

they make a sort of U joint for conduits to swivel and
telescope somewhat. i've used them in 6" size. don't
know if they come in smaller sizes. it was 20+ years
ago, so i don't remember if it was C-H or appelton,
but i'm pretty sure it was one or the other.

they were breathtakingly expensive back then.
i'd see if you can get away with the thing i mentioned.
 
infinity

infinity

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New Jersey
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electro7 said:
AHJ is not allowing because he does not see how it is protected from physical damage.
Click to expand...

What code section did he cite? EMT is suspended on conduit racks all of the time and would need to be subject to severe physical damage to be prohibited. This is really no different.
 
Ponchik

Ponchik

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Location
CA
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Electronologist
Why not use two pieces of EMT from the structures and couple them midair using LTFMC.
 
Ponchik

Ponchik

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CA
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infinity said:
What code section did he cite? EMT is suspended on conduit racks all of the time and would need to be subject to severe physical damage to be prohibited. This is really no different.
Click to expand...

I believe AHJ's concern is the movement of the structures that will decouple the EMT.
 
ADub

ADub

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Midwest
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Estimator/Project Manager
Conduit installation between buildings

Carultch said:
Which part is the yuck part? The EMT or the LFMC?
Click to expand...

The lfmc. I know it's functional but I can just picture it in my mind and it's disturbing. I'd probably use grc over emt as well with no flex. The buildings aren't going anywhere and if they move enough to stress the pipe there's bigger issues


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