Exposed vertical risers with EMT

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VinceS

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Per 342.30(B)(3) IMC, and 343.30(B)(3) RMC, exposed vertical risers are permitted not exceeding 20 feet.

I have identified an installation which uses EMT with vertical risers. Section 358.30, (EMT securing and supporting), does not discuss vertical risers. The section 358, (in the 05, or 08 NEC), doesn't prohibit EMT vertical risers in writing, or permit vertical risers in writing.

Is there another section in the NEC which discusses vertical risers in EMT?

Is this a AHJ issue?

Is this permitted? (If so please provide a reference so I can understand more.)

I understood EMT vertical risers to be not permitted, but now I'm not sure.
 
Vertical risers of EMT are permitted as long as they are supported no more than every 10'.
IMC and RMC can be supported no more than 20' on a vertical riser as long as threaded couplings are used.
 
More information...

More information...

The vertical risers in question are of the type which drop from a horizontal run overhead then drop to a disconnect or panel. Its specifically this vertical drop which is in question.

ie... Imagine a EMT feed to a disconnect dropping 20' from a horizontal run overhead. Lets say for argument the drop is 20', and there is no supporting structure supporting the EMT during its run between the overhead and the disconnect.

A vertical drop down or up a supporting structure is not in question, as the 10' rule applies.
 
VinceS said:
A vertical drop down or up a supporting structure is not in question, as the 10' rule applies.
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Vince,

The 10' rule applies here as well, EMT must under all conditions be supported at least each 10' of run.

So if someone wants to drop down from a 20' ceiling to equipment in the middle of the room they will need to run some sort of rack down first and secure the EMT to that.

Or if it is more then 10' but less then 20' they could use RMC for that vertical section.
 
Thanks All...

Thanks All...

Thats what I thought, but when I went to quote chapter and verse I couldn't find the specific prohibition.
 
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