Article 358.30

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jerm

jerm

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Location
Tulsa, Ok
Anyone ever invoked 358.30 (B) ['05]?

The NEC said:
358.30 Securing and Supporting. EMT Shall be installed as a complete system in accordance with 300.18 and shall be securely fastened in place and supported in accordance with 358.30 (A) and (B).

...

(B) Supports. Horizontal runs of EMT supported by openings through framing members at intervals not greater than 3 m (10 ft) and securely fastened within 900 mm (3 ft) of termination points shall be permitted.
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I have an application where strapping isn't possible... I'll post pics if you don't believe me! (It's fished between the roof and the truss, with truss on 6' centers, so the "framing members" are closer than the 3 m [10'] minimum.)

Don't know if inspector will let me by with this rule.

Any experience with this type of install, anyone at all?
 
How could he not accept it? It is right there in the NEC and to the point at that. IMSO, this rule also applies to bar joists. Now, with no strapping, I suppose someone might bring up that there should be a redundant equipment ground wire pulled in the tubing.
 
You slid the EMT between the corrugations of the tin, on top of the bar joists? Pretty typical install. Gotta beware of those long screws the roofers use to attach their foam down. That'll get you every time. Trusses are framing members, absolutely. You're good to do with that code section, in my opinion.
 
A couple years ago we ran conduit this way inside steel trusses that where 6' on center and fastened it only at the ends. It was several long parrellel runs, that we kept separated with uni-struts & straps but the struts did not mount to anything else. The inspector was fine with it.

Ironically, we got questioned about section 300.11 as they dropped wires from the trusses in one section to make a suspended ceiling for a partitioned office area. You may want to look at 300.11 in case it applies to you.

I'm not sure this helps as I think it is like rolling dice when it comes to inspectors but I do believe our install was safe.
 
I'd run it and if it doesn't pass for some reason and you don't want to fight it break out the caddy catalog. I bet something in there would work.
 
mdshunk said:
You slid the EMT between the corrugations of the tin, on top of the bar joists? Pretty typical install.
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The 2008 NEC now prohibits doing that, a major change in my installations.
 
iwire said:
The 2008 NEC now prohibits doing that, a major change in my installations.
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we were required to run conduit in some box stores in this fashion. I think it is idiotic - when the roof gets reroofed someone is in for the shock of their life (if they live). the reason they wanted the pipe up there ? "we like the way it looks".

I'm glad this is now against code (if that's really the case)
 
300.4(E) Cables and Raceways Installed Under Roof Decking. A cable or raceway type wring method, installed in exposed or concealed locations under metal-corrugated sheet roof decking, shall be installed and supported so the nearest outside surface of the cable or raceway is not less than 1 ? in. from the nearest surface of the roof decking.
FPN: Roof decking material is often repaired or replaced after the initial raceway or cabling and roofing installion may be penetrated by the screws or other mechanical devices designed to provide ?hold down? strength of the water-proof membrane or roof insulating material.
​
Exception: Rigid metal conduit and intermediate metal conduit shall not be required to comply with 300.4(E).
 
don_resqcapt19 said:
[/INDENT]Exception: Rigid metal conduit and intermediate metal conduit shall not be required to comply with 300.4(E).
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That's an interesting exception that might disappear too someday. I see those insulation screws (self drilling) drilled right through the top chord of the bar joist pretty regularly. If it can get through that, it'll get through RMC and IMC.
 
nakulak said:
when the roof gets reroofed someone is in for the shock of their life (if they live). the reason they wanted the pipe up there ? "we like the way it looks".
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Sure would like to know how they would get a shock after the screw runs through the grounded decking and grounded raceway before hitting any live conductor.

Not to mention the tool doing the driving will either be insulated or grounded.
 
So, this is only for the 'roof ' of a building ? The same stuff is used on a

second floor that will get concrete poured on top, in that case can you run

in the space above the Z-bar ?
 
benaround said:
So, this is only for the

'roof ' of a building ? The same stuff is

used on a second floor that

will get concrete poured on

top, in that case can you run

in the space above the Z-bar ?
Click to expand...

Apparently you can. Why you press enter so much? Is your wordwrap broken? :cool:
 
The rule only applies to the roof because of the long screws that are used when the roof insulation is installed and when the deck is re-roofed in the future. We don't have the same type of issues with an interior concrete on metal deck system. In this it would be rare for additional screws to be installed after the original installation.
Don
 
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