Supporting EMT to a metal shed and roof

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Jpflex

Jpflex

Electrician big leagues
Location
Victorville
Occupation
Electrician commercial and residential
Today my boss tripped out today not because the transformer, breaker panels, heat lamp and GFCI breaker wasn’t working (which they were) but because the EMT and round box for the heat lamp was supported to the metal shed roof.

Without checking the book I believe the NEC code requires EMT to be supported and secured within every 10 feet and every 3 feet of termination such as to the round box to the heat lamp as pictured

My boss said the holes in the roof would allow water to enter the shed although the self tappers I used had rubber seals and were listed as water tight

He made me disconnect the EMT run and caulk the holes

Do you think my approach was ok?
 

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Those screws are designed to be installed through the outside of the metal roof. They can be used to screw into wood on the inside that can be used to support the box and raceway.
 
infinity said:
Those screws are designed to be installed through the outside of the metal roof. They can be used to screw into wood on the inside that can be used to support the box and raceway.
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I see but it would be real hard to line up box from on top of roof if drilling from top of roof and it wouldn’t hold the box in this orientation
 
Your approach was not ok, and your boss is 100% correct. It would never be acceptable to me, to attach using screws though a roof like that.
 
augie47 said:
Bob: Would 300.4 (E) apply here ??
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While I don't believe that the intent would be that 300.4(E) would apply, I think the wording says that it does.
The intent of that section is for installations where the actual roofing material is screwed to the metal decking. This seems to be an installation where the metal deck is the actual waterproofing material.
 
don_resqcapt19 said:
Your approach was not ok, and your boss is 100% correct. It would never be acceptable to me, to attach using screws though a roof like that.
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Ok then what would be a proper method to support EMT and a lamp under the metal corrugated roof?

Code specifically requires EMT to be secured and supported within so many feet. Something would have to be drilled to hold rquipmrnt? And the self tappers were listed as rain tight
 
Possibly follow Post #2, Screw wood blocks to the ceiling using your roofing screws and support your EMT & Fixture box to the blocks.
 
Jpflex said:
I see but it would be real hard to line up box from on top of roof if drilling from top of roof and it wouldn’t hold the box in this orientation
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You could glue a wood block in with construction adhesive. When it's all hardened you could add a screw through the metal if desired.
 
I kinda get it but wasn’t the wood’s purpose to avoid holes in the roof? If I were to glue a board to the ceiling and then drill holes through both the wood and metal roof doesn’t this defeat the purpose?

Or if holes only on the wood, would the woods glue hold for the weight over time or be safe?
 
Jpflex said:
I kinda get it but wasn’t the wood’s purpose to avoid holes in the roof? If I were to glue a board to the ceiling and then drill holes through both the wood and metal roof doesn’t this defeat the purpose?

Or if holes only on the wood, would the woods glue hold for the weight over time or be safe?
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Jpflex said:
Ok then what would be a proper method to support EMT and a lamp under the metal corrugated roof?

Code specifically requires EMT to be secured and supported within so many feet. Something would have to be drilled to hold rquipmrnt? And the self tappers were listed as rain tight
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I am 100% sure that the self tappers you used are not listed as raintight when you installed them from the inside.
 
Those sheets don't hang out there with nothing above them. Those are interior sheeting. They have some purlins above them. Stretch strut between two and hang your box there. Or get directly to the purlin. That would have required a reminder of some sort about what the heck are you doing.

eta: If that is the roof sheeting the discussion would have been more to the point. Butt chewing justly deserved.
 
Jpflex said:
I kinda get it but wasn’t the wood’s purpose to avoid holes in the roof? If I were to glue a board to the ceiling and then drill holes through both the wood and metal roof doesn’t this defeat the purpose?

Or if holes only on the wood, would the woods glue hold for the weight over time or be safe?
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Those screws are designed to be installed externally through a metal roof. The screw would hold the wood in from the outside not the inside.
 
What is the roof secured to? Wood members? Metal framing? Could your box or conduits be supported by those? If not, could you run of piece of 7/8" strut between them to secure your boxes and conduit? I agree that the screws are listed to be installed from the exterior of the roofing.
 
ptonsparky said:
Those sheets don't hang out there with nothing above them. Those are interior sheeting. They have some purlins above them. Stretch strut between two and hang your box there. Or get directly to the purlin. That would have required a reminder of some sort about what the heck are you doing.

eta: If that is the roof sheeting the discussion would have been more to the point. Butt chewing justly deserved.
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No instructions/ specifications were given just told to put in a heat lamp. I focused more on the best scheme to convert the 240 volt feeder to usable 120 from a transformer + wire and OCPD etc. I do not work on containers/ sheds typically as most electrical work is on standard drywall, but at least I’ll seek another approach next time. Thanks
 
Rick 0920 said:
What is the roof secured to? Wood members? Metal framing? Could your box or conduits be supported by those? If not, could you run of piece of 7/8" strut between them to secure your boxes and conduit? I agree that the screws are listed to be installed from the exterior of the roofing.
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Roof is just corrugated sheet metal and nothing more
 
The boss a
Jpflex said:
Roof is just corrugated sheet metal and nothing more
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Apparently the boss was expecting me to just dangle the heat lamp from an unsupported/ non secured EMT

I did what I did to supported the EMT according to the 10’ and 3’ foot rule according to NEC
 
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