Emt support

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Location
US
In Commercial buildings in my area many AHJ'S require that everything I install above the suspended ceilings be supported by the top cord of the z purlins. All the existing work I see and the work we were doing just 5 year's ago could be supported with pencil rod from the bottom cord of the truss. Only heavy loads like trapeze, sprinkler pipe, plumbing pipe, and HVAC were required to be supported at the top cord. Most AHJ's still permit ceiling grid rods to be suspended from the bottom cord. Is this a new code? I have checked the NEC, the IBC and my light commercial construction standards and practices manual and can find no specific code referencing this issue.
My interest is in having a specific source I can cite for clients. When I inform them that the cost of their build out is higher because we must re hang all of the existing emt and junction boxes I would like to have a specific code requirement I can cite.



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qcroanoke

Sometimes I don't know if I'm the boxer or the bag
Location
Roanoke, VA.
Occupation
Sorta retired........
In Commercial buildings in my area many AHJ'S require that everything I install above the suspended ceilings be supported by the top cord of the z purlins. All the existing work I see and the work we were doing just 5 year's ago could be supported with pencil rod from the bottom cord of the truss. Only heavy loads like trapeze, sprinkler pipe, plumbing pipe, and HVAC were required to be supported at the top cord. Most AHJ's still permit ceiling grid rods to be suspended from the bottom cord. Is this a new code? I have checked the NEC, the IBC and my light commercial construction standards and practices manual and can find no specific code referencing this issue.
My interest is in having a specific source I can cite for clients. When I inform them that the cost of their build out is higher because we must re hang all of the existing emt and junction boxes I would like to have a specific code requirement I can cite.



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I believe I'd ask the inspector for the code reference.
If he requires it he must provide the chapter and verse.
 

don_resqcapt19

Moderator
Staff member
Location
Illinois
Occupation
retired electrician
You have to check the structural codes for that one...as I recall there was a permission to use the bottom chord for light loads, but I don't remember the weigh limit.
 
Location
US
Each spring when the local inspectors come back from their paid vacations/seminars they have a new interpretation of an existing code. In one case the tenant hired a structural engineer who evaluated the trusses and wrote a document to be added to the submitted prints attesting to the trusses structural soundness to support 1/2" emt and 1900 boxes.

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mwm1752

Senior Member
Location
Aspen, Colo
Unfortunately, learning new concepts and adjusting enforcements is the nature of the beast -- Take into consideration that know one knows it all -- If they say they do then there is your sign -- I attend training sessions quite often & let me tell you I do not consider them a paid vacation( a vacation has me with a cold beverage & sitting on a boat) -- The entity I work for promotes advance learning in order be better in the field & for the contractor base -- We may not get it right all of the time but neither do contractors but at least some are out there training to get it right -- I find it encouraging when a contractor researches a possible issue in order to be prepared when confronted in the field (not many do) so I would think a contractor would appreciate inspectors obtaining training to better assist them. Not quite sure what code you inspector is enforcing but you do have the right to ask -- NEC 300.11 is my quick answer
 

cowboyjwc

Moderator
Staff member
Location
Simi Valley, CA
Probably comes from the truss manufacturer and it's not a code requirement.

There are many standards that inspectors are forced to use and there is no code section other than one that refers you to the standards. Oh and standards are very expensive so most jurisdictions do not buy them.

If you think the inspector is wrong, then you could always prove it too. It's not always up to the inspector to show you he's right.
 
Location
US
Your are correct, evolving standards and practices are how our industry grows I just find the lack of consistency disturbing. I am too German I guess.
On an unrelated topic in some towns the local AHJ'S require the emergency lighting to be on its own separate circuit, while in others the AHJ'S want each emergency light fixture to be on the local lighting circuit. The latter makes some sense to me, but is there a specific code that addresses EM lighting circuits.

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don_resqcapt19

Moderator
Staff member
Location
Illinois
Occupation
retired electrician
Your are correct, evolving standards and practices are how our industry grows I just find the lack of consistency disturbing. I am too German I guess.
On an unrelated topic in some towns the local AHJ'S require the emergency lighting to be on its own separate circuit, while in others the AHJ'S want each emergency light fixture to be on the local lighting circuit. The latter makes some sense to me, but is there a specific code that addresses EM lighting circuits.

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Take a look at 700.12(F)....in general emergency lighting that has batteries(unit equipment) must be fed from the circuit that supplies power to the lighting in the area where the EM light is installed.
 

Carultch

Senior Member
Location
Massachusetts
In Commercial buildings in my area many AHJ'S require that everything I install above the suspended ceilings be supported by the top cord of the z purlins. All the existing work I see and the work we were doing just 5 year's ago could be supported with pencil rod from the bottom cord of the truss. Only heavy loads like trapeze, sprinkler pipe, plumbing pipe, and HVAC were required to be supported at the top cord. Most AHJ's still permit ceiling grid rods to be suspended from the bottom cord. Is this a new code? I have checked the NEC, the IBC and my light commercial construction standards and practices manual and can find no specific code referencing this issue.
My interest is in having a specific source I can cite for clients. When I inform them that the cost of their build out is higher because we must re hang all of the existing emt and junction boxes I would like to have a specific code requirement I can cite.



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As I understand it, the NEC doesn't govern how a structural conduit support is built. You are required to support conduit at the intervals specified, and in a manner that is strong enough to support the load of the conduit, per all applicable structural codes, and you can't use a raceway as a mount if it is already serving a purpose as a raceway, but that is about it.
 

cowboyjwc

Moderator
Staff member
Location
Simi Valley, CA
Your are correct, evolving standards and practices are how our industry grows I just find the lack of consistency disturbing. I am too German I guess.
On an unrelated topic in some towns the local AHJ'S require the emergency lighting to be on its own separate circuit, while in others the AHJ'S want each emergency light fixture to be on the local lighting circuit. The latter makes some sense to me, but is there a specific code that addresses EM lighting circuits.

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I won't argue with that, I would bet as a rule that calls don't change just from jurisdiction to jurisdiction, but from desk to desk.
 
Location
US
With regard to the EM lighting I was aware of the code, keep it on the local lighting circuit. However in a recent commercial build out we were required to rewire all on a single circuit. I will mention that in many cases the AHJ performing the electrical inspection was not himself an electrician. In many of the communities I do work in they are the structural inspectors doing double duty.

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cowboyjwc

Moderator
Staff member
Location
Simi Valley, CA
Where are these communites? Are the inspectors required to have any electrical qualifications?
He's a combination inspector and many city's are going to that. They think they get more bang for their buck, than having two or three guys that only do electrical, plumbing and/or mechanical, just have one guy do it all. If that's what you have, as a group you should go to the local building official and see what can be done. Used to hate when an ex plumber would tell me what I did wrong, especially when he was wrong.
 

cowboyjwc

Moderator
Staff member
Location
Simi Valley, CA
I am also a combination inspector but the state regs require the electrical inspections be done by a licensed electrician.
Here not so much and I didn't mean to sound like I was putting anyone down, but there is no way that you can know everything that you need to know about every trade. I wouldn't want to be a combination inspector.
 
Location
US
DuPage county inspector is a former wood butcher, he did my electrical rough inspection a month ago, the plumbing contractor got a plumber. Winfield, Wheaton, Downers Grove have always required me to coordinate my electrical rough inspection with the framers inspection because it's the same inspector.

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mwm1752

Senior Member
Location
Aspen, Colo
Here not so much and I didn't mean to sound like I was putting anyone down, but there is no way that you can know everything that you need to know about every trade. I wouldn't want to be a combination inspector.

I didn't take it as a put down, & know one can know everything even if it was a single trade IMO. There is alot to consider being a Combination inspector been doing it now for 9 years -- I would say the electrical trade has the biggest book & creative codes -- Certainly has help that I've been in the trade 30 years prior to testing out for plumbing. mechanical & building -- Working with tradesmen, plan examiners & code change hearings is a must for continual learning, now I would not want to be anything but a comination inspector. very interesting -- I enjoy the learning & challenges so my next endevor is a CBO certification.
 

cowboyjwc

Moderator
Staff member
Location
Simi Valley, CA
I didn't take it as a put down, & know one can know everything even if it was a single trade IMO. There is alot to consider being a Combination inspector been doing it now for 9 years -- I would say the electrical trade has the biggest book & creative codes -- Certainly has help that I've been in the trade 30 years prior to testing out for plumbing. mechanical & building -- Working with tradesmen, plan examiners & code change hearings is a must for continual learning, now I would not want to be anything but a comination inspector. very interesting -- I enjoy the learning & challenges so my next endevor is a CBO certification.
:thumbsup:
 

Fulthrotl

~Autocorrect is My Worst Enema.~
In Commercial buildings in my area many AHJ'S require that everything I install above the suspended ceilings be supported by the top cord of the z purlins. All the existing work I see and the work we were doing just 5 year's ago could be supported with pencil rod from the bottom cord of the truss. Only heavy loads like trapeze, sprinkler pipe, plumbing pipe, and HVAC were required to be supported at the top cord.

i'm feeling stupid at the moment, but i'm assuming you are talking about combo truss with wood stringers
and thinwall tubing for the lattice.....:dunce:

i live in earthquake land, and pretty much everything here gets hung from the bottom stringer.
where you have an all steel truss, made of back to back angle iron for the stringers, with angle
iron at a 45 degree angle for the segments, dropping running thread from the lower one is the
norm.... and not trivial loads, either. half inch rod, and racks of 4" EMT, and a beam clamp is
what is used around here. the only time i've used the top, is if i throw a piece of unistrut across
the top of the truss, in the cavities of the robertson decking, to drop a rod in a specific place.
and i'll seldom use a beam clamp, just use square strut washers between the angles of the bottom
stringer, and put the rod in between them.

i've never had a do over in 40 years of this... :huh:
 
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