Bonding framing members

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It's there somewhere. Someone will post it. Don't worry too much about it, though. It's already done for you by virtue of the fact that the boxes you affix to metal framing are bonded.
 
What if you use plastic boxes? I can see that being a problem. Can we assume that the metal studs are bonded by the panelboard installed in the metal framing? It is likely to be energized, so it does need to be bonded correctly.

Tom
 
I've never but was considering it if the cost difference made it worthwhile. I might need 1500-2000 boxes soon. Residential, then again I'll probably just use metal.

Tom
 
I know that the people at Smart Box are pushing their boxes pretty hard for NM wiring on metal studs. They work pretty well. Box fill becomes an issue with their boxes, however. At about a buck a piece, it's worth a hard look.
 
These look good but I'm worried about the "flop"!

Tom

Would a continuity check be suffice in the situation?(Metal Framing to EGC)
 
au contrare. I am refering to Rx in metal framing with plastic boxes. Very commonplace in Southwest Fla. With this system, at least one box in each metal frame section not continuios with all the framing will have to be a metal box. The question is, how do you deal with the fact that the box is attached to the metal stud with a sheet matel framing screw and not a machine screw as required for bonding??? inquireing minds want to know. The inspector will be responcible for looking at the total framing system to insure that any framing with wiring runing thru it is bonded.
 
I understand what your saying, what kind of plastic boxes do you use? I think in my situation the bonding will be taken careof by the building. All steel trusses, steel strapping(U-channel), and steel studs used in this behemoth(40+ units), big for me anyways.


Tom
 
Picture concrete block exterior walls, wood trusses, and metal stud interior walls. Some knee walls, some independent self standing walls, room deviders
 
Steel studs are not required to be bonded by the NEC as they are not "exposed structural metal". 250.104(C).
Don
 
Cavie,

I would think that the point of bonding would be in the metal box, where the

machine screw would be used, after that all the screws would be sheet metal
 
Mike Holt has a graphic that shows metal studs, plastic boxes and one metal box that does the bonding
I have heard based on a death in FL that the 2008 NEC may require bonding of metal studs.
 
mdskunk, i did a job that had metal studding that we used plastic boxs on in a big residential job. then we had to bond the studs.the inspector insisted we bond the studs like a frigan pool with a #8.
 
cloudymacleod said:
mdskunk, i did a job that had metal studding that we used plastic boxs on in a big residential job. then we had to bond the studs.the inspector insisted we bond the studs like a frigan pool with a #8.
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That sounds like an inspector that never saw metal studs before.
 
don_resqcapt19 said:
Steel studs are not required to be bonded by the NEC as they are not "exposed structural metal". 250.104(C).
Don
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Would 250.4(A)(4) apply? Or is this an inspectors call.


Tom
 
Tom,
Would 250.4(A)(4) apply? Or is this an inspectors call.
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Yes it would be the AHJ call based on this code section. It is my opinion that while it is possible that the metal studs would be come energized, it is not likely.
Don
 
tom baker said:
Mike Holt has a graphic that shows metal studs, plastic boxes and one metal box that does the bonding
I have heard based on a death in FL that the 2008 NEC may require bonding of metal studs.
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Tom, was that incident in Fl. due to a home owner installing a metal medicine cabinet to metal studs that were energized ?
 
Cavie, Here is the section in the FBC specifying the requirement. The change can be found with the 2006 supplement. (The rule applies to ALL occupancy types)

Section 2704:
Bonding Metal Framing Members: Metal framing members. Metal framing members shall be bonded to the equipment grounding conductor for the circuit that may energize the framing and be sized in accordance with the National Electric Code Table 250.122. For the purpose of this section, a grounded metal outlet box attached to the framing shall be permitted.
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The main driving force behind this was the death of an appliance installer that was electrocuted after coming in contact with an energized metal dryer vent box. The individual that installed a bathroom medicine cabinet used 2" screws, which passed through the metal stud and into an NM cable running parallel with the metal stud. This energized the entire wall section and the dryer duct box, which happened to be attached to the same wall section
 
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