electrically conductive matreials

[ins.GDF]

Is it common practice to bond metal ductwork to satisfy 250.4(A)(4)

 

[raider1]

Unless there is a isolation boot on the ductwork it would be bonded by default by the equipment grounding conductor run to the funace.

I don't see anybody running a separate bonding conductor to metal duct.

Chris

 

[dcspector]

Is it common practice to bond metal ductwork to satisfy 250.4(A)(4)

Not really as far as common practice. Also, see 250.104(B) and see the FPN: What is likely to become energized? I have seen a large amount of NM in contact with metal ductwork, yes it would be a good idea to bond it as an example. Ie....one nick in the grounded conductor under a load would enregize the metal ductwork....as an example only.