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Joined: Oct 2000
Posts: 2,749
Just to be sure, you should read the following information very carefully, when evaluating concentric and eccentric knockouts:

Joe Tedesco, NEC Consultant
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Joined: Feb 2003
Posts: 27
Intresting have you seen any boxes or cabinets marked? I will be looking for them but I still probably still bond bush so not to upset an inspector who hasn't seen the marking, plus just assurance that it is bonded and be ease of mind.

William Runkle
Joined: Oct 2000
Posts: 2,749

The following table summarizes the box and enclosure categories where such an evaluation is available and how to identify compliant products that can be installed according to the exception to Section 250.97.

Category Code
Product Category
Concentric and eccentric knockouts evaluated for bonding?

Boxes, Junction and Pull
Only when product is marked*

Cabinets and Cutout Boxes
Only when product is marked*

Metallic Outlet Boxes
All products comply

* Products Listed for these applications are provided with a marking, such as "Concentric (or eccentric) knockouts suitable for bonding conduits for non-service conductors."

Joe Tedesco, NEC Consultant
Joined: Jun 2003
Posts: 1,143
+1 for the additional bonding.

The $8 in parts is worth more than 20 minutes proving your point to an inspector.

Joined: Dec 2004
Posts: 94
tkb Offline
Just knock out the KO all the way and use reducing washers. They are UL listed for grounding. Save the cost of the bond bushings.

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