ECN Electrical Forum - Discussion Forums for Electricians, Inspectors and Related Professionals
ECN Shout Chat
ShoutChat
Recent Posts
Danish type K Sockets
by winston_1 - 10/25/21 07:30 PM
Flexible Conduit?
by gfretwell - 10/24/21 01:59 AM
May I backfeed 3 phase transformer?
by dsk - 10/22/21 04:37 AM
Wire sizing
by gfretwell - 10/21/21 10:12 PM
GFCI's pops in large numbers
by dsk - 10/21/21 02:03 AM
New in the Gallery:
240/208 to a house
240/208 to a house
by wa2ise, October 9
Now you know.
Now you know.
by Tom_Horne, September 7
Who's Online Now
0 members (), 36 guests, and 16 robots.
Key: Admin, Global Mod, Mod
Previous Thread
Next Thread
Print Thread
Rate Thread
#206734 08/04/12 12:26 PM
Joined: Jul 2002
Posts: 241
S
SJT Offline OP
Member
In regard to threaded grounding bushings (with grounding lug on it), where are these to be installed?
I was checking 250.97 and 300.4(G) in the code.
If possible, could you refer me to the code sections, where we must install such bushings, as compared to normal bushings?
Just trying to have code references, so we don't install ground bushings where they are not needed.
Thanks - Good day
SJT

2017 / 2014 NEC & Related Books and Study Guides
SJT #206739 08/04/12 10:54 PM
Joined: Jun 2004
Posts: 1,273
T
Member
The SINGLE most common use for such grounding bushings is at the terminus of an EMT, GRC, IMC, Flex shielded run on a GEC -- wherever its headed.

Sometimes I've installed them as a grounding lug even with a naked bare GEC system bonding conductor.

Other than that, they've got little purpose.

They are never used to replace lazy-lugs/ lay-in lugs.

And they are typically UL listed for conductor size -- maxxed at 3/0 -- the largest GEC from the table.

That's one hint from the manufacturer/ UL as to their purpose -- they're choke eliminators -- and the inspector will be looking for them on all GEC bonding runs that are wrapped in steel pipe/ steel flex.

They are NOT required if the same run is wrapped in PVC.

As for GEC Systems, the NEC Handbook has sweet illustrations. Exhibit 250.32 [ BTW, the bushing is normally attached physically to the raceway -- but it doesn't absolutely have to -- see the diagram.

NEC 250.64.E

NEC 250.104

Happy to post the citations for the forum...

(2005 copy...)


Tesla

Link Copied to Clipboard
Featured:

Tools for Electricians
Tools for Electricians
 

* * * * * * *

2020 Master Electrician Exam Preparation Combos
2020 NEC Electrician
Exam Prep Combos:
Master / Journeyman

 

Member Spotlight
pcsailor
pcsailor
Minneapolis, MN, USA
Posts: 21
Joined: September 2019
Top Posters(30 Days)
dsk 7
wa2ise 1
Popular Topics(Views)
284,930 Are you busy
217,466 Re: Forum
203,765 Need opinion
Powered by UBB.threads™ PHP Forum Software 7.7.5