Grounding vs Bonding Online Training

This article was posted 05/19/2006 and is most likely outdated.

Grounding vs Bonding: 250.100 Bonding—Hazardous (Classified) Locations

May 19, 2006

View Comments | Add Comments | Notify Me When Comments Are Added

PART V. BONDING

VIEWING Video FILE requires
Real Media Player [ FREE ]

Sections

250.100 Bonding—Hazardous (Classified) Locations.

Because of the explosive conditions associated with electrical installations in hazardous (classified) locations, electrical continuity of the effective ground-fault current path (metal parts of equipment and raceways) must be ensured by one of the methods specified in 250.92(B)(2) through (4): Figure 250–142

Author’s Comments:
• The methods of bonding metal raceways that extend into a hazardous (classified) location include:
• Threaded couplings or threaded entries on enclosures [250.92(B)(2)].
• Threadless raceway couplings and connectors where permitted in Articles 501, 502, and 503 [250.92(B)(3)].
• Bonding the raceway with a listed bonding wedge or bushing [250.92(B)(4)].
• Bonding the raceway with a bonding-type locknut if the metal raceway terminates to an enclosure without a ringed knockout [250.92(B)(4)].

• Hazardous (classified) location bonding requirements apply to all intervening raceways, fittings, boxes, and enclosures between the hazardous (classified) location and the point of grounding and bonding at service equipment and separately derived systems. See 501.100 for Class I locations, 502.100 for Class II locations, and 503.100 for Class III locations for specific requirements. Figure 250–143

Send to a Friend

Figure 250–142
(Click on image to enlarge)

Figure 250–143
(Click on image to enlarge)

Comments

Almost all if not all gasoline station equipment manufacturers require and insulated green copper redundant equipment grounding wire in the raceways and wireways that supply their equipment. They also require all conduits to have insulated throat grounding bushings at both ends of each branch circuit raceway.

The British require a redundant grounding conductor in all metal conduits in all occupancies and not just in hospitals like over here. I have opened up enough walls enough times ( once ) to know why they require this.

Also, I have repaired quite a few conduits in factories where the joints broke because of machine vibration or somebody NOT watching what they are doing with a forklift truck.

Mike Cole, mc5w at earthlink dot net

Michael R. Cole

Reply to this comment


* Your Name:	Your name will appear under your comments.
* Your Email:	Your email address is not displayed.
* Comments:	Email Notification Options: Notify me when a reply is posted to this comment Notify me whenever a comment is posted to this newsletter