The Electrical Contractor Network

ECN Electrical Forum
Discussion Forums for Electricians, Inspectors and Related Professionals

Books, Tools and Test Equipment for Electrical and Construction Trades

Register Now!

Register Now!

We want your input!

Featured:
   

2017 NEC and Related
2017 NEC
Now Available!

   
Recent Posts
Sprinklered equipment 26-008
by bigpapa
Yesterday at 04:24 PM
On Delay Relay with Auto Reset
by Potseal
12/01/16 09:59 AM
Wow, that was close!
by jraef
11/28/16 07:06 PM
Earthquake in New Zeeland
by RODALCO
11/27/16 11:25 PM
Calling all Non-US members!! (Non-US only)
by Tjia1981
11/27/16 06:33 AM
New in the Gallery:
12.5A through 0.75mm˛ flex (just out of curiosity)
Shout Box

Top Posters (30 Days)
gfretwell 15
HotLine1 10
Trumpy 8
Texas_Ranger 8
sparkyinak 7
Who's Online
0 registered (), 101 Guests and 4 Spiders online.
Key: Admin, Global Mod, Mod
Topic Options
Rate This Topic
#14229 - 09/16/02 09:10 PM bonding
USELECTRIC Offline
Junior Member

Registered: 09/16/02
Posts: 3
Loc: Poughkeepsie, NY., USA
Do we have to bond the insulated grounding wire of MC cable to a metal box? Isn't the metal jacket enough? If so, what do you do in the case of an Isolated grounding receptacle? Mike

Top
Work Gear for Electricians and the Trades

Work Gear for Electricians and the Trades
Work Gear for Electricians and the Trades
Arc Flash Clothing, Gloves, KneePads, Tool Belts, Pouches, Tool Carriers, etc. etc....

#14230 - 09/17/02 03:55 AM Re: bonding
Redsy Offline
Member

Registered: 03/28/01
Posts: 2138
Loc: Bucks County PA
The jacket of standard sriral wound MC cable is not sufficient to provide grounding without supplemental grounding conductors.
See 250.118(11).
As far as your installation, there is an assortment of special MC cables available. This includes those that have additional grounding conductors.

BTW,
If you have a handbook, the commentary following 330.108 explains this situation.

[This message has been edited by Redsy (edited 09-17-2002).]

Top
#14231 - 09/17/02 04:05 AM Re: bonding
L.C. Ammons Offline
Junior Member

Registered: 09/16/02
Posts: 6
Loc: Baton Rouge, LA
The NEC does not allow the device (receptacle) to bond the box. Since the MC sheath is not rated for grounding, you must ground the green wire to the box. Here we use a green wire pigtail that comes with a #10 screw available a most any supply house. This screws to the tapped ground screw hole in the box. We use a special green wirenut with a hole in it that allows the green wire to be stripped out bare long enough to reach the receptacle after it leaves the wirenut.

Top
#14232 - 09/17/02 04:09 AM Re: bonding
L.C. Ammons Offline
Junior Member

Registered: 09/16/02
Posts: 6
Loc: Baton Rouge, LA
As for as using MC for IG installations, you can order MC cable with both a solid green conductor and a green/yellow stripe conductor. It's not really cost effective to use that cable. You might as well use conduit. MC comes in about any configuration you want. I believe you can get it in large feeder sizes as well. I am bidding a job that calls for weatherproof (pvc jacketed) #8 MC to run on the bottom of sewage treatment ponds to aereator motors!

Top



ECN Electrical Forums - sponsored by Electrical Contractor Network - Electrical and Code Related Discussion for Electrical Contractors, Electricians, Inspectors, Instructors, Engineers and other related Professionals