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!


2017 NEC and Related
2017 NEC
Now Available!

Recent Posts
Parking lot pole light swap....
by gfretwell
Yesterday at 09:52 PM
International Wire Colour Codes
by Texas_Ranger
Yesterday at 08:24 AM
Son of Sparky
by HotLine1
10/20/16 07:43 PM
Speaking of Plugmold ...
by gfretwell
10/17/16 02:37 PM
Broken battery charger? Check for cobwebs!
by gfretwell
10/17/16 02:30 PM
New in the Gallery:
12.5A through 0.75mm˛ flex (just out of curiosity)
Shout Box

Top Posters (30 Days)
gfretwell 12
renosteinke 6
HotLine1 6
ghost307 5
Potseal 4
Who's Online
1 registered (geoff in UK), 213 Guests and 4 Spiders online.
Key: Admin, Global Mod, Mod
Topic Options
Rate This Topic
#164008 - 05/22/07 08:22 PM Grounding Transformer
Cinner Offline

Registered: 12/01/04
Posts: 77
Loc: Kelowna, B.C., Canada
Can you ground a transformer to a steel column of a steel building or do you have to run the ground wire to a system ground?

2014 / 2011 NEC & Related Books and Study Guides
#164039 - 05/23/07 02:28 PM Re: Grounding Transformer [Re: Cinner]
Sandro Offline

Registered: 12/30/01
Posts: 449
Loc: Stoney Creek, ON, Canada
Ontario code allows it, provided the steel building is bonded at two separate points to ground using the same size ground wire as the main service.

This is a very handy practice, say, in a machine shop that use a separate transformer for each piece of equipment.

#164070 - 05/24/07 08:47 AM Re: Grounding Transformer [Re: Cinner]
mikesh Offline

Registered: 06/07/06
Posts: 614
Loc: Victoria, BC, Canada
My quick answer is no. there are circumstances where i would allow it but only if it can be easily proven that the building steel is continuous and solidly connected to the grounding system and electrodes. 10-700 mentions in-situ electrodes and defines what that might be. In buildings where the engineering required the steel to be bonded in 2 widely seperated places (very old code for High voltage substation grounding) and was made continuous via bonding jumpers, welding, or mechanical joints proven to be electrically continuous then we might allow the column to be part of the system ground. A lot of homework to do in an old building but might be simple to establish when the power distributution is planned and the bonding and grounding is included in the inspections of the building. The long answer is maybe.


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