ECN Electrical Forum - Discussion Forums for Electricians, Inspectors and Related Professionals
ECN Shout Chat
Top Posters(30 Days)
Recent Posts
VFD MotorFeeders
by gfretwell. 10/19/17 01:02 AM
Generator Cable Sizing
by brsele. 10/18/17 07:39 PM
What do you do?
by gfretwell. 10/17/17 01:08 AM
Good ol' copper pipe in the fuse holder trick
by HotLine1. 10/16/17 07:16 PM
Another generator question
by HotLine1. 10/16/17 07:02 PM
New in the Gallery:
Gallery Test
Popular Topics(Views)
241,387 Are you busy
177,342 Re: Forum
168,954 Need opinion
Who's Online Now
0 registered members (), 34 guests, and 12 spiders.
Key: Admin, Global Mod, Mod
Previous Thread
Next Thread
Print Thread
Rate This Thread
#217353 - 06/23/16 02:10 AM Outdoor transformer/grounding question  
Sparky42  Offline
New Member
Joined: Jun 2016
Posts: 2
CA
Application is an outdoor 30kVA, 480V/400V step down delta-wye transformer to be located within 10 feet of a building panel breaker box. The box has three phase 480V fused power and an input ground wire tied to the breaker box via a screw lug. The output is a 3P4W IEC-309 receptacle, the ground pin of the receptacle has a wire that screws into the breaker box. My question is: Can I use the receptacle ground wire to be the ground for the transformer chassis and X0 of the secondary (via a terminal bar inside and bonded to the transformer enclosure)? Or will I have to run a ground wire independent of the receptacle so that ground is always made regardless of if the plug is in the receptacle. I could not find this detail in NEC.


2017 / 2014 NEC & Related Books and Study Guides

#217354 - 06/23/16 03:20 AM Re: Outdoor transformer/grounding question [Re: Sparky42]  
gfretwell  Offline


Member
Joined: Jul 2004
Posts: 9,123
Estero,Fl,usa
I suppose you need to back up and see if that transformer is listed for cord and plug connection. If that is OK, I suppose the pin in the plug is sufficient to establish the ground.
Those 309 plugs are designed so the ground makes before the ungrounded pins.


Greg Fretwell

#217387 - 07/01/16 12:59 AM Re: Outdoor transformer/grounding question [Re: Sparky42]  
Yoopersup  Offline
Member
Joined: Mar 2003
Posts: 830
Michigan
Read 2014 N.E.C. 250.30 (C)


#217393 - 07/05/16 12:09 AM Re: Outdoor transformer/grounding question [Re: Sparky42]  
Sparky42  Offline
New Member
Joined: Jun 2016
Posts: 2
CA
Hmmm, the breaker box is mounted on a metal building. Can I consider the breaker box as the source location? In that case there is a ground wire connected to the breaker box itself (and it comes out via the IEC-309 connector). This is not a permanent installation it will only be active for a month or so.



Member Spotlight
Attic Rat
Attic Rat
Bergen Co.,N.J. USA
Posts: 524
Joined: December 2003
Show All Member Profiles 
Featured:

2017 Master Electrician Exam Preparation Combos
2017 NEC Electrician
Exam Prep Combos:
Master / Journeyman

 

Shout Box
Powered by UBB.threads™ PHP Forum Software 7.6.0
Page Time: 0.015s Queries: 15 (0.003s) Memory: 0.7600 MB (Peak: 0.8907 MB) Zlib enabled. Server Time: 2017-10-19 07:26:40 UTC