ECN Electrical Forum - Discussion Forums for Electricians, Inspectors and Related Professionals
ECN Shout Chat
Shout Box
Recent Posts
Inspection camera help
by petey_c. 09/22/18 07:52 AM
Motion detectors and dimmers
by gfretwell. 09/20/18 04:02 PM
Extension cords
by annemarie1. 09/20/18 08:54 AM
220/230/240V 60Hz Systems
by gfretwell. 09/16/18 12:37 PM
Acronis Backup 2017
by gfretwell. 09/16/18 12:46 AM
New in the Gallery:
Plug terminals
Housebilding DIY wiring
Who's Online Now
0 registered members (), 31 guests, and 26 spiders.
Key: Admin, Global Mod, Mod
Previous Thread
Next Thread
Print Thread
Rate Thread
secondary neutral #63103
03/06/06 08:45 PM
03/06/06 08:45 PM
circuit man  Offline OP
Joined: Nov 2001
Posts: 273
ok here is one that really has me have a 3 phase 14400 volt primary with no feed a single phase dual bushing 7.2/14.4 pri to 120/240 secondary transformer. where do you get the system neutral? i know that the secondary has a midpoint & is also grounded to the can & pole. but what keeps this in line so to speak? THANKS!

Work Gear for Electricians and the Trades
Re: secondary neutral #63104
03/06/06 09:03 PM
03/06/06 09:03 PM
e57  Offline
Joined: May 2003
Posts: 2,876
"i know that the secondary has a midpoint & is also grounded to the can & pole."
You answered your own question....

"but what keeps this in line so to speak?"
From floating nuetral? There could be some float due to sever phase unbalace, but not by much.

Mark Heller
"Well - I oughta....." -Jackie Gleason
Re: secondary neutral #63105
03/07/06 01:48 AM
03/07/06 01:48 AM
wa2ise  Offline
Joined: Nov 2002
Posts: 787
Oradell NJ USA
It doesn't really matter what the primary side is doing. But all you really want and need is good grounding of your neutral on the secondary side. That gets done at the pole, and also all the service entrances.

If the secondary wasn't tied to ground, capacitive coupling thru the transformer to the primary would create a substantial fraction of the primary voltage to appear on the secondary. Relatively high impedance, but more than enough to electrocute someone.

Re: secondary neutral #63106
03/08/06 05:09 AM
03/08/06 05:09 AM
pauluk  Offline
Joined: Aug 2001
Posts: 7,520
Norfolk, England
Different voltage levels, but that's how all our transformers are wired in England, as we never have a neutral distributed with the HV lines.

Re: secondary neutral #63107
03/08/06 12:36 PM
03/08/06 12:36 PM
Radar  Offline
Joined: Apr 2004
Posts: 349
Los Angeles, CA
where do you get the system neutral? . . . i know that the secondary has a midpoint & is also grounded

The grounded mid-point is your neutral, by definition. No (intended) connection between the primary and the secondary electrical systems.


There are 10 types of people. Those who know binary, and those who don't.


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


Member Spotlight
Anaheim, CA. USA
Posts: 2,708
Joined: October 2000
Show All Member Profiles 
Top Posters(30 Days)
Admin 13
Trumpy 11
Popular Topics(Views)
249,378 Are you busy
187,310 Re: Forum
176,653 Need opinion
Powered by UBB.threads™ PHP Forum Software 7.6.1
(Release build 20180101)
Page Time: 0.015s Queries: 14 (0.003s) Memory: 0.9684 MB (Peak: 1.1075 MB) Zlib enabled. Server Time: 2018-09-22 21:26:22 UTC