transformer reverse wiring - Electrician Talk - Professional Electrical Contractors Forum
Go Back   Electrician Talk - Professional Electrical Contractors Forum > Electrical Trade Topics > Services and Service Equipment

Thread Tools Display Modes
Old 10-09-2007, 08:48 PM   #1
Junior Member
Join Date: Oct 2007
Posts: 1
Rewards Points: 10
Default transformer reverse wiring

This concerns delta corner grounding
I have a 480 - 120/208 transformer.
I want to derive 480 volts.
I will feed a 30 kva with a 90 amp breaker and feed the L 123 lugs
I then will take H 123 for my load.
My question is do I corner ground one of the 3 H legs to produce stable voltage readings?
challenge electric is offline   Reply With Quote
Join Contractor Talk

Join the #1 Electrician Forum Today - It's Totally Free! - Are you a Professional Electrical Contractor? If so we invite you to join our community and see what it has to offer. Our site is specifically designed for you and it's the leading place for electricians to meet online. No homeowners asking DIY questions. Just fellow tradesmen who enjoy talking about their business, their trade, and anything else that comes up. No matter what your specialty is you'll find that is a great community to join. Best of all it's totally free!

Join - Click Here JOIN FOR FREE

Warning: The topics covered on this site include activities in which there exists the potential for serious injury or death. DOES NOT guarantee the accuracy or completeness of any information contained on this site. Always use proper safety precaution and reference reliable outside sources before attempting any construction or remodeling task!

Sponsored Links
Old 10-10-2007, 05:48 PM   #2
Senior Member
brian john's Avatar
Join Date: Mar 2007
Location: Gilbert's Corner VA
Posts: 26,370
Rewards Points: 1,782

[quote]I will feed a 30 kva with a 90 amp breaker and feed the L 123 lugs
I then will take H 123 for my load. [quote]

I assume you mean X1, X2. X3 are 208 (no neutral/grounded conductor)and H1, H2, H3 480 VAC?

That is up to you the NEC does not require it.

BUT IMO, this is a bad installation. I speak from a multitude of experience, where contractors call my shop to check out WIERD voltages at a facility we get there, and we find this connection. In addition some transformer manufactures do not list their transformer for reverse feeding. Lastly there is a higher inrush on the 208 VAC side then there would be on a 208 delta to 480/277 Wye due to winding design They make the right transformer for the application, why not use it? 208 Delta to 480/277 Wye.
brian john is online now   Reply With Quote

Thread Tools
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off

Similar Threads
Thread Thread Starter Forum Replies Last Post
Trouble shoot hot ground reverse pmg General Electrical Discussion 6 10-16-2008 08:38 AM
Transformer? preacher General Electrical Discussion 7 10-02-2008 08:23 PM
Transformer wiring boyzrus Services and Service Equipment 6 08-13-2008 11:23 PM
transformer sizing ???? Vr_ecobox Services and Service Equipment 1 12-07-2007 07:49 PM
transformer DBack Elec General Electrical Discussion 2 11-29-2007 09:28 AM

All times are GMT -4. The time now is 08:48 AM.

Powered by vBulletin® Version 3.8.8
Copyright ©2000 - 2017, vBulletin Solutions, Inc.
Search Engine Optimization by vBSEO 3.6.1
vBulletin Security provided by vBSecurity v2.2.2 (Pro) - vBulletin Mods & Addons Copyright © 2017 DragonByte Technologies Ltd.
User Alert System provided by Advanced User Tagging (Pro) - vBulletin Mods & Addons Copyright © 2017 DragonByte Technologies Ltd.
Our Pro Sites Network | | | | |