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)
241,449 Are you busy
177,433 Re: Forum
169,015 Need opinion
Who's Online Now
0 registered members (), 50 guests, and 13 spiders.
Key: Admin, Global Mod, Mod
Previous Thread
Next Thread
Print Thread
Rate This Thread
#13670 - 09/09/02 01:57 PM 3-Wire Range and Dryer History  
Electra  Offline
Member
Joined: Jul 2002
Posts: 38
Portland, Oregon, USA
I was just curious if anybody knew the history of why it took so long to change the requirements for ranges and dryers from 3-wire to 4-wire hookup.


Work Gear for Electricians and the Trades

#13671 - 09/11/02 10:49 PM Re: 3-Wire Range and Dryer History  
The Watt Doctor  Offline
Member
Joined: Dec 2001
Posts: 435
Mont Belvieu, TX
Electra,
Check out this thread . You might ask Creighton.
Good Luck,
Doc


The Watt Doctor
Altura Cogen
Channelview, TX

#13672 - 09/12/02 11:36 AM Re: 3-Wire Range and Dryer History  
Creighton  Offline
Member
Joined: Jan 2002
Posts: 59
Hayward, CA
prior to the 1947 NEC equipment could be grounded to the grounded conductor only by special permission. In Sec. 2560 in the 1947 NEC it was specifically permitted to ground an electric range to the grounded conductor. This could result in a small voltage between the range frame and adjacent grounded surfaces, but was rarely a problem. It is my understanding that in 1947 the Utilities were interested in building load, and to make range installation less costly the 3-wire rather than 4-wire connection was permitted. One argument in favor is that if the grounding conductor to a range is open there will be no indication of it until it is needed, but with the old 3-wire connection if the neutral is open the clock does not work, the oven light does not work, and it is obvious that something is wrong, and it will be repaired. Now only existing 3-wire range outlets are permitted, new installations requiring 4-wire.
The 3-wire concept was extended to dryers. If you need to know when, I will look it up.
Hope this helps. Creighton



Member Spotlight
waymag
waymag
dallas, texas, USA
Posts: 67
Joined: January 2002
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: 0.012s Queries: 14 (0.004s) Memory: 0.7511 MB (Peak: 0.8757 MB) Zlib enabled. Server Time: 2017-10-23 00:51:25 UTC