ECN Electrical Forum - Discussion Forums for Electricians, Inspectors and Related Professionals
ECN Shout Chat
Top Posters(30 Days)
Recent Posts
VFD MotorFeeders
by Yoopersup. 10/22/17 07:52 PM
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)
241,452 Are you busy
177,435 Re: Forum
169,017 Need opinion
Who's Online Now
0 registered members (), 59 guests, and 16 spiders.
Key: Admin, Global Mod, Mod
Previous Thread
Next Thread
Print Thread
Rate This Thread
Page 1 of 2 1 2
#12824 - 08/18/02 07:19 AM Male attachment plug prongs  
jes  Offline
Member
Joined: Jul 2002
Posts: 103
CT
OK, here's a trivia question.
Why do male attachment plug prongs (some, not all) have round holes through them near the ends??? I DON'T know the answer!!


Work Gear for Electricians and the Trades

#12825 - 08/18/02 08:04 AM Re: Male attachment plug prongs  
walrus  Offline
Member
Joined: Jul 2002
Posts: 680
Bangor Me. USA
Lockout, tagout?


#12826 - 08/18/02 11:34 AM Re: Male attachment plug prongs  
NJwirenut  Offline
Member
Joined: Sep 2001
Posts: 806
Bergen County, NJ
Helps hold the plug into the receptacle. There is a corresponding "dimple" in the contact spring, which "locks" into the hole in the plug blade.


#12827 - 08/18/02 11:54 AM Re: Male attachment plug prongs  
sparky66wv  Offline
Member
Joined: Nov 2000
Posts: 2,236
West Virginia
And here I thought they were to clean the contacts...?

Makes sense though...


-Virgil
Residential/Commercial Inspector
5 Star Inspections
Member IAEI

#12828 - 08/18/02 04:33 PM Re: Male attachment plug prongs  
pauluk  Offline
Member
Joined: Aug 2001
Posts: 7,520
Norfolk, England
Don't forget that the holes also make it easy to wrap bare wires for Mexican-style extension cords.... [Linked Image]


#12829 - 08/18/02 07:45 PM Re: Male attachment plug prongs  
jes  Offline
Member
Joined: Jul 2002
Posts: 103
CT
Interesting comments but:
The holes have been there a LONG time... long before lockout/tagout came on the scene, however I have seen some loto devices that use the holes.
The contact idea is interesting but I've never seen a receptacle with contact strips having dimples...
A cleaning function is interesting...could be!
Still searching!


#12830 - 08/18/02 09:53 PM Re: Male attachment plug prongs  
Anonymous
Unregistered

I was told back in school that a long time ago receptacles had little spring loaded balls that would engage those holes.


#12831 - 08/19/02 07:48 AM Re: Male attachment plug prongs  
Trainwire  Offline
Member
Joined: Mar 2002
Posts: 360
Strasburg,PA,USA
My bet is that they are part of the manufacturing process, like maybe how they are hung onto when they mold the plug around them.
Trainwire


#12832 - 08/19/02 08:05 AM Re: Male attachment plug prongs  
Texas_Ranger  Offline
Member
Joined: Dec 2001
Posts: 2,402
Vienna, Austria
I've got a 1970ies Sony stereo with NEMA plug and an unswitched outlet. When I push in a plug I can feel that the prongs get locked when fully inserted.
BTW, I was close to using the mexican style cord. I replaced a light switch in a room without a window, so I needed some temporary lighting. The only thing I could find was an imported US table lamp with an adaptor which has been hooked up forever in our living room. When I tried to hook it up I nearly got a fit. The adaptor was as stone aged as the lamp and it wouldn't fit Schuko receptacles! Finally I pulled two (illegal) ungrounded extension cords through the appartment and hooked my lamp up. SO much about being able to stick to codes...


#12833 - 12/04/06 06:13 AM Re: Male attachment plug prongs  
Luketrician  Offline
Member
Joined: Jul 2006
Posts: 272
Sale Creek, TN USA
Quote
Don't forget that the holes also make it easy to wrap bare wires for Mexican-style extension cords....


I'm not an old timer on this site but I bet there are some pics of this in the violation photo forum. I've seen that practice done plenty of times, unfortunately. [Linked Image]

Luke


Luke Clarke
Electrical Planner for TVA.


Page 1 of 2 1 2

Member Spotlight
Niko
Niko
Campbell, CA
Posts: 356
Joined: August 2006
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: 0.014s Queries: 15 (0.002s) Memory: 0.8145 MB (Peak: 0.9906 MB) Zlib enabled. Server Time: 2017-10-23 02:23:26 UTC