The Electrical Contractor Network

ECN Electrical Forum
Discussion Forums for Electricians, Inspectors and Related Professionals

Books, Tools and Test Equipment for Electrical and Construction Trades

Register Now!

Register Now!

We want your input!

Featured:
   

2017 NEC and Related
2017 NEC
Now Available!

   
Recent Posts
Calling all Non-US members!! (Non-US only)
by aussie240
Yesterday at 02:39 AM
Photo Upload Tutorial
by DanK
12/06/16 11:35 PM
Sprinklered equipment 26-008
by bigpapa
12/02/16 04:24 PM
On Delay Relay with Auto Reset
by Potseal
12/01/16 09:59 AM
Wow, that was close!
by jraef
11/28/16 07:06 PM
New in the Gallery:
12.5A through 0.75mm˛ flex (just out of curiosity)
Shout Box

Top Posters (30 Days)
gfretwell 13
HotLine1 9
Texas_Ranger 8
sparkyinak 7
Trumpy 6
Who's Online
0 registered (), 78 Guests and 4 Spiders online.
Key: Admin, Global Mod, Mod
Page 1 of 2 1 2 >
Topic Options
Rate This Topic
#12824 - 08/18/02 04:19 AM Male attachment plug prongs
jes Offline
Member

Registered: 07/12/02
Posts: 103
Loc: 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!!

Top
Work Gear for Electricians and the Trades

Work Gear for Electricians and the Trades
Work Gear for Electricians and the Trades
Arc Flash Clothing, Gloves, KneePads, Tool Belts, Pouches, Tool Carriers, etc. etc....

#12825 - 08/18/02 05:04 AM Re: Male attachment plug prongs
walrus Offline
Member

Registered: 07/25/02
Posts: 671
Loc: Bangor Me. USA
Lockout, tagout?

Top
#12826 - 08/18/02 08:34 AM Re: Male attachment plug prongs
NJwirenut Offline
Member

Registered: 09/15/01
Posts: 816
Loc: 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.

Top
#12827 - 08/18/02 08:54 AM Re: Male attachment plug prongs
sparky66wv Offline
Member

Registered: 11/17/00
Posts: 2339
Loc: West Virginia
And here I thought they were to clean the contacts...?

Makes sense though...
_________________________
-Virgil
Residential/Commercial Inspector
5 Star Inspections
Member IAEI

Top
#12828 - 08/18/02 01:33 PM Re: Male attachment plug prongs
pauluk Offline
Member

Registered: 08/11/01
Posts: 7693
Loc: Norfolk, England
Don't forget that the holes also make it easy to wrap bare wires for Mexican-style extension cords....

Top
#12829 - 08/18/02 04:45 PM Re: Male attachment plug prongs
jes Offline
Member

Registered: 07/12/02
Posts: 103
Loc: 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!

Top
#12830 - 08/18/02 06:53 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.

Top
#12831 - 08/19/02 04:48 AM Re: Male attachment plug prongs
Trainwire Offline
Member

Registered: 03/15/02
Posts: 364
Loc: 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

Top
#12832 - 08/19/02 05:05 AM Re: Male attachment plug prongs
Texas_Ranger Offline
Member

Registered: 12/17/01
Posts: 2343
Loc: 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...

Top
#12833 - 12/04/06 02:13 AM Re: Male attachment plug prongs
Luketrician Offline
Member

Registered: 07/08/06
Posts: 273
Loc: 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.

Luke
_________________________
Luke Clarke
Electrical Planner for TVA.


Top
Page 1 of 2 1 2 >



ECN Electrical Forums - sponsored by Electrical Contractor Network - Electrical and Code Related Discussion for Electrical Contractors, Electricians, Inspectors, Instructors, Engineers and other related Professionals