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Have you or someone you know ever cut the ground prong off of an extension or appliance cord?
Yes
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Not that I will admit
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 Post subject: Cut Ground Prong / Electrical Grounding / Electrical Safety
PostPosted: Sun Jan 20, 2013 1:07 pm 
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Joined: Mon Sep 17, 2007 5:00 pm
Posts: 1635
Location: Scottsdale, Arizona
Proper grounding to reduce the possibility of electric shock plays a very important role in electrical safety. Some have been known to cut the ground prong off of an extension or appliance cord in order to get a 3 prong cord into a two prong receptacle Of course this can be dangerous. This week’s question is pretty simple.

Have you or someone you know ever cut the ground prong off of an extension or appliance cord?
  • Yes
  • No
  • Not that I will admit :cool:

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PostPosted: Mon Jan 21, 2013 5:14 am 

Joined: Thu Mar 19, 2009 9:40 am
Posts: 19
Location: Wi
brainfiller wrote:
Proper grounding to reduce the possibility of electric shock plays a very important role in electrical safety. Some have been known to cut the ground prong off of an extension or appliance cord in order to get a 3 prong cord into a two prong receptacle Of course this can be dangerous. This week’s question is pretty simple.

Have you or someone you know ever cut the ground prong off of an extension or appliance cord?
  • Yes
  • No
  • Not that I will admit :cool:


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PostPosted: Mon Jan 21, 2013 5:16 am 

Joined: Thu Mar 19, 2009 9:40 am
Posts: 19
Location: Wi
I find at least one everytime I do an equipment grounding conductor check. No one ever seems to know how it happens.


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PostPosted: Mon Jan 21, 2013 6:15 am 
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Joined: Tue Feb 24, 2009 7:05 am
Posts: 252
At the local home improvement store, I saw a three-prong female to two-prong male adapter for sale. I asked a clerk (because I thought they had been pulled of the market a couple years ago), and he told me that those were legal because there was a small metallic part on the two-prong side which could contact the screw which holds the plastic plate. Not sure what kind of grounding you get from that, especially if the screw is painted (which is often the case) and the receptacle is not grounded (happens if you don't have a three-pring receptacle).


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PostPosted: Mon Jan 21, 2013 9:48 am 

Joined: Tue May 22, 2012 7:04 am
Posts: 6
Location: Mississauga, Ontario
It happens way too often, especially with Christmas lighting and extension cords that are not grounded that need to plugged into a non grounded plug( which you should not have) or an old ungrounded extension that you have laying around. GFCI will not work!


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PostPosted: Mon Jan 21, 2013 11:10 am 
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Joined: Wed Sep 01, 2010 1:11 pm
Posts: 11
In my early days of being a teenage rock star wanna-be and novice sound tech, a "ground isolation plug" was often used as the Thinking Man's : ) alternative to ripping the ground off of an extension cord, as was often done to rid the PA sound of a hum that resulted from a ground loop created whenever the sound board and pa amps were located up to 100 ft apart, were powered by different outlets/circuits, and connected together with audio connections that including a ground. Actually, we had no clue as to why the hum was present but the older music veterans were more than eager to teach us younglings the ways of being in a band. We were at least smart (lucky?) enough to make sure one section of gear remained earth-grounded, so that all gear was grounded, albeit through audio cable grounds -yikes. Not condoning it at all, just admitting it.

Through all that danger, the only times I ever "discovered" electricity was early on when I would be setting up for a show with my vintage 1965 Fender Deluxe Reverb, with its factory-installed 2-prong power cord and "Pain" switch in the rear of the amp near the power cord. After tiring of the stinging, pretty blue arcs that would often fly from my microphone to my lips I decided to carry a volt meter and test for voltage between my guitar strings and my microphone. If it read 115V, then I switched the switch in the rear and put a "fro" windscreen on the mic for good measure. Some minimal electrical education later I removed the switch and also installed an earth ground in the amp.

"There but for the grace of God,......"


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PostPosted: Mon Jan 21, 2013 11:29 am 

Joined: Wed Nov 07, 2012 5:34 pm
Posts: 13
@littlerocker has it exactly right. the induced ground potentials in some buildings can vary by up to 50 volts from one outlet to another. In one location, the lead singer took the protective foam off his mic to clean it and forgot to replace it. The jolt when lips touched the mic was enough to flatten him (he was also holding his electric guitar at the time). There was no alternative but to cut ground lugs off to eliminate this hazard.

For amusement sometime, take a voltmeter and an extension cord around your plant and measure the voltage between the ground pins in two receptacles located any significant distance apart. The results may shock you, especially if you have VFD's and electronic ballasts.

Another instance of cutting lugs off was with an older oscilloscope which had BNC test lead connectors which were mounted directly on part of the chassis frame. The entire scope became hot in order to perform the desired measurement. Fortunately the adjustment knobs were plastic! Of course, newer test equipment eliminates this issue.


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PostPosted: Fri Jan 25, 2013 3:49 pm 

Joined: Fri Aug 10, 2012 11:47 am
Posts: 17
Vincent- If used as intended the two prong to three prong "cheater plugs" do provide a ground. The small metal tab (or sometimes a green wire with a fork terminal) is supposed to be secured underneath the mounting screw on the outlet plate. Now, depending on how and when the receptacle was wired that screw may or may not be grounded. I live in a 100 year old house that was changed over from knob and tube to conduit in the 1950's and despite the majority of outlets being two prong they all have grounded metal boxes. (Lucky for me, Chicago and surrounding suburbs require metal conduit for both commercial and residential installations).

lsilecky- Interestingly enough, a standard outlet type GFCI will work without a ground. It monitors and detects if there is more current leaving the hot conductor than returning on the neutral. It does not monitor the ground current. For more information see Section 210-7(d)(3) (excerpt from EC&M website article below)

Sec. 210-7(d)(3) permits any of the following installations when replacing a 2-wire ungrounded receptacle:
(a) Replace it with another 2-wire receptacle;
(b) Replace it with a GFCI-type receptacle and mark the receptacle with the words “No Equipment Ground;” or
(c) Replace it with a grounding-type receptacle protected by a GFCI device (circuit breaker or receptacle). Since the grounding terminals for the receptacles are not grounded, you must mark the receptacles with the words “GFCI Protected” and “No Equipment Ground”


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PostPosted: Mon Jan 28, 2013 5:09 am 
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Joined: Wed Oct 29, 2008 6:06 am
Posts: 136
Location: Michigan
I've never actually seen it done, but we do often find them that way on extension cords during safety audits . We remove the cord from use and cut the plug off so that it cannot be used in that condition again. What we typically hear is either, "I don't know how that happened, it was that way when I got it, or it just broke off". (This is covered in our nonqualified electrical safety class.) Sometimes I think a lot of these extension cords come from outside contractors...


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