Open Ground

Reply

  #1  
Old 08-04-04, 12:28 PM
A.W.R.
Visiting Guest
Posts: n/a
Question Open Ground

I have been told by a home inspector that he "Observed an exterior
receptacle is not GFCI protected, & tests as an open ground"
Please explain what an open ground is & how to correct it.
 
Sponsored Links
  #2  
Old 08-04-04, 12:58 PM
Member
Join Date: Sep 2003
Location: Central New York State
Posts: 13,973
There have been numerous posts on this topic. I recommend that you do a search for "open ground" and look at the results. Those results will tell you all you need to know and then some.

An open ground means that the ground hole on a three hole recepticle is open. Open means not connected to anything.

If you want to correct this, you need to determine why there is no ground. It could be old wiring, installed before grounds were common. It could be that the ground wire is not connected properly to the recepticle.
 
  #3  
Old 08-04-04, 01:16 PM
Member
Join Date: Feb 2002
Location: port chester n y
Posts: 2,117
Any Grounding -type ( 3-slot) receptacle is required to have it's Ground-terminal ( Green terminal) connected to an Equiptment Grounding Conductor ( EGC).

The 2 most common types of EGC's are the metallic armor of Armored Cable, and the bare EGC of a Non-metallic cable.

For your situation, much depends on the type of cable that encloses the conductors that connect to the receptacle. You will have to examine inside the outlet-box to make this determination. If its a metallic outlet-box, look for a metal connector or clamp that fastens a metallic cable to the O-B. You MAY have a non-metallic cable with only 2 conductors, which means there is no EGC.

This location requires GFI protection. This outlet MAY have GFI protection by being connected to the "Load" side of a GFI receptacle in another location-- so search for such a receptacle.

Please advise us on what you find-

Good Luck & Enjoy the Experience!!!!!!!!!!!
 
  #4  
Old 08-04-04, 01:17 PM
Member
Join Date: Sep 2000
Location: United States
Posts: 18,497
The tester that the home inspector carries around with him cannot detect both an open ground and the lack of ground fault protection. So all he really knows is the you have an open ground. He has no idea whether this receptacle is GFCI protected or not. But he expressed concern that maybe it was not. At least he couldn't test for it. He may not even understand the difference. Many home inspectors don't know that that tester cannot test for GFCI when there is an open ground. But that doesn't mean that it isn't there.
 
  #5  
Old 08-04-04, 03:21 PM
COBALT's Avatar
Member
Join Date: Jul 2004
Posts: 176
...unless he has access to the breaker panel and knows what breaker the circuit is on. If the breaker isn't GFCI protected for everything on that circuit then he knows. As for the open ground if a metal outlet box was used the ground wire may have been tied to the box but not the outlet. It happens....sloppy wiring.
 
  #6  
Old 08-04-04, 05:18 PM
Member
Join Date: Sep 2000
Location: United States
Posts: 18,497
Not sure I follow you Cobalt. The receptacle could easily be GFCI protected and yet there be absolutely no way to tell from the panel.
 
  #7  
Old 08-04-04, 05:43 PM
Member
Join Date: Sep 2003
Location: Central New York State
Posts: 13,973
PATTBAA,

"Any Grounding -type ( 3-slot) receptacle is required to have it's Ground-terminal ( Green terminal) connected to an Equiptment Grounding Conductor ( EGC)."

This statement is not correct. You can have a three prong recepticle on a two wire circuit, as long as the circuit is GFCI protected.

And of course, GFCI protection may not have been required when the recepticle was originally wired, although it should have been updated to include it, especially since a recepticle with ground was installed.
 
  #8  
Old 08-05-04, 09:11 AM
COBALT's Avatar
Member
Join Date: Jul 2004
Posts: 176
...I'm talking the other way around. Basic duplex receptacle but the entire circuit is protected by a GFCI breaker in the panel. I know it's not likely, but....that would be the only time you'd know for sure a standard outlet receptacle was GFCI protected just by inspection.
 
  #9  
Old 08-05-04, 09:20 AM
Member
Join Date: Feb 2002
Location: port chester n y
Posts: 2,117
I have erred on the side of saftey----

I'd be reluctant to suggest to anyone that it's possible to connect an exterior receptacle without a connection to the receptacle Ground-terminal. I'd advise anyone who is confronted with an exterior outlet-box connected to a cable that can't be used for Grounding the receptacle to abandon the outlet.

The GFI device must "sense" a current un-balance in the 2 Branch-Circuit conductors. If there is "leakage" in a tool that is properly Grounded, there is current thru the Grounding-path that will un-balance the current and "trip" the GFI device. A tool with a 3-wire cord plugged into a 3-wire extension cord which is plugged into a 3-wire Grounding receptacle WITHOUT a Grounding connection has an un-complete Grounding-path for any "leakage" current.

With an "open"-connection at the GFI Grounding-terminal, what "path-to-Ground" would cause a GFI device that is "protecting" tools plugged into extension-cords to operate?.
 
  #10  
Old 08-05-04, 11:26 AM
Member
Join Date: Sep 2000
Location: United States
Posts: 18,497
GFCI is very commonly used on ungrounded circuits. For personal protection, a GFCI without grounding is safer than a non-GFCI with grounding. If you ask people to abandon ungrounded receptacles, many people would have to abandon their entire house.

I would have no hesitation in using an ungrounded GFCI-protected receptacle. After all, you don't care as much about a leak to ground through the grounding wire as you care about a leak to ground through your body. The GFCI protects you from the latter perfectly fine without a grounding wire.
 
  #11  
Old 08-05-04, 12:51 PM
Member
Join Date: Feb 2002
Location: port chester n y
Posts: 2,117
"You care about a leak thru your body"--- that's exactly my argument.


Premise--- When the switch on a power-tool with a metal frame is operated, there is a very low impedance Ground-fault between the Un-grounded circuit-conductor and the metal frame of the tool. If someone operates this tool, via an extension cord, when standing on an aluminum ladder bearing against a Grounded metal surface, there are 2 paths for "leakage" current IF there is a Grounding-path with a very low impedance.This obviously requires that the Grounding terminal of the receptacle be connected to an EGC at the outlet.

With an effective, low-impedance Grounding-path, any leakage-current thru the metal frame will flow "back to the source", and minimal, if any leakage-current will flow thru the 2nd. path-- the person operating the tool.Without the Grounding path, the ONLY path is thru the tool-operator.

Certain Ground-faults thru tools can trip the circuit-breaker and open the circuit without GFI protection in the circuit IF there is a low-impedance Ground-path between the tool and the "source" to conduct the Fault-current back to the "source". But An "open" in the Ground-path at the receptacle-connection point eliminates even this sub-standard C-B protection.
 
Reply

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


Thread Tools
Search this Thread
Display Modes
'