Ground detected by Extension cord?


Old 03-17-19, 11:08 PM
Thread Starter
Join Date: Mar 2019
Location: United States
Posts: 6
Received 1 Vote on 1 Post
Ground detected by Extension cord?


Being fairly new to home ownership and eager to fix things at home, I'm encountering the following situation at home:
1. A power strip with ground indicator light is plugged into the wall outlet. The ground indicator light is lighting up green
2. When I opened up the electrical box cover, only a 2 wire cable was run into the box and no ground cable was connected from box to receptacle.

Are the power strip ground tests reliable or am I missing something here?

Sponsored Links
Old 03-18-19, 01:27 AM
ray2047's Avatar
Join Date: Mar 2006
Location: USA
Posts: 33,583
Received 13 Votes on 11 Posts
only a 2 wire cable was run into the box and no ground cable
It would be ground wire not cable.Are you confusing wire with cable? Are you sure it is cable not conduit into the box? If metallic cable ground could be through the metallic sheath. If it is early non-metallic cable with ground ground could be fastened outside of the box*. First though you need to verify with a multimeter.

*Old early versions of NM with ground can be identified by looking for #16 bare wires in the breaker panel.
Old 03-18-19, 06:32 AM
Join Date: Mar 2010
Location: USA
Posts: 4,109
Received 81 Votes on 75 Posts
No it is not reliable. No plug in device that shows a light to indicate a good ground connection is reliable.

Various incorrect and inadequate connections in the home electrical system will also cause the "ground" light to come on. For example if someone tried to use the neutral of a 2 conductor cable to double as the ground connection (not proper) then the ground light will also come on.

Many older systems with metal sheathed flexible conduit will test "correct" for a ground connection but might not have a code compliant, and good and sufficient, ground connection. A 16 gauge ground wire (equipment grounding conductor) in a non-metallic sheathed cable will provide a good ground for some situations but is no longer code compliant. Ten, twelve, and fourteen gauge NM cables e.g. Romex, the most common for household branch circuits, need a built in ground wire of like gauge.

Last edited by AllanJ; 03-18-19 at 06:52 AM.
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
Ask a Question
Question Title:
Your question will be posted in: