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Missing Ground is a loss of continuity from any point on the grounding system at a facility to the grounding electrode system, or GES. Once a missing ground is identified, it should be permanently reconnected through construction similar or superior to the original installation. This section addresses some options if you must temporarily deal with a missing ground.
Common events that interrupt bonding and grounding include these
Missing grounds can be corrected and re-connected through the ISBP, which is built for current flow and is well suited to adding grounds. NEC permits grounding through the GEC and the grounding electrode system, so using an ISBP bonded to the GEC should not be a problem. Make all connections to the corresponding sponsoring module of the ISBP when restoring grounds for a system.
When one cannot rebuild or re-wire the existing power outlets missing ground, then one can construct a device to work around the problem. It would be good pre-planning to build this device in advance for ready use when needed.
The device, plus one tested and proven 3-wire extension cord, can restore a missing ground at moment's notice.
Construct two boxes (such as 4 X 4 size) fastened together. In each box, place a 120-V power receptacle isolated from the other box with only a shared bonding jumper crossing the boxes. Wire each 120-V outlet to its own plug cord. Then plug one into the system missing ground. The next outlet must be plugged into a well-grounded outlet.
It would be ideal to fill the boxes with the maximum number of bonding jumpers by filling all available bonding points between the boxes, to increase the ampacity of the restored ground connection. As a bonus to the restored ground, you have two extra 120-V outlets available to use.
Another inexpensive technique would be to get two new plastic three-prong plugs and string one ground wire between them, while isolating the other two prongs from ground and from each other. It is cheap, and will work, but the quality of the ground is limited to the ampacity of your chosen wire and the connection at each outlet.
Missing Ground is a loss of continuity to the GES from any point on a facility grounding system.
Common and frequent events can interrupt bonds and grounding, causing the problem of missing ground.
Missing ground is an unacceptable hazard. Correct missing ground immediately upon detection.
There are temporary work arounds if a permanent solution cannot be used first. An ISBP connected directly to the GEC is the preferred connection point for restoring a missing ground.
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