What Is a Bootleg Ground?
A bootleg ground is an improper connection between a receptacle's neutral terminal and equipment-grounding terminal somewhere downstream of the service disconnect. It is most often found in older wiring where a grounding conductor was never installed and someone tried to make a three-prong receptacle appear grounded.
The jumper can fool some simple three-light receptacle testers because neutral and equipment ground are normally close to the same voltage. What the jumper does not provide is the proper, dedicated equipment-grounding path the electrical system is supposed to have.
Why Is a Bootleg Ground Dangerous?
- Metal parts can carry normal neutral current: Downstream neutral-to-ground connections can put objectionable current on equipment-grounding conductors, metal boxes, raceways, and other bonded parts.
- An upstream neutral failure can create a shock hazard: If the neutral opens while equipment is connected, bonded metal parts may rise to a dangerous voltage.
- It can hide the real wiring condition: A basic receptacle tester may report a grounded outlet even though the cable has no equipment-grounding conductor.
- It is not a code-compliant substitute for grounding: Neutral and equipment ground are intentionally bonded at the service or other permitted source location, not arbitrarily at downstream receptacles.
What About GFCI Protection?
A GFCI does not need an equipment-grounding conductor in order to detect current imbalance and provide personnel protection. In some situations, properly installed and labeled GFCI protection is a code-permitted way to replace an older ungrounded receptacle. That is very different from installing a neutral-to-ground jumper to make the receptacle look grounded.
How Is a Bootleg Ground Identified and Corrected?
A simple plug-in tester cannot reliably prove that a receptacle has a legitimate equipment ground. An electrician can de-energize the circuit, inspect the wiring, trace the grounding path, and determine whether the correct repair is to restore an equipment-grounding conductor, replace wiring, or use another code-permitted method for an ungrounded receptacle.
If a home inspection or tester raises a grounding concern, the right goal is not to make the tester lights look correct. The goal is to verify the actual fault-current path and repair the wiring accordingly.
Related Electrical Issues
See also open electrical splices and breakers that keep tripping.