User: Dsg319, Location: West Virginia
Asked on: Sunday, July 6, 2025 at 10:19 am EDT
Answered on: Sunday, July 6, 2025 at 10:19 am EDT
Question: How do these circuits even work? Cross neutrals somewhere out in the house?Standard 40ckt service panel (pre emergency disconnect era)Sometime along the line someone added an additional neutral bar and from what I can tell there is bonding screw nor a wire type bonding jumper so is no way physically attached to the service neutral in the panel. But obviously I still read continuity and circuits still work off this neutral bar.I come across this while just adding a 50amp gfci breaker for a camper.My question is how do these circuits even work? Just in series through the loads throughout the house that have the neutral that are on the original bonded neutral bar.And possibly mis matched crossed neutrals somewhere in device box or j box?Either way I’m going to install a wire typer bonding jumper back to the original neutral bar that is bonded to the panel.
You've uncovered a classic, and potentially dangerous, wiring problem. Here's a breakdown of what's likely happening and why it's problematic
Understanding the Problem: Bootlegged Neutral and Shared Neutrals
Bootlegged Neutral
This is where a neutral is connected to a grounding conductor (equipment ground) to create a return path for current. This is dangerous because the equipment ground is not designed to carry normal circuit current.
Shared Neutral
This is where two or more circuits share the same neutral conductor. This can be done properly under specific conditions (multi-wire branch circuits) to save on wiring but must be done carefully to avoid overloading the neutral.
Unbonded Neutral Bar
Your added neutral bar must be bonded to the main service neutral. If it's not, it is not a safe neutral point. The main neutral bar is the only place that's directly connected to the utility neutral, and therefore the only place where a neutral connection provides a low-impedance return path back to the source.
How Your Circuits are (Likely) Working - The Dangerous Path1. Improper Neutral Connection
Since your added neutral bar isn't bonded, the only way circuits connected to it can work is if they are finding a return path through one (or a combination) of these dangerous means:
Grounding conductors (the most dangerous): This is the most likely scenario. The circuits on your added neutral bar are finding a return path through the equipment grounding conductors, back to the panel, and then relying on a bootlegged neutral to complete the path back to the source. This means that under normal operation, current is flowing on the equipment ground. Shared neutral with another circuit
You could have circuits on the original neutral bar that share a neutral at some point in the house (intentional or unintentional).
Other unknown connections: It's possible that there are other unintentional connections between the added neutral bar and the main neutral somewhere in the house.2. Voltage Drop and Ground Faults
This situation creates several problems:
Elevated Voltage on Equipment Grounds
Any current flowing through the grounding conductors will cause a voltage drop along the wire. This means that the metal enclosures of your appliances and equipment are no longer at true ground potential. You could get a shock if you touch a faulty appliance and a grounded object.
Overloaded Neutrals
Shared neutrals (intentional or not) can become overloaded, leading to overheating, insulation damage, and fire hazards.
GFCI Issues
GFCIs work by detecting an imbalance between the current flowing through the hot and neutral conductors. If the neutral current is returning through a path other than the neutral wire, the GFCI will trip. This is why your new GFCI breaker might be tripping or not working as expected.
Inaccurate Voltage Readings
You may get incorrect voltage readings at outlets and lights.
Why the Bonding Jumper is Critical
A properly installed bonding jumper between your added neutral bar and the main service neutral bar will: Establish a Safe Return Path
Provide a direct, low-impedance path for neutral current back to the source.
Equalize Potential
Ensure that the added neutral bar is at the same potential as the service neutral, preventing voltage differences that can cause shocks.
Enable GFCI Protection
Allow GFCIs to function correctly by ensuring that the neutral current flows only through the intended path.
Immediate Actions and Troubleshooting1. Safety First
This is a serious safety hazard. Proceed with extreme caution. If you are not completely comfortable working with electrical systems, stop and call a licensed electrician.2.
Install the Bonding Jumper
This is your immediate priority. Connect a wire-type bonding jumper (sized appropriately for the service) between the added neutral bar and the main service neutral bar.3.
Verify Voltage
After installing the bonding jumper, check the voltage between the added neutral bar and a known good ground (like the metal enclosure of the panel, properly grounded). It should be very close to zero volts.4.
Trace Circuits
Once the immediate safety issue is addressed, systematically trace the circuits connected to the added neutral bar. Identify where they originate and where they run. Look for any evidence of shared neutrals or connections to grounding conductors.5.
Inspect Junction Boxes
Open all junction boxes along the affected circuits and carefully inspect the wiring for any signs of damage, loose connections, or improper wiring practices.6.
Professional Help
Given the complexity of the problem, I strongly recommend consulting with a licensed electrician. They can perform a comprehensive inspection of your wiring and identify any hidden issues. They can also correct any wiring errors to ensure your electrical system is safe and code-compliant.
Important Considerations NEC Compliance
Electrical work must comply with the National Electrical Code (NEC) and any local codes.
Grounding and Bonding
Understanding the principles of grounding and bonding is essential for safe and effective electrical work.
Testing
Use appropriate testing equipment, such as a multimeter, to verify voltage levels and continuity.
In summary, your circuits are likely working in a dangerous and potentially fatal way. Install the bonding jumper immediately and then systematically troubleshoot the wiring to identify and correct any improper connections. Flag for review