Okay, this situation is dangerous and requires immediate action. You're dealing with a potentially lethal voltage on grounding conductors, which is a serious safety hazard. Let's break down the situation and how to proceed

Understanding the Problem:
Hot Neutral

This means the neutral conductor is elevated to a significant voltage (117V in your case) above ground potential. This is not normal and indicates a fault condition.

Missing System Bonding Jumper (SBJ)

This is the root cause. The SBJ is required to connect the neutral conductor to the grounding system (typically the enclosure). Without it, the neutral current has no defined return path and can energize the grounding conductors. Think of it as giving electricity a preferred path and potential path where it is less hazardous.

Voltage Between EGC and Neutral

The 117V you're measuring confirms that the EGC (equipment grounding conductor) is carrying current and is therefore energized.

No SBJ at Transformer or Panel

This reinforces the fundamental problem. Neither the transformer nor the panel board has a designated neutral-to-ground connection.

Immediate Safety Precautions


Treat ALL Metal Enclosures as Energized

Until the problem is resolved, assume that any metal enclosure connected to the electrical system (panels, conduit, junction boxes, appliance chassis, etc.) could be carrying a dangerous voltage. Do not touch them without proper PPE and procedures.2.

Warning Signage

Post prominent warning signs indicating "Electrical Hazard - Elevated Ground Voltage - Do Not Touch" near the panel and transformer location.3.

De-energize if Possible

If safely possible, de-energize the transformer feeding the panel. If you can do so without creating a larger safety risk, this is the best immediate step.4.

Contact a Qualified Electrical Contractor IMMEDIATELY

This is not a DIY situation. You need a licensed and experienced electrician with the appropriate test equipment and expertise to diagnose and correct this fault.5.

Document Everything

Take detailed notes and pictures of your measurements, the equipment, and the absence of the SBJ. This will be helpful for the electrician.

Steps to Correct the Problem (Performed by a Qualified Electrician)


Verify No Load on System Ensure all loads on the panel are disconnected before installing SBJ. This is necessary to avoid large fault currents upon installing SBJ.2. Install System Bonding Jumper (SBJ) at the Transformer

This is the primary correction. The electrician will install a properly sized SBJ from the neutral conductor to the transformer enclosure. This may be the only location to install SBJ.

Sizing is Critical: The SBJ must be sized according to the applicable electrical code (NEC in the US) based on the size of the transformer's secondary conductors. Proper Connection: The connection must be made using approved methods and hardware, ensuring a low-impedance path.3.

Inspect and Correct EGC Connections

The electrician will need to carefully inspect the grounding system to ensure that all EGCs are properly connected back to the panel. This may involve tightening connections, replacing corroded components, or adding additional grounding electrodes if necessary.4.

Panel SBJ Inspection/Removal

After correcting the transformer SBJ, the electrician should inspect the panel to ensure there isn't an accidental SBJ already installed. In most cases, only one SBJ is permitted in a system, and it's typically located at the service entrance (which, in this case, is the transformer secondary). If there's an accidental SBJ at the panel, it needs to be removed.5.

Testing and Verification

After the SBJ is installed and the grounding system is verified, the electrician will use a low resistance ohmmeter to verify that there is now a low impedance path between the neutral and ground. They will also use a voltmeter to verify the voltage between Neutral and EGC is now within safe limits (close to 0V). They may also perform load tests to verify proper system operation.

Potential Issues After SBJ Installation

You're right to be concerned about what might happen when the SBJ is installed. Here's what could occur:

Breakers/Fuses Tripping

When the SBJ is installed, the return path is established, and now there is a defined path. If there's a pre-existing ground fault (e.g., damaged insulation on a wire contacting a metal enclosure), installing the SBJ will cause a large fault current to flow, tripping the corresponding breaker or blowing the fuse. This is a good thing! It's clearing a fault that was previously hidden.

Equipment Malfunction

If there's a ground fault in equipment, installing the SBJ may cause that equipment to malfunction or stop working as the fault current flows.

Neutral Current Issues

A properly installed SBJ may reveal issues with neutral current imbalances, especially if there are a lot of non-linear loads (electronics, LEDs, etc.). This can lead to nuisance tripping of breakers.

Sparking/Arcing

If there are loose connections or corroded wiring, the sudden flow of fault current could cause sparking or arcing, which is a fire hazard.

In summary



Do not attempt to fix this yourself.

Prioritize safety.

Contact a qualified electrician immediately.

Be prepared for potential problems after the SBJ is installed, as it may reveal hidden faults.This is a serious situation, and it's important to take the necessary precautions to ensure the safety of yourself and others. Good luck, and please let a qualified electrician handle this. Flag for review