This is a serious electrical safety concern and needs to be addressed immediately. Here's a breakdown of potential causes and how to troubleshoot

Understanding the Problem

The fact that the entire can of the retrofit fixture is energized with 120V when the ground is disconnected indicates a significant fault. This means a conductive path has developed between the hot conductors and the metal housing of the fixture. The grounding system is acting as the only path for this fault current, making the ground wire a critical safety device. Removing it exposes anyone touching the fixture to a potentially lethal shock.

Possible Causes (in order of likelihood)

1.

Wiring Fault Inside the Retrofit Fixture



Damaged Insulation

A wire inside the fixture could have damaged insulation, allowing a hot conductor to touch the metal housing. This is especially likely during manufacturing or installation (pinched wires, sharp edges).

Loose Connections

A loose connection on the hot side could be arcing to the metal housing. Vibration during operation or shipping can cause this.

Manufacturing Defect

The LED driver itself could be faulty and leaking voltage to the housing. Cheaper drivers are more prone to this. This is also more likely if multiple fixtures are exhibiting the same issue.

Incorrect Wiring

Someone at the factory may have wired something incorrectly within the fixture.2.

Internal Short in the LED Driver(s)

LED drivers often use capacitors internally to filter and smooth the DC output. A failure of one of these capacitors could cause a leakage of AC voltage to the driver's chassis, which is often bonded to the fixture housing. This is a common failure mode for aging or poor-quality drivers.3.

Neutral-Ground Bond Issue (Less Likely, but Possible)

While your system is two legs of a 480V Wye, there's still a neutral somewhere in the system (at the service entrance or transformer). If there's an accidental connection between the neutral and ground downstream of that point, it could potentially cause some odd voltage readings. This is less likely with a simple 2-leg 480V setup but needs to be considered.

Troubleshooting Steps (SAFETY FIRST!)



WARNING: Working with electricity is dangerous. If you are not a qualified electrician, DO NOT attempt these steps. Hire a professional.1. De-energize ALL circuits



ABSOLUTELY ESSENTIAL. Turn off the breakers feeding all of the affected parking lot poles. Verify that power is OFF at the pole and the fixture using a reliable voltmeter and a non-contact voltage tester.2. Visual Inspection (Before ANYTHING Else)



Wiring Inside Fixture

Open up the fixture (refer to the manufacturer's instructions) and carefully examine the wiring. Look for: Pinched wires Wires with cracked or worn insulation Loose connections (both on the hot, neutral, and ground wires) Wires that are touching the metal housing Evidence of arcing (burn marks)

LED Drivers

Visually inspect the drivers. Look for: Burn marks Bulging or leaking capacitors Any signs of physical damage3.

Resistance Testing (with power OFF)



Resistance to Ground

Use a multimeter set to measure resistance (Ohms). With the power OFF and the fixture disconnected, measure the resistance between each hot wire and the metal housing of the fixture. You should see infinite resistance (or a very, very high number, like megaohms). If you see a low resistance (anything less than several megaohms), that confirms a short to the housing.

Isolate the Problem

If you find a low resistance, disconnect the wires to the LED driver. Then, test resistance between the LED driver input and its case. Also test the resistance between the fixture wiring leading to the driver and the fixture housing. This will help you determine if the fault lies in the driver itself or in the wiring within the fixture.4.

Driver Testing (with power OFF and disconnected)



Driver Isolation

Disconnect the LED drivers completely from the fixture and the incoming power. Use a multimeter to check the resistance between the input terminals (hot and neutral) of the driver and its metal case. There should be extremely high (ideally infinite) resistance. A low resistance reading indicates a fault within the driver.5.

Re-create the Problem (Carefully and Briefly)

If you haven't found a clear fault yet, and only after doing steps 1-4, you can cautiously try to re-create the problem on one fixture to help isolate the issue.

IMPORTANT

Wear proper PPE (insulated gloves, safety glasses). Connect the fixture to the power source (with the breaker off). Turn on the breaker.

Carefully use a non-contact voltage tester to check the fixture housing for voltage. If the housing is energized, IMMEDIATELY turn off the breaker. Then, using a voltmeter, carefully measure the voltage between the fixture housing and a known good ground. This will confirm the 120V reading you observed earlier.6. Check the System Grounding

Ensure the ground wire is properly connected to the pole. Verify the grounding electrode conductor (GEC) at the service entrance or transformer is intact and properly connected to a grounding electrode (ground rod, water pipe, etc.).

Corrective Actions



Replace Faulty Fixtures

If you find a short in the wiring or a faulty driver, the fixture must be repaired or (preferably) replaced. Don't try to "patch" a shorted wire.

Review Installation Procedures

Make sure the installation was done correctly, and that no wires were pinched or damaged during installation.

Contact the Manufacturer

Notify the manufacturer of the retrofit fixtures about this problem. They may have encountered similar issues and have a solution or recall in place. Provide them with the model number and any batch numbers from the fixtures.

Consider Higher-Quality Drivers

If the problem is with the drivers, consider replacing them with higher-quality, more reliable drivers from a reputable manufacturer.

Key Takeaways



Safety is paramount. This is a serious electrical hazard that must be addressed immediately. Don't ignore the problem. Grounding is a safety system. If it's carrying current, something is wrong. Thorough troubleshooting is essential. Identify the root cause of the problem before attempting any repairs.* Use a qualified electrician. Electrical work should only be performed by qualified professionals.

In summary, this is almost certainly a manufacturing or wiring defect within the retrofit fixtures themselves. Thorough visual inspection and resistance testing should reveal the source of the fault. Do not operate these fixtures until the problem is resolved. Flag for review