If the Grounding Electrode Conductor (GEC) is removed from the utility transformer, the voltage from the ungrounded conductor to the earth will become unpredictable and potentially dangerous. Here's why: Normal Operation (GEC Present)

The GEC connects the neutral point of the transformer winding to a grounding electrode (e.g., ground rod, water pipe). This creates a low-impedance path for fault current to flow back to the transformer in the event of a ground fault. This low impedance path causes a large current to flow, which quickly trips a circuit breaker or fuse, clearing the fault and preventing dangerous voltage buildup on grounded metal parts. The neutral is held near ground potential (ideally 0V), so the voltage from any ungrounded conductor to ground is essentially the normal phase-to-neutral voltage (e.g., 120V in a typical 120/240V system).

GEC Removed (Loss of Ground Reference)

Without the GEC, the neutral point of the transformer is no longer effectively tied to ground. Now, if a fault to ground occurs, there is no low impedance path to facilitate the high fault current needed to trip the overcurrent device. In the event of an insulation breakdown or a ground fault on an energized conductor, the voltage on grounded parts can rise significantly. The voltage from the ungrounded conductor to earth will also rise above the normal phase-to-neutral voltage. The exact voltage will depend on various factors, including:

Capacitive Coupling

There's always some capacitive coupling between conductors and ground. This can cause the neutral point to "float" to some voltage above ground, determined by the impedance of the load.

Inductive Coupling

The same is true for inductive coupling.

Leakage Current

Insulation is never perfect. Small leakage currents can flow between conductors and ground.

Fault Conditions

If there is a fault on one of the circuits served by the transformer, this would severely affect the voltage to ground of the ungrounded conductor.

Danger

This situation is extremely dangerous because:

Electric Shock Hazard

Anyone touching a grounded metal part could receive a severe or fatal electric shock. The voltage on the grounded parts could be significant and remain for an extended period since the overcurrent device does not trip.

Equipment Damage

Equipment connected to the system can be damaged by overvoltage.

Arcing and Fire Hazard

High voltage can cause arcing, leading to fires.

In summary

Removing the GEC creates a floating ground, making the voltage between the ungrounded conductor and earth unpredictable, uncontrolled, and extremely dangerous. It can rise to a value much higher than the normal line-to-neutral voltage. This situation eliminates the safety mechanisms designed to protect people and equipment from ground faults.

Never remove or disconnect the GEC from a utility transformer.Disclaimer: This information is for educational purposes only and should not be considered a substitute for professional electrical advice. Working with electrical systems can be dangerous. Always consult with a qualified electrician before performing any electrical work. Flag for review