In industrial plant management, there are obvious electrical faults that instantly stop a machine, such as a short circuit. However, there is a much more subtle, progressive, and destructive anomaly that often goes unnoticed until the damage is catastrophic: the ground fault. This phenomenon not only puts the physical safety of operators at risk, but is also directly responsible for nuisance tripping of protections, data loss in control systems, and a silent degradation of equipment insulation. At EREMU, we analyze this challenge from the perspective of magnetic engineering to offer solutions that cut the problem at its root.
What exactly is a ground fault and why does it occur?
A ground fault is an unwanted deviation of electrical current outside the active conductors of the circuit. Under ideal conditions, all the current entering through the phases of a system must return through the neutral or the remaining phases. However, when the insulation of a cable, motor, or transformer degrades, a fraction of that current (called residual current) seeks an alternative path to the ground through metal enclosures, building structures, or the conductive ground itself.
The most common causes in industrial environments include:
-
Thermal aging: High operating temperatures dry out and crack the insulating varnishes of motors and transformers.
-
Moisture and contamination: Conductive dust, oils, or water condensation create superficial paths that facilitate current leakage.
-
Mechanical stresses: Continuous vibrations in machinery that rub cables against the edges of terminal boxes until their protective jacket breaks.
The new scenario: Power electronics and high-frequency leakage
Traditionally, ground faults were associated with pure faults at grid frequency (50 or 60 Hz). However, the massive introduction of variable frequency drives (VFDs), solar inverters, and switched-mode power supplies has changed the rules of the game.
This equipment switches current at thousands of hertz (high frequency), generating capacitive currents that leak to ground through the natural stray capacitances between the windings and the metal enclosures. The result is a high-frequency ground fault that conventional residual current devices (RCDs, Type AC or A) cannot measure correctly, causing two critical scenarios: they either trip without a real fault existing (nuisance tripping), or they become “blinded” and fail to act in the event of a real danger of electrocution.
Consequences beyond safety
Although protecting human life is the absolute priority of any grounding system, an undetected ground fault has a severe impact on a company’s bottom line:
-
Galvanic corrosion: Currents circulating erratically through the metallic structures and pipes of the building accelerate their oxidation and mechanical degradation.
-
Electromagnetic noise: Leakage currents inject interference into the ground network, corrupting the communication signals of PLCs and precision sensors, which causes data reading errors and mysterious shutdowns on assembly lines.
-
Chronic energy losses: A constant leakage is energy that is billed but dissipated as heat in the subsoil, reducing the global energy efficiency of the plant.
How to eradicate the problem? EREMU’s magnetic solution
When the plant design demands that a ground fault at a critical point (such as a data center or a continuous production line) must not stop the entire factory, the solution relies on galvanic isolation.
EREMU’s isolation transformers act as an impassable border for residual currents. By transferring energy exclusively magnetically through a silicon steel core, the secondary circuit is completely electrically disconnected from the main power grid.
-
Creation of a new earthing system: By installing our isolation transformer, you can create a local distribution system (for example, an IT system) where a first ground fault does not cause an immediate trip of the protections, allowing production to continue while monitoring systems alert the maintenance team to schedule the repair.
-
Integrated electrostatic shields: Between the primary and secondary of our transformers, we place copper shields connected to ground that capture and divert high-frequency leakage currents generated by modern electronics, preventing them from contaminating the rest of the installation.
Conclusion: Controlling the flow to protect the business
A ground fault should not be considered a simple inevitable mishap of electricity, but rather a symptom of wear and tear or a consequence of a poorly filtered network. Having an infrastructure that combines a correct diagnosis with high-quality magnetic isolation equipment is the only effective strategy to ensure that current flows strictly where it should.
At EREMU, we provide you with our experience in designing transformers and reactors that confine energy to its proper channels, shielding your processes against interference and guaranteeing maximum operational safety.
Are you suffering from nuisance tripping or voltage drops due to leakage currents?
Do not allow an invisible fault to compromise your company’s productivity. At EREMU, we design custom isolation transformers adapted to the load and frequency conditions of your plant to neutralize the effects of ground faults.
Consult EREMU engineers today and protect your infrastructure here
