How a Switchgear Works: Step by Step.
- Grupo Edmar
- Aug 25
- 4 min read
August 25, 2025 - Operation of the Switchgear.
How a Switchgears Works: Step by Step.
An switchgear is a device designed to physically isolate a part of an electrical installation, leaving it completely free of voltage and safe to handle. Unlike a circuit breaker, its primary function is not to interrupt load currents, but rather to ensure a visible disconnection point .
Its importance lies in the fact that it allows operators and technicians to work with the confidence that no power is circulating in that section of the system. This is essential in industrial plants, medium- and high-voltage substations , and even in generation projects such as solar and wind farms.
Step 1: Pre-Check.
Before operating a switchgear, a series of checks must be carried out to avoid risks:
Confirm there is no load : Switchgear are not designed to interrupt working current. Attempting to open them with a load would result in dangerous arcing. Therefore, circuit breakers are used first to disconnect the load.
Status of protective equipment : Fuses, protection relays and automatic systems must be in correct operation.
Visual inspection : Check that the switchgear mechanism is not damaged, corroded or has loose parts.
Personal safety equipment (PPE) : Dielectric gloves, face shield, and in some cases portable voltage detectors.
Example: In a substation, the operator first opens the circuit breaker feeding the line. Only after verifying the absence of voltage can he proceed with the switchgear.
Part 2: Opening of the Circuit.
Once safety is confirmed, the switchgear is opened. This can be done in two ways:
Manual : The operator operates a lever or crank that moves the switchgear blades. This movement physically separates the metal contacts.
Motorized : In modern installations, especially in medium and high voltage installations, the switchgear can be opened by an electric motor, even from a remote control center. This not only increases safety but also allows for rapid response in the event of an emergency.
It is important to note that the movement must be quick and firm , to avoid residual electric arcs during opening.
Step 3: Visible Isolation.
One of the greatest benefits of a disconnect switch is that it offers visible isolation . The operator can verify with his own eyes that the contacts are completely separated, eliminating any doubt about whether the line is energized.
In knife-edge systems, this isolation is very evident: the metal parts are separated and visible. In encapsulated models (such as those using SF6 gas ), mechanical indicators are included to show the status of the switchgear.
Example: In a photovoltaic plant, a technician can open the switchgear and see how the blades are suspended in the air, ensuring that there is no electrical continuity to the inverter.
Step 4: Grounding (Optional but highly recommended).
In critical installations, the switchgear usually incorporates a grounding blade . Once the circuit is open, the operator can lower this blade and connect the insulated section directly to ground.
This serves two functions:
Discharge any residual or induced voltage.
It ensures that even if there is a system error, there will be no risk of accidental re-energization.
Example: On high-voltage transmission lines, a grounding switch is required to protect workers performing maintenance on towers or cables.
Step 5: Work in a Safe Zone.
With the switchgear open and grounding applied (if applicable), personnel can work on the facility. This ensures that the equipment, transformers, or lines are free of energy.
Some benefits of this step:
Possibility of performing preventive and corrective maintenance without interrupting the entire installation.
Electrical risk reduction.
Greater confidence for technical staff, knowing that the insulation is visible and reliable.
Example: In a wind farm, only the switchgear of a specific wind turbine can be opened for maintenance, without having to shut down the entire farm.
Step 6: Closing the Circuit (Restoration).
When the job is complete, the connection is reestablished. This process includes:
Remove the grounding.
Close the switchgear manually or motorically.
Check that the contacts are correctly coupled.
Reactivate the load using the corresponding circuit breaker.
It's important to do this in an orderly manner to avoid power surges or faults. In installations with a built-in fuse, this switchgear automatically protects against overload or short circuit.
Step 7: Post-Maneuver Verification and Documentation.
The last step is to make sure everything is working properly:
Check that the switchgear closes without mechanical resistance.
Check for any strange noises, sparks, or vibrations.
Check that the cabinet is properly closed and sealed, preventing the entry of dust or moisture.
Document the maneuver with the date, time, and name of the person responsible.
In companies with strict safety protocols, this record is mandatory, as it is part of the operation and maintenance audits. The operation of a switchgear is not simply "opening or closing a switch": it is a process with well-defined steps that guarantee safety and operational continuity.
At Grupo Edmar, we know that choosing a reliable switchgear is key to protecting both the facility and personnel. That's why we offer technical advice and equipment.
High quality products that meet international standards and the needs of each project.
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