Switchgear Maintenance Guide.
- Grupo Edmar
- Oct 10
- 4 min read
October 10, 2025 - Switchgear Maintenance Guide.
Switchgear Maintenance Guide.
Switchgear is a fundamental component of any electrical system, whether industrial, commercial, or power generation. Its function is simple but critical: to isolate circuits and ensure safety during maintenance work or maneuvers on the electrical grid.
Proper maintenance not only prevents unforeseen failures, but also protects expensive equipment such as transformers , switches, and control panels. In other words, taking care of switchgears is taking care of the entire electrical system.
What is an Switchgear and Why is it so Important?
A switchgear is a mechanical device that allows an electrical circuit to be opened or closed under no-load conditions . Unlike a switch, it is not designed to interrupt service current, but rather to visibly isolate a portion of the system.
Its main function is to ensure the safety of operators and allow other equipment (such as transformers or medium-voltage cells) to be operated safely.
In medium and high voltage systems, switchgear also allow for the isolation of line sections, substation sections or transformers, helping to maintain the continuity of the electrical supply.
Types of Switchgears and their Applications.
There are different types of switchgear depending on the environment in which they operate and their function within the electrical system. The most common are:
a) Indoor switchgear
Installed in electrical panels or cells, generally in medium-voltage networks (3.3 kV to 36 kV). They are compact and safe, ideal for industrial environments or commercial buildings.
b) Outdoor switchgear
Designed to withstand extreme environmental conditions such as rain, dust, or solar radiation. They are used in overhead lines or power substations.
c) Single-pole and three-pole switchgear
Depending on the application, they can interrupt one, two, or three phases. Three-pole transformers are the most common in three-phase distribution networks.
d) Switchgears with integrated earthing
They allow residual energy to be discharged after a disconnection, offering an additional layer of safety for technicians.
Each type must be selected considering the nominal voltage, the level of insulation and the environmental conditions where it will operate.
Importance of Preventive Maintenance.
Preventive maintenance aims to detect potential faults before they become major problems. In the case of disconnectors, this type of maintenance is essential, as mechanical wear and contamination can impair their insulating capacity.
The frequency of maintenance will depend on the operating environment:
In clean or indoor environments → an annual check is usually sufficient.
In dusty, humid or vibrating environments → it is recommended every six months.
In coastal or high salinity areas → a quarterly inspection is suggested.
Preventive maintenance reduces long-term costs, improves system reliability, and prevents service interruptions.
Basic Procedure for the Maintenance of Switchgear.
Efficient maintenance must be carried out following a clear and safe protocol. A general procedure is shown below:
Completely disconnect the circuit and confirm the absence of voltage.
Block and mark the work area to prevent accidental maneuvers.
Clean metal contacts with dry cloths or dielectric products.
Lubricate shafts and drive mechanisms with approved dielectric grease.
Check the alignment of blades and moving contacts.
Inspect the insulation : look for cracks, moisture or traces of partial discharge.
Check the tightness of bolts and electrical connections.
Test mechanical operation (manual or motorized) several times before re-energizing the system.
Practical Example: In a 115kV overhead line disconnector, proper maintenance can extend its useful life from 15 to more than 25 years, provided that it is cleaned and lubricated periodically.
Indicators of Wear or Failure in a Switchgear.
There are clear signs that a switchgear needs immediate maintenance or replacement. Some examples include:
Difficulty or stiffness when operating the mechanism.
Appearance of sparks, arcs or electrical noise during operation.
Loss of alignment between moving and fixed blades.
Dark coloration or burns on contacts.
Smell of ozone or burning material near the equipment.
Evidence of partial discharges or current leaks.
Detecting these symptoms early can prevent prolonged outages and damage to transformers, switches, or power cables.
Corrective Maintenance and Parts Replacement.
When a switchgear shows visible damage or advanced wear, corrective maintenance may be required. This involves a thorough inspection of mechanical and electrical components , and even the replacement of parts such as:
Main blades or contacts
Ceramic or resin insulators
Springs, axles or transmission arms
Drive motors
It is essential to use spare parts compatible with the manufacturer's original specifications and verify the recommended tightening torques. In cases where the switchgear has outlived its useful life or requires frequent repairs, it is recommended to consider replacing it entirely with a more modern and efficient model .
Maintenance as Part of Electrical Reliability.
Switchgear maintenance should be considered a strategic part of the electrical operation , not just a technical task. A well-maintained system ensures service continuity, prevents costly outages, and protects the electrical infrastructure.
In installations where power transformers, substations or medium voltage systems also operate, the correct condition of the disconnectors translates into greater safety and energy efficiency .
At Grupo Edmar , we promote the use of reliable electrical equipment that is an essential part of modern distribution systems, contributing to industrial, energy, and infrastructure projects nationwide.
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