If you work in industrial power distribution—whether you’re a plant manager, maintenance supervisor, or electrical engineer—you already know that high-voltage (HV) metal-clad switchgear cabinets are the backbone of reliable, safe electricity delivery to heavy machinery, manufacturing lines, and entire facility operations. But what happens when these cabinets reach the end of their service life, or when you need to replace an outdated unit to accommodate a system upgrade? Decommissioning HV metal-clad switchgear isn’t just flipping a switch and pulling it out. It’s a highly regulated, multi-step process that demands precision, specialized training, and strict adherence to electrical safety standards to protect workers, the facility, and the environment. As a supplier of HV metal-clad switchgear cabinets with over 15 years in this space, I’ve walked through dozens of decommissioning projects with our clients, and I’ve seen firsthand how skipping even one small step can lead to costly delays, safety risks, or compliance issues. Let me break down the proven, industry-standard decommissioning procedures we recommend every client follow to do this job right. HV Metal-Clad Switchgear Cabinet
The first, and most non-negotiable, step in any HV switchgear decommission is planning and preliminary assessment. You can’t show up with a wrench and start disassembling a unit that’s carrying 13.8kV or 34.5kV of power—one wrong move can cause an arc flash, which is one of the deadliest hazards in electrical work. Before any physical work begins, our team works with clients to pull the original equipment’s design documents, as-built schematics, load flow diagrams, and maintenance history. This tells us critical details: how the cabinet is tied into the main bus, which feeders serve which parts of the facility, and if there are any backup systems or critical loads that need temporary power during decommissioning. We also conduct a full walkthrough of the switchgear room, noting access points, ventilation, nearby flammable materials, and the location of emergency shutdown (ESD) buttons. For example, last year we worked with a food processing plant that was decommissioning a 15kV switchgear cabinet serving their production line; their schematics showed a hidden feeder to a backup refrigeration compressor, so we worked with their operations team to reroute that load to a temporary portable generator before we touched the primary unit. Without that planning, they would have risked spoiling $200,000 worth of frozen product during the process.
Next comes lockout/tagout (LOTO) and voltage verification—this is the absolute foundation of electrical safety, and it’s not optional. OSHA, NFPA 70E, and the International Electrical Testing Association (NETA) all mandate strict LOTO procedures for working on energized electrical equipment, and HV switchgear is no exception. The process starts with shutting down all breakers in the target cabinet—main breaker, feeder breakers, and any grounding disconnects. Every worker involved in the project applies their own personal lockout/tag to each energy-isolating device, so no one can re-energize the cabinet without removing every lock. We also recommend bringing in a qualified electrical testing technician to perform multiple voltage verifications at multiple points: first at the main busbar, then at each feeder terminal, then at the grounding lug. It’s not enough to just use a standard multimeter; HV units require a high-voltage detector rated for the specific voltage class, and technicians must wait 10 minutes after shutdown for residual charge to dissipate before testing. I can’t tell you how many times I’ve heard of contractors assuming a breaker was fully de-energized only to find residual capacitance or trapped charge, which can cause serious injury. This step is non-negotiable, no exceptions.
Once the cabinet is confirmed completely de-energized, the next step is internal preparation and isolation of components. HV metal-clad switchgear is designed with individual removable compartments—circuit breakers, current transformers, voltage transformers, bus sections, and control relays—all mounted on metal carriages that slide out for maintenance. Before disconnecting any wiring, we carefully remove these carriages to prevent accidental contact with live parts (even stray static charge can be a hazard at HV levels). Each component is labeled clearly with its original location and function—this saves so much time during disposal or reuse, especially if the client wants to repurpose functional parts for a new cabinet. We also isolate bus connections within the cabinet using temporary insulating barriers, so that if nearby energized busbars run parallel, there’s no risk of flashover. For example, when decommissioning a 34.5kV unit at a mining site in Wyoming last year, we used custom-sized insulating barriers to separate the old de-energized bus from the adjacent energized bus that served the mine’s crushing operation. That barrier prevented a costly arc flash that would have shut down production for weeks.
With the cabinet internally isolated, we move on to disconnecting external connections. This includes power cables, control wiring, grounding conductors, and any interconnections to adjacent switchgear. Each cable is tagged with its feeder number, voltage rating, and connected load, and we take photos of the wiring before removing it—this is crucial if the client is installing a new cabinet in the same space, as it eliminates guesswork during reinstallation. For HV power cables, we never just cut them and leave the ends exposed; we cap them with industrial-grade high-voltage cable ends immediately after disconnection, to prevent moisture ingress or accidental contact. Control wiring is handled with even more care, as it carries low-voltage signals that might still be connected to building automation systems or backup controls. We also test each disconnected cable with a continuity tester to confirm that it’s no longer connected to any live circuits before moving it away from the switchgear.
Once all external connections are removed, the cabinet is ready for physical removal from the switchgear room. HV metal-clad switchgear cabinets are heavy—most 15kV units weigh between 2,000 and 4,000 pounds, and larger 34.5kV units can top 8,000 pounds or more—so lifting requires specialized equipment, like a forklift with a load capacity rated for the cabinet’s weight, or a crane if the switchgear room has limited access. Before lifting, we secure the cabinet with heavy-duty straps that are attached to its designated lifting points (never to control panels or auxiliary parts, as those aren’t designed to support the weight). We also ensure the switchgear room’s doors and hallways are clear, with all obstacles removed, and that the path to the loading area is level and free of debris. During removal, we work with the client’s safety team to set up a perimeter around the area, so no unauthorized personnel are nearby while the cabinet is being moved. Last year, a client tried to move a cabinet without securing it properly; it shifted mid-lift, damaged a nearby wall, and took three extra days to repair, costing them tens of thousands in lost production. Taking the time to plan the lift pays off every time.
After the cabinet is removed from the facility, the next critical step is proper decontamination and component separation. HV switchgear cabinets often have residual oil in circuit breakers (especially older oil-filled units) or insulating dust from years of operation. This debris can be hazardous, so we never just load the cabinet straight into a truck without cleaning it. We use non-conductive cleaning solutions to wipe down all external surfaces, and we carefully drain any residual oil from the breakers into approved, sealed containers for recycling. Internally, we separate components by material: copper busbars, aluminum wiring, steel frames, and electrical components like circuit breakers, transformers, and relays. Functional components that can be reused are stored in climate-controlled, moisture-proof containers, while damaged or end-of-life parts are disposed of according to local, state, and federal environmental regulations. For example, old oil-filled circuit breakers cannot be thrown in regular landfill, as the oil is considered hazardous waste; we partner with licensed e-waste and hazardous material disposal companies to ensure all parts are handled and disposed of legally.
The final step in the decommissioning process is documentation and post-project review. We provide our clients with a full decommissioning report, which includes photos of each step, voltage test results, LOTO lock counts, component inventory, disposal receipts, and any safety incidents or near-misses (we always note those, so clients can improve future projects). We also work with the client’s engineering team to compare the decommissioned cabinet’s specifications with the new unit they’re installing, to ensure that the new switchgear integrates seamlessly with their existing power system. For example, if the client is upgrading from 15kV to 25kV, we’ll review the busway dimensions and cable sizes to confirm that the new unit fits in the same footprint, minimizing installation delays.
As a supplier of HV metal-clad switchgear cabinets, our goal isn’t just to sell you a new unit—it’s to support you through every stage, from installation to decommissioning. We know that switching out old switchgear is a big investment, and you need a partner that understands how to do it safely, efficiently, and in compliance with all regulations. If you’re planning a switchgear decommissioning project, or if you have questions about what steps work best for your specific facility, reach out to our team to discuss your needs. We’ll provide a customized plan, connect you with certified technicians, and make the entire process as smooth as possible for your operations.
Fixed Type Switchgear References
NFPA 70E: Standard for Electrical Safety in the Workplace
OSHA 29 CFR 1910.331-1910.335: Electrical Safety-Related Work Practices
NETA Standard for Electrical Testing and Maintenance
IEEE C37.20.2: Standard for Metal-Clad Switchgear
Zhejiang Dongyu Electric Co., Ltd.
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