Racking and switching operations on medium and high-voltage switchgear carry some of the highest arc flash incident energy figures of any routine electrical task, precisely because the equipment being operated is designed to interrupt substantial fault currents — and a failure during that interruption happens right where the operator is standing.

Why racking and switching carry elevated risk

Racking a circuit breaker in or out of its cubicle, and operating a switch under load, both involve mechanically moving contacts within or near energised equipment at exactly the moment mechanical or electrical faults are most likely to manifest. Historical incident data across the industry consistently shows these operations as a disproportionate source of arc flash events relative to how routine they are, which is why they typically carry their own elevated PPE category separate from simple visual inspection or testing tasks on the same equipment.

PPE for racking and switching specifically

The incident energy for racking and switching operations should be calculated for that specific operation, not assumed from a lower-risk task on the same cubicle, and PPE selected accordingly — this often means the highest category of clothing rated to EN 61482 used on a site, an arc-rated hood rather than a face shield alone, and insulating gloves to EN 60903 matched to the equipment’s operating voltage. Where the equipment design permits remote racking or switching, operating from outside the calculated arc flash boundary removes the exposure entirely and is preferable to relying on PPE alone.

Positioning and door orientation

Standing to the side of a switchgear cubicle door rather than directly in front of it, where the equipment design allows, reduces direct exposure to the arc plasma jet in the event of a failure during the operation. Cubicle doors and covers should be closed and secured where the operation permits it, since an open door removes a layer of containment the equipment was designed to provide.

Procedure and sequence discipline

Racking and switching sequences are typically manufacturer-specified and, for protection-critical equipment, interlocked to prevent operations in the wrong order or state. Bypassing an interlock to save time removes a control specifically designed to prevent operating equipment in a state where a fault is more likely, and should never be treated as a routine workaround regardless of how familiar the equipment is.

For how the PPE category for this task is determined, see arc flash risk assessment, and for the boundary distances involved, see arc flash boundaries.

Frequently asked questions