Engineering reference provided by the technical team at TransformerGrid.com.

Cable Compartment Pre-Energization Inspection Checklist

Technical Summary

Commissioning is the last opportunity to detect cable compartment defects before the equipment is energized. Once voltage is applied, a missed bend-radius violation, loose bushing connection, or unsealed conduit becomes a live fault — not a punch-list item. This checklist reflects the highest-frequency findings from field experience.

1. Electrical Integrity

Inspection pointWhat to checkCommon finding
Stress cone seatingFully engaged on the bushing, no gap, no tilting. Verify against termination manufacturer installation guide.Cone not fully seated; partial discharge risk at the bushing interface
Bushing terminal torqueVerify every bolted connection with a calibrated torque wrench against the connector manufacturer specification.Under-torqued (loose → heating → thermal runaway) or over-torqued (stripped threads)
Grounding connectionsAll ground conductors landed, labelled, and tight. Bonding jumper between compartment barrier and enclosure present and intact.Missing bonding jumper; ground path relies on incidental metal-to-metal contact

2. Mechanical Integrity

Inspection pointWhat to checkCommon finding
Cable support bracketsTight, aligned, and visibly carrying cable weight. No cable hanging from bushing terminal alone.Bracket loose, missing, or positioned too far from termination to be effective

3. Environmental Protection

Inspection pointWhat to checkCommon finding
Conduit sealsInstalled, compressed, no visible gaps. Expanding foam is not an acceptable permanent seal — use a removable waterproof compound.Missing or improperly sized seal; provides direct path for water and pests from the duct bank
Door gasket integrityContinuous around the full perimeter, not compressed flat, no cuts or tears.Gasket pinched or folded during door installation; leaves an unsealed gap

4. Documentation

Inspection pointWhat to checkCommon finding
As-built measurementsRecord actual torque values, bend radius measurements, and ground resistance readings on the checklist form.No recorded values — only checkmarks. If a termination fails later, there is no evidence it was correctly installed.

5. Operational Readiness

Inspection pointWhat to checkCommon finding
Compartment cleanlinessNo debris, tools, wire clippings, metal shavings, or standing water anywhere in the compartment. Sweep the entire compartment floor and check behind cables.Metal shavings from conduit cutting — potential short-circuit path between phases or to ground once energized

6. Post-Commissioning Documentation

Every inspection point should be initialled with the date and — where applicable — the measured value. This serves as warranty evidence (proving installation met manufacturer requirements at energization) and as an asset management baseline for future periodic inspections and trend analysis.

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