Torque Test

What this test verifies

Torque testing verifies that bolted electrical connections are tightened according to the specified torque values.

Why it matters

Proper torque helps prevent overheating, loose connections, and long-term reliability issues.

Typical commissioning stage

Typical stage

Measurement method

• Instrument: calibrated torque wrench (adequate range).
• Apply torque to target value in correct direction; record and re-tighten if necessary.
• Use manufacturer table and consider temperature/terminal material.

Acceptance criteria

• Torque within ± manufacturer tolerance.
• Discrepancies → check threads/terminals, possible terminal replacement.

Commissioning notes

Torque verification is the mechanical counterpart to electrical verification. It ensures that joints and terminals are tightened to the specified value so that contact pressure remains sufficient and stable over time. In electrical systems, incorrect torque is a common root cause of overheating, nuisance failures, and progressive degradation, especially in distribution assemblies where load currents and thermal cycles are significant.

In commissioning workflows, torque checks are performed after assembly, before energization, and often before contact resistance measurements. The engineer follows manufacturer torque tables or project specifications for each terminal type, conductor size, and hardware arrangement. The measurement is not simply tight or loose. It is the application or verification of a target torque value using a calibrated torque wrench or torque screwdriver with the correct range and method.

Execution must be consistent. Different joint materials (copper, aluminum), plating, lubrication, and temperature can influence friction and clamp load. Incorrect torque can occur in both directions: under‑torque leads to loosening and high contact resistance; over‑torque can damage threads, deform lugs, crack insulators, or reduce long‑term reliability. Good commissioning records the specified torque, the verified/applied value, the location (test point), and any observations (e.g., damaged hardware, stripped threads, replaced lug).

What torque verification detects: installation non-conformance (incorrect tightening), workmanship variation across joints, damaged hardware, and procedures that were not followed during assembly. While torque does not directly measure electrical resistance, it is strongly correlated with joint integrity, especially when combined with contact resistance results. In many projects, torque verification is a required QA step before the system is released for energization.

How Statria improves the process: Statria structures torque verification per test point with clear nominal vs verified fields (where applicable), required evidence, and deterministic evaluation. This reduces ambiguity in handover: each joint has a documented torque outcome and traceability (who verified, when, with which certificate). Finalize produces a consistent report that aligns mechanical verification with the overall commissioning workflow.

FAQ

Why is torque verification important if a connection already passes continuity?

Continuity does not guarantee adequate contact pressure. A loose connection can be electrically continuous but develop high resistance, overheating, and failures under load.

Should torque acceptance follow a standard or manufacturer values?

In most cases the manufacturer torque table is the primary reference, supplemented by project specs and applicable installation standards.

What’s the difference between nominal and verification torque in reporting?

Nominal torque is the specified target; verification torque is the value applied/confirmed during commissioning to demonstrate compliance.