Supplied B1 Module 07A textbook: PDF pages 175–204.
Continuity, insulation and bonding
Continuity verifies an intended conductive path. Insulation testing checks unwanted leakage between conductors or to structure using a specified test voltage. Bonding testing checks a low-resistance connection needed for electrical return, static discharge or electromagnetic protection. These are different tests and their limits are not interchangeable. Isolate equipment as directed before applying an insulation test, then discharge the circuit safely if required. A wire may show continuity yet have damaged insulation; a bonded joint can look secure yet have excessive resistance.
Which test checks unwanted leakage through insulation? Insulation resistance testing.
Wire identification and condition
Identify the wire by its complete specification, size and markings. Assess chafing, damaged insulation, overheating, corrosion, broken strands and contamination using the defined acceptance criteria. A larger-looking wire is not necessarily an approved replacement: current capacity, temperature rating, insulation properties and installation environment matter. Check bends, clamp positions and areas next to structure, moving equipment and fluid lines. A clean external surface does not prove that hidden strands or conductor terminations are intact.
What establishes whether a damaged wire may remain in service? The applicable inspection and damage limits.
Crimp tools and joint testing
Crimping creates a controlled mechanical and electrical connection by deforming a terminal around a prepared conductor. Match wire size, terminal, die, locator and tool setting. Strip the specified length without nicking strands and insert the conductor fully. Inspect the finished crimp for correct positioning, retained strands and insulation support. Pull tests or sample process checks are performed when required. A ratchet's completed cycle proves only that the tool completed a cycle, not that the wrong terminal or die became acceptable.
What must match for a satisfactory crimp? Wire, terminal, die and tool setup.
Connector contact insertion and removal
Identify the connector, contact and cavity before work. Use the correct insertion or extraction tool, particularly for rear-release and front-release contacts. Release the retention mechanism rather than pulling on the wire. Examine seals, contact condition and cavity damage; check that the contact locks into place as specified. Protect disconnected connectors from moisture, dirt and accidental shorting. Reconnect with correct alignment and locking. A backed-out contact can produce intermittent faults that disappear when the connector is moved.
Why is the correct contact-removal tool necessary? It releases retention without damaging the contact or cavity.
Coaxial cables and shields
Coaxial cable places a centre conductor inside dielectric and an outer conductor or shield. Its dimensions and termination determine characteristic impedance and signal performance. Excessive bending, crushing or a poor connector can disturb impedance even if DC continuity is satisfactory. Maintain specified bend radius and routing, avoid sharp clamp pressure and use the approved termination method. Shield continuity and bonding must follow the installation design; do not universally earth every shield at both ends. Inspect for moisture entry and damaged jackets.
Why may a coaxial cable pass continuity but fail a signal test? Its impedance or shielding may be disturbed.
Routing, protection and cleanliness
Support looms with the specified clamps and spacing, allowing for movement without excessive slack. Prevent contact with sharp edges, moving controls, hot zones and fluid sources. Use approved sleeving and heat-shrink material; do not use a sleeve to hide unacceptable damage. Maintain separation and shielding requirements. Clean as you go during nearby drilling or sanding, protect open equipment and remove debris without driving it into connectors. Wiring maintenance includes surrounding supports and contamination sources, not only the conductor itself.
Why is wiring cleaned during nearby metalworking? Conductive debris can damage insulation or create shorts.
Apply the knowledge
Work through these examples before starting the quiz. Explain why the other choices would not meet the requirement.
A crimp passes a tug check but was made with an incorrect die. What is appropriate?
Treat it as nonconforming and apply the approved correction — Tool and terminal compatibility are part of the qualified process.
A wire has chafed insulation but still shows continuity. What does this mean?
Continuity does not establish insulation serviceability — Conductive path and insulating condition require different assessments.
A shield connection is corroded. Which effect is plausible?
Degraded bonding and electromagnetic protection — Shield performance depends on correct termination and sound bonding.
Before an insulation test on an electronic circuit, what is essential?
Disconnect or protect equipment as the approved task directs — Insulation test voltages can damage sensitive electronics.