The Decisive Impact of Insulated Wire Construction Techniques and Insulation Testing Methods on the Quality of Concealed Works

The quality and service life of electrical installation projects are directly affected by the construction techniques used for insulated wires, making it a crucial aspect of concealed works acceptance. Before laying wires, a visual inspection should be conducted to ensure the insulation layer is undamaged, the conductor is free of oxidation, and the specifications meet design requirements. Specialized tools should be used for wire cutting to ensure clean cuts and avoid damaging the conductor. When laying wires in conduits, a wire puller or lubricant should be used to reduce friction between the wire and the conduit wall, preventing abrasion of the insulation layer. When multiple wires are laid in the same conduit, different circuits should be separated according to regulations to prevent mutual interference. Wire joints should be fabricated according to specifications, using crimping or welding methods to ensure good contact, and insulation restoration should reliably overlap with the original insulation layer. During the laying process, the wires must not be twisted, coiled, or have damaged insulation; each step requires strict quality control.

Insulation testing of insulated wires is a critical step in verifying construction quality and should be conducted after laying and before wiring. Insulation resistance testing is performed using a megohmmeter. The appropriate test voltage is selected based on the rated voltage of the wire; generally, a 500V megohmmeter is used for 500V wires, and a 1000V megohmmeter is used for 1000V wires. During testing, the wire should be disconnected from the equipment, and the phase-to-phase insulation and phase-to-ground insulation should be tested. The insulation resistance value should meet the specifications. For important lines, a withstand voltage test should also be performed, maintaining the specified voltage for a certain period to check for breakdown. Problems found during insulation testing should be promptly investigated and addressed, such as insulation layer damage, moisture absorption, or poor joints. After repair, the test should be repeated until it passes.

The acceptance of concealed works for insulated wires is the final confirmation of construction quality and requires the establishment of complete records. Acceptance content includes verifying the wire specifications and model, confirming the laying path, recording insulation test data, and marking joint locations. For concealed wiring, acceptance should be conducted before sealing the walls and floors, and photographic evidence should be preserved for future maintenance and tracing of the wiring route. Acceptance records should be compiled and archived as part of the project completion documentation. After the project is handed over for use, the construction unit should provide the user with basic information on the electrical wiring, including wiring routes, circuit distribution, and protection configuration, to facilitate daily use and maintenance. Through standardized construction techniques, rigorous insulation testing, and thorough acceptance of concealed works, the safe and reliable operation of the insulated wiring system can be ensured throughout the building's service life.