The following is the standardized insulation testing process and operating points for waterproof cable laying:

1、 Preparation before testing

1. ‌Safe power-off and discharge‌

   • Cut off all power sources of the cable and hang and lock it. Use a discharge rod to discharge the conductor and metal sheath continuously for ≥ 2 minutes to eliminate residual charges.

   • Detect environmental humidity<80%, temperature should be within the range of 5-35 ℃, avoid rainy or high humidity periods
     .

2. ‌Equipment selection and calibration‌

   ‌Cable type‌	‌Megohmmeter voltage‌	‌Equipment Requirements‌
   Low voltage (≤ 1kV)	1000V	Open circuit test pointer to ∞, short circuit reset to zero
   High voltage (>1kV)	2500V/5000V	Select multi output instruments such as ETCR3500

2、 Test operation process

1. ‌Wiring specifications‌

   • Test the insulation between each core and other parallel grounded core wires in sequence (e.g. test four times for a four core cable)；

   • Shielding layer connected to G terminal to eliminate surface leakage current interference
     .

   • ‌single-core cableConnect the L end to the conductor and the E end to the metal sheath (connect to the grounding wire when there is no sheath)
     ；

   • ‌multi-core cable‌：

2. ‌Parameter Setting and Measurement‌

   • Shake the handle at a constant speed of 120 revolutions per minute and maintain a stable test voltage for 1 minute
     ；

   • Record the insulation resistance value (unit: M Ω) at 60 seconds, and synchronously record the value of the high-voltage cable for 15 seconds to calculate the absorption ratio (R60s/R15s)
     .