faq

• Q

  What are the tensile strength and elongation requirements for cable sheaths?

  A

  Per IEC 60811-501, typical:

  - PVC sheath: tensile ≥12.5 MPa, elongation ≥150%

  - LSZH sheath: tensile ≥10 MPa, elongation ≥150%

  - Rubber sheath: tensile ≥10 MPa, elongation ≥250%

  After ageing (100°C, 7d), retention ≥80%. Specific values vary by product standard.

  Source: IEC 60811-501 & product standards.

• Q

  What is the difference between withstand voltage and breakdown voltage of a cable?

  A

  Withstand voltage: test voltage (2–2.5× rated) applied for 1 min, must not break down. Routine test.
  Breakdown voltage: critical voltage causing insulation failure, much higher, used for destructive sampling.
  Relationship: breakdown ≥ withstand × factor (usually 1.2–1.5). Standards: IEC 60227-2 (withstand), IEC 60243 (dielectric breakdown).

• Q

  What is the international standard for cable color coding (phase colors)?

  A

  Region	Phases L1/L2/L3	Neutral N	PE
  EU (IEC 60446)	brown / black / grey	blue	yellow/green
  US (NFPA 70)	black/red/blue (120/208) brown/orange/yellow (277/480)	white or grey	green or bare
  China (GB 50303)	yellow / green / red	blue	yellow/green

  Yellow/green reserved for PE only.

• Q

  How to choose between fiber optic and copper cable in industrial environments?

  A

  Distance: fiber (km) >> copper (≤100m for Ethernet).

  EMI immunity: fiber immune; copper requires shielding.

  Cost: fiber material higher, connectors expensive; copper lower.

  Environmental: fiber sensitive to bend/tension; copper more robust.

  Fiber for long distance, high EMI, lightning risk; copper for short, mobile, cost-sensitive.

• Q

  What are the differences between coax types RG6, RG59, RG11?

  A

  Type	Impedance	Center cond (mm)	Attenuation (100m@100MHz)	Typical use
  RG59	75Ω	0.58	~11 dB	Short video, CCTV
  RG6	75Ω	1.02	~6.5 dB	Satellite, CATV, HD
  RG11	75Ω	1.63	~4 dB	Long runs, outdoor

  Per MIL-C-17 or IEC 61196-2.

• Q

  What are the main differences between control cable and power cable?

  A

  Feature	Control cable	Power cable
  Cores	many (2–61)	few (1–5)
  Cross-section	≤10mm² typical	up to thousands mm²
  Voltage rating	300/500V or 450/750V	0.6/1kV or higher
  Application	Signals, control panels	Power distribution
  Standard	IEC 60227, IEC 60502-1	IEC 60502-1

  Source: IEC 60227, IEC 60502.