faq

• Q

  What is the flame retardancy standard for bunched cables? How does it differ from single cable?

  A

  Bunched cables are tested to IEC 60332-3 (or EN 50399).

  Method: Multiple cables bundled vertically on a ladder, exposed to 20.5kW flame for 20 or 40 minutes.
  Measures: Flame spread, heat release, smoke production.
  Difference: Much more stringent than single cable test.

  Source: IEC 60332-3 series & EN 50399.

• Q

  Why do some cables state “IEC 60332-1 compliant”? What does it mean?

  A

  IEC 60332-1 is a single vertical burn test.
  Method: 60cm sample vertically, 1kW flame for 60 seconds.
  Pass criteria: Self-extinguishment and distance from lower edge of upper clamp to start of charring >50mm.
  Note: For single cables only, not for bunched cables.

  Source: IEC 60332-1:2015.

• Q

  How much more expensive is LSZH cable compared to PVC cable? Why?

  A

  LSZH cable is typically 20–30% more expensive than equivalent PVC cable. Reasons:

         —Higher raw material cost (special polyolefin compounds)

         —More demanding processing (dedicated extrusion lines)

         —Costly flame retardant & smoke suppressant additives

  Source: Industry average cost analysis.

  
  

• Q

  How to calculate voltage drop? What is the formula?

  A

  Single-phase voltage drop formula: ΔV = 2 × I × R × L / 1000 (volts)
  I = current (A), R = conductor DC resistance (Ω/km, from IEC 60228), L = length (m).
  Max allowed drop: typically 5%.
  Example: 2×1.5mm² copper, 10A, 50m, R≈12.1Ω/km → ΔV = 2×10×12.1×50/1000 = 12.1V (exceeds 5% for 220V, need larger cross-section).

  Source: IEC 60364-5-52 & IEC 60228.

• Q

  How does cable cross-section affect ampacity? Is there a quick estimation method?

  A

  Quick reference (copper PVC, single-phase, 30°C air):

  Area (mm²)	Ampacity (A)
  1.5	14.5
  2.5	19.5
  4	26
  6	34
  10	46

  Correction factors (multiply):
  - Ambient 35°C → 0.94 ; 40°C → 0.87
  - Grouping (6 circuits) → 0.8
  - Conduit installation → 0.8 (steel) or 0.9 (PVC)

  Formula: I = k × I₀

  Source: IEC 60364-5-52 Table B.52.2 & B.52.17.

• Q

  What are the application scenarios for CPR fire classes Eca, Dca, Cca, B2ca?

  A

  Per EN 13501-6:

  Class	Flame spread	Heat release	Smoke	Droplets	Typical use
  Eca	not required	not required	none	none	Low-risk non-residential
  Dca	≤ 1.5 m	≤ 30 MJ/m²	none	none	Residential wiring
  Cca	≤ 1.0 m	≤ 15 MJ/m²	s1/s2 optional	d0/d1 optional	Hospitals, schools
  B2ca	≤ 0.5 m	≤ 7.5 MJ/m²	s1 required	d0 required	High-rise, tunnels

  Source: EN 13501-6 & CPR guidelines.