| Full title | Tests on electric and optical fibre cables under fire conditions. Part 1-2: Test for vertical flame propagation for a single insulated wire or cable. Procedure for 1 kW pre-mixed flame |
| Publisher | IEC (TC 20); adopted as EN by CENELEC and as BS EN by BSI |
| Current edition | BS EN 60332-1-2:2004+A12:2020 (EN 60332-1-2:2004 with A1:2015, A11:2016 and A12:2020) |
| Latest IEC edition | IEC 60332-1-2:2025, edition 2.0, published 10 June 2025 |
| Apparatus | IEC 60332-1-1 (EN 60332-1-1) |
| Related standards | EN 13501-6, EN 50399, EN 60332-1-3, EN 60332-2-2, EN IEC 60332-3 series |
What it covers
EN 60332-1-2 sets out a test for the resistance of a single vertical insulated wire or cable, or an optical fibre cable, to vertical flame propagation. It uses a 1 kW pre-mixed flame. The apparatus is described in Part 1-1.
The procedure may not suit conductors smaller than 0.5 mm² total cross-section, or small optical fibre cables, because the conductor can melt before the test ends. For these, the diffusion flame test in EN 60332-2-2 is recommended.
The standard notes that passing a single cable test does not show how a bunch of the same cables will behave. Bunched cables are covered by the EN IEC 60332-3 series.
The test procedure
| Item | Requirement |
|---|---|
| Test piece | Single insulated conductor or cable, (600 ± 25) mm long |
| Mounting | Held vertical in a metal screen enclosure, fixed to two horizontal supports (550 ± 5) mm apart |
| Burner | 1 kW pre-mixed propane burner, at (45 ± 2)° to the vertical axis of the cable |
| Flame position | Tip of the inner blue cone touches the cable (475 ± 5) mm below the lower edge of the top support |
| Flame application | Continuous, for a time set by the cable’s overall diameter (see below) |
Flame application time
| Overall diameter D | Flame application time |
|---|---|
| D ≤ 25 mm | 60 s |
| 25 mm < D ≤ 50 mm | 120 s |
| 50 mm < D ≤ 75 mm | 240 s |
| D > 75 mm | 480 s |
The diameter is measured to EN 60811-203. Non-circular cables use an equivalent diameter worked out from their dimensions.
Evaluating the result
After all burning has stopped, the cable is wiped clean. Soot that wipes off to leave an undamaged surface is ignored, as is softening or deformation. The distances from the lower edge of the top support to the upper and lower onset of charring are measured. The onset of char is where the surface changes from resilient to brittle when pressed with a sharp blade.
The recommended performance requirement in Annex A is that the distance from the lower edge of the top support to the upper onset of charring is greater than 50 mm. The cable also fails if burning extends downwards more than 540 mm below the lower edge of the top support.
In the 2004 edition (the current BS EN), Annex A is informative, so product standards and specifications decide whether it is applied as a pass criterion. In IEC 60332-1-2:2025, Annex A is normative.
Use in CPR classification
Under EN 13501-6, EN 60332-1-2 provides the flame spread value H:
| Class | EN 60332-1-2 requirement |
|---|---|
| B1ca, B2ca, Cca, Dca | H ≤ 425 mm, plus EN 50399 |
| Eca | H ≤ 425 mm (this test only) |
| Fca | H > 425 mm |
So every cable from Eca upwards must achieve H ≤ 425 mm in this test. Eca is the class reached with EN 60332-1-2 alone.
Editions
- BS EN 60332-1-2:2004+A12:2020 is the current BSI version, identical to EN 60332-1-2:2004/A12:2020. It is based on IEC 60332-1-2:2004 and IEC Amendment 1:2015.
- IEC 60332-1-2:2025 (edition 2.0) cancels and replaces the 2004 edition and Amendment 1. Its listed technical changes are a change to the positioning of test pieces that move out of the flame, and the addition of performance requirements in Annex A.
- At the time of writing, no EN adoption of the 2025 IEC edition was found. Check the EN status before quoting the 2025 edition in a European specification.
What it means in practice
- A datasheet claim of “flame retardant to IEC 60332-1” means a single cable passed this test. It says nothing about smoke, acidity or bunched flame spread.
- On a CPR label, Eca is the minimum class that includes a pass in this test.
- Testing to EN 60332-1-2 can be done at the same time as EN 60332-1-3, which looks at flaming droplets and particles.
Related reading: What is LSZH cable and when do you need it?.