Table 4F2A

90°C and 180°C Thermosetting Insulated Flexible Cables with Sheath, Non-Armoured (Copper Conductors)

Current-carrying Capacity (amperes):

Ambient Temperature: 30°C

Conductor Operating Temperature: 90°C

Conductor cross-sectional area Single-phase a.c. or d.c. Three-phase a.c. Single-phase a.c. or d.c.
1 two-core cable,
with or without protective conductor
1 three-core,
four-core or
2 single-core cables, touching
1 2 3 4
(mm2) (A) (A) (A)
4 42 37
6 55 49
10 76 66
16 103 89
25 136 119
35 146 200
50 146 200
50 177 250
70 225 310
95 273 369
120 316 432
150 363 497
185 414 567
240 487 673
300 560 773
400 924
500 1,062
630 1,242

Rating Factor for Ambient Temperature

90°C Thermoplastic or Thermosetting Insulated Cords:
Ambient Temperature: 35°C 40°C 45°C 50°C 55°C 60°C 65°C 70°C 75°C 80°C 85°C
Correction Factor: 0.95 0.91 0.86 0.82 0.76 0.70 0.64 0.57 0.50 0.40 0.28
180°C Thermosetting Insulated Cords:
Ambient Temperature: 35°C to 90°C 95°C 100°C 105°C 110°C 150°C 120°C 125°C 130°C 135°C
Correction Factor: 1.0 0.96 0.91 0.86 0.81 0.76 0.70 0.64 0.57 0.50
Ambient Temperature: 140°C 145°C

Correction Factor: 0.40 0.28


  1. The current ratings tabulated are for cables in free air but may also be used for cables resting on a surface. If the cable is to be wound on a drum on load the ratings should be reduced in accordance with Note 2 below and for cables which may be covered, Note 3 below.
  2. Flexible cables wound on reeling drums

    The current ratings of cables used on reeling drums are to be reduced by the following factors:

    a) Radial type drum b) Ventilated cylindrical type drum

    ventilated: 85% 1 layer of cable: 85%

    unventilated: 75% 2 layers of cable: 65%

    3 layers of cable: 45%

    4 layers of cable: 35%

    A radial type drum is one where spiral layers of cable are accommodated between closely spaced flanges; if

    fitted with solid flanges the ratings given above should be reduced and the drum is described as non-ventilated. If the flanges have suitable apertures the drum is described as ventilated.

    A ventilated cylindrical cable drum is one where layers of cable are accommodated between widely spaced flanges and the drum and end flanges have suitable ventilating apertures.

  3. Where cable may be covered over or coiled up whilst on load, or the air movement over the cable restricted, the current rating should be reduced. It is not possible to specify the amount of reduction but the table of rating factors for reeling drums can be used as a guide.
  4. For 180oC cables, the rating factors for ambient temperature allow a conductor operating temperature up to 150oC. Consult the cable manufacturer for further information.
  5. Where it is intended to connect the cables in this table to equipment or accessories designed to operate at a temperature lower than the maximum operating temperature of the cable, the cables should be rated at the maximum operating temperature of the equipment or accessory (see Regulations 512.1.5).
  6. Where it is intended to group a cable in this table with other cables, the cable should be rated at the lowest of the maximum operating temperatures of any of the cables in the group (see Regulations 512.1.5).

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