ACADEMIA DO CONHECIMENTO

Current Ratings & Volt Drop II – IEE

Table 4F1A 60°C Thermosetting Insulated Flexible Cables with Sheath, Non-Armoured - IEE

Table 4F1A

60°C Thermosetting Insulated Flexible Cables with Sheath, Non-Armoured

Current-carrying Capacity (amperes):

Ambient Temperature: 30°C Conductor Operating Temperature: 60°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 five-core 2 single-core cable
1 2 3 4
(mm2) (A) (A) (A)
4 30 26
6 39 34
10 51 47
16 73 63
25 97 83
35 102 140
50 124 175
70 158 216
95 192 258

Notes:

  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.

Table 4F1B 60°C Thermosetting Insulated Flexible Cables - IEE

Table 4F1B

60°C Thermosetting Insulated Flexible Cables

Voltage Drop (per ampere per metre):

Conductor Operating Temperature: 60°C

Conductor cross-sectional area Two-core cable d.c. Two-core cable, single-phase a.c. 1 three-core, four-core or five-core cable, three-phase a.c. 2 single-core cables, touching
d.c. Single-phase a.c.*
1 2 3 4 5 6
(mm2) (mV/A/m) (mV/A/m) (mV/A/m) (mV/A/m) (mV/A/m)
4 12 12 10
6 7.8 7.8 6.7
10 4.6 4.6 4.0
16 2.9 2.9 2.5
r x z r x z r x z
25 1.80 1.80 0.175 1.85 1.55 0.150 1.55
35 1.10 0.150 1.15 1.31 1.31 0.21 1.32
50 0.83 0.145 0.84 0.91 0.91 0.21 0.93
70 0.57 0.140 0.58 0.64 0.64 0.20 0.67
95 0.42 0.135 0.44 0.49 0.49 0.195 0.53

Note: * A larger voltage drop will result if the cables are spaced.

Table 4F2A 90°C and 180°C Thermosetting Insulated Flexible Cables with Sheath, Non-Armoured (Copper Conductors) - IEE

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
five-core
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 to90°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

Notes:

  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 drumsThe current ratings of cables used on reeling drums are to be reduced by the following factors:a) Radial type drum b) Ventilated cylindrical type drumventilated: 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).

Table 4F2B - IEE

Table 4F2B

Voltage Drop (per ampere per metre):

Conductor Operating Temperature: 90°C

Conductor
cross-sectional
area
1 two-core or 2 single-core cables 
d.c.
Two-core cable, single-phase a.c. 1 three-core,
four-core or
five-core cable, three-phase a.c.
2 single-core cables touching
Single-phase a.c.*
1 2 3 4 6
(mm2) (mV/A/m) (mV/A/m) (mV/A/m) (mV/A/m)
4 13.2 13.2 11.1
6 8.5 8.5 7.4
10 5.1 5.1 4.4
16 3.2 3.2 2.7
r x z r x z r x z
25 2.03 2.03 0.175 2.04 1.73 0.15 1.73
35 1.42 1.22 0.15 1.23 1.44 0.21 1.46
50 1.00 0.91 0.145 0.93 1.00 0.21 1.02
70 0.71 0.62 0.14 0.64 0.71 0.20 0.73
95 0.54 0.47 0.135 0.49 0.54 0.195 0.57
120 0.42 0.37 0.135 0.39 0.42 0.190 0.46
150 0.34 0.29 0.130 0.32 0.34 0.190 0.39
185 0.27 0.24 0.130 0.27 0.27 0.190 0.33
240 0.21 0.188 0.130 0.23 0.21 0.185 0.28
300 0.167 0.147 0.125 0.195 0.173 0.180 0.25
400 0.127 0.132 0.175 0.22
500 0.100 0.107 0.170 0.20
630 0.074 0.085 0.170 0.190

Notes:

  1. The voltage drop figures given above are based on a conductor operating temperature of 90°C and are therefore not accurate when the operating temperature is in excess of 90°C. In the case of the 180°C cables with a conductor temperature of 150°C the above resistive values should be increased by a factor of 1.2.
  2. *A larger voltage drop will result if the cables are spaced.

Table 4F3A Flexible Cords, Non-Armoured - IEE

Table 4F3A

Flexible Cords, Non-Armoured

Conductor
cross-sectional 
area
Current-carrying capacity Maximum mass supportable by
twin flexible cord (see Regulations
522.7.2 and 559.6.1.5)
Single-phase a.c. Three-phase a.c.
1 2 3 4
(mm2) (A) (A) (kg)
0.5 3 3 2
0.75 6 6 3
1 10 10 5
1.25 13 5
1.5 16 16 5
2.5 25 20 5
4 32 25 5

Where cable is on a reel see the notes to the table in 4F1A.

Rating Factor for Ambient Temperature

60°C Thermoplastic or Thermosetting Insulated Cords:

Ambient Temperature: 35°C 40°C 45°C 50°C 55°C
Correction Factor: 0.91 0.82 0.71 0.58 0.41

90°C Thermoplastic or Thermosetting Insulated Cords:

Ambient Temperature: 35°C to 50°C 55°C 60°C 65°C 70°C
Correction Factor: 1.0 0.96 0.83 0.67 0.47

180oC Thermosetting Insulated Cords:

Ambient Temperature: 35°C to 120°C 125°C 130°C 135°C 140°C 145°C
Correction Factor: 1.0 0.96 0.85 0.74 0.60 0.42

Glass Fibre Cords:

Ambient Temperature: 35°C to 150°C 155°C 160°C 165°C 170°C 175°C
Correction Factor: 1.0 0.92 0.82 0.71 0.51 0.40

Table 4F3B - IEE

Table 4F3B

Voltage Drop (per ampere per meter):

Conductor Operating Temperature: 60°C*

Conductor cross-sectional area d.c. or single-phase a.c. Three-phase a.c.
1 2 3
(mm2) (mV/A/m) (mV/A/m)
0.5 93 80
0.75 62 54
1 46 40
1.25 37
1.5 32 27
2.5 19 16
4 12 10

Note:

* The tabulated values above are for 60°C thermoplastic or thermosetting insulated flexible cables and for other types of flexible cable they are to be multiplied by the following factors:

For 90°C thermoplastic or thermosetting insulated 1.09

150°C 1.31

185°C glass fibre 1.43