Atlas Copco GA 11+ Instruction Book page 135

Instruction book
Cable section
70 mm²
95 mm²
120 mm²
Maximum allowed current in function of the ambient temperature for installation method F
Cable section
25 mm²
35 mm²
50 mm²
70 mm²
95 mm²
120 mm²
Calculation method for IEC:
• Single supply cables (3 phases + PE - configuration (1)):
• Add 10 % to the total compressor current (I
• Install the prescribed fuse on each cable
• Parallel supply cable (2 x 3 phases + PE - configuration (2)):
• Add 10 % to the total compressor current (I
by 2
• Multiply the ampacity of the cables with 0.8 (see table A.52.17 (52-E1))
• Install fuses of half the size of the recommended maximum fuse size on each cable.
• When using 2 x 3 phases + PE as in (3):
• Add 10 % to the total compressor current (I
by √3
• Multiply the ampacity of the cables with 0.8 (see table A.52.17 (52-E1))
• Fuse size: the recommended maximum fuse size divided by √3 on each cable.
• Size of the PE cable:
• For supply cables up to 35 mm²: same size as supply cables
• For supply cables larger than 35 mm²: half the size of the supply wires
Always check the voltage drop over the cable (less than 5 % of the nominal voltage is
recommended).
Example: I = 89 A, maximum ambient temperature is 45 °C, recommended fuse = 100 A
tot
• Single supply cables (3 phases + PE - configuration (1)):
• I = 89 A + 10 % = 89 x 1.1 = 97.9 A
2920 7118 31
Ambient temperature
30 °C 40 °C
< 184 A < 160 A
< 223 A < 194 A
< 259 A < 225 A
Installation method F according table B.52.1.
Single-core cables, touching in free air
Clearance to wall not less than one cable diameter
Ambient temperature
30 °C 40 °C
< 110 A < 96 A
< 137 A < 119 A
< 167 A < 145 A
< 216 A < 188 A
< 264 A < 230 A
< 308 A < 268 A
45 °C 50 °C
< 145 A < 131 A
< 176 A < 158 A
< 205 A < 184 A
45 °C 50 °C
< 87 A < 78 A
< 108 A < 97 A
< 132 A < 119 A
< 171 A < 153 A
< 209 A < 187 A
< 243 A < 219 A
Pack or I FF from the tables)
tot tot
Pack or I FF from the tables) and divide
tot tot
Pack or I FF from the tables) and divide
tot tot
55 °C
< 112 A
< 136 A
< 158 A
55 °C
< 67 A
< 84 A
< 102 A
< 132 A
< 161 A
< 188 A
133