Installation method F according table B.52.1.
Single-core cables, touching in free air
Clearance to wall not less than one cable diameter
Maximum allowed current in function of the ambient temperature for installation method F
Ambient temperature
Cable section
30 °C
40 °C
45 °C
50 °C
55 °C
25 mm²
< 110 A
< 96 A
< 87 A
< 78 A
< 67 A
35 mm²
< 137 A
< 119 A
< 108 A
< 97 A
< 84 A
50 mm²
< 167 A
< 145 A
< 132 A
< 119 A
< 102 A
70 mm²
< 216 A
< 188 A
< 171 A
< 153 A
< 132 A
95 mm²
< 264 A
< 230 A
< 209 A
< 187 A
< 161 A
120 mm²
< 308 A
< 268 A
< 243 A
< 219 A
< 188 A
Calculation method for IEC:
• Single supply cables (3 PE - configuration (1)):
• Add 10 % to the total compressor current (I
tot
Pack or I
tot
FF from the tables)
• Install the prescribed fuse on each cable
• Parallel supply cable (2 x 3 PE - configuration (2)):
• Add 10 % to the total compressor current (I
tot
Pack or I
tot
FF from the tables) and divide 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 PE as in (3):
• Add 10 % to the total compressor current (I
tot
Pack or I
tot
FF from the tables) and divide 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
tot
= 89 A, maximum ambient temperature is 45 °C, recommended fuse = 100 A
• Single supply cables (3 PE - configuration (1)):
• I = 89 A + 10 % = 89 x 1.1 = 97.9 A
• The table for B2 and ambient temperature = 45 ° C allows a maximum current of 93 A for a 50
mm² cable. For a cable of 70 mm², the maximum allowed current is 118 A, which is sufficient.
Therefore, use a 3 x 70 mm² + 35 mm² cable.
If method C is used, 50 mm² is suffficient. (35 mm² for method F) => cable 3 x 50 mm² + 25
mm².
• Parallel supply cable (2 x 3 PE - configuration (2)):
• I = (89 A + 10 %)/2 = (89 x 1.1)/2 = 49 A
• For a cable of 25 mm², B2 at 45 °C, the maximum current is 63 A x 0.8 = 50.4 A. So 2 parallel
cables of 3 x 25 mm² + 25 mm² are sufficient.
• Install 50 A fuses on each cable instead of 100 A.
Instruction book
2920 7101 41
89
Summary of Contents for CPC 40 G
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