Current Carrying Capacity of Cables with Improved Characteristics in Case of Fire

acc. to HD 604 S1 and HD 627, part 7H
The HD 604 and HD 627 are identical to DIN VDE 0276-604, respectively DIN VDE 0276-627.

Bayka products
The values given below are applicable to these products:

Column N2XH [copper, without concentric conductor and braid] (with CPR or nonfire):

feedIN DC
(without concentric conductor)
Power Soil Telekom-Power

Column N2XCH/N2XCWH [copper, with concentric conductor or braid] (with CPR or nonfire):

feedIN DC (with concentric conductor) feedIN DC EMC soilblack EMC soilblack VFD EMC

General

This section applies to the  capacity under both agreed but also deviating conditions, provided that three cores are loaded in three-phase operation or only one single-core cable is loaded in DC operation.

The rated currents listed in the tables are recommended values ​​under normal operating conditions.

General Conditions

Temperatures °C (conductor)
maximum admissible operating temperature +90
maximum admissible temperature in case of short circuit +250

Concentric conductors are grounded on both ends.

Operating frequency 50 Hz.

The tabulated loading capacities ​​are based on various conditions such as

– operating mode,

– laying conditions,

– environmental conditions.

In the event of deviating operating conditions, the loading capacities ​​are to be multiplied by suitable conversion factors, which are based on the same calculation principles and operating conditions as the given values.

Current-Carrying Capacities of Cables with Improved Characteristics in Case of Fire

Laying in air(30°C)

recommended values acc. to HD 604 S1, table B.1

N2XH

[copper, without concentric conductor and braid]
N2XCH / N2XCWH

[copper, with concentric conductor or braid]
number of
loaded
cores
3 3 1 3 3
cross-section
mm²
copper conductor
rated current in A
1,5 26 24 33 27 25
2,5 34 32 43 36 33
4 44 42 57 47 43
6 56 53 72 59 54
10 77 74 99 81 75
16 102 98 131 109 100
25 138 133 177 146 136
35 170 162 217 179 165
50 207 197 265 218 201
70 263 250 336 275 255
95 325 308 415 336 314
120 380 359 485 388 364
150 437 412 557 438 416
185 507 475 646 501 480
240 604 564 774 580 565
300 697 649 901 654 643
400 811 761 1060 733 737
500 940 866 1252 825 807

*) rated current in DC plants with far off return conductor

Current Carrying Capacity of Cables with Improved Characteristics in Case of Fire

Admissible short-circuit temperatures and rated short-circuit current densities

recommended values acc. to HD 604 S1, table B.2

cables with admissible short-circuit temperature
°C
rated short-circuit current densities in A/mm²
for a rated short-circuit duration of 1s
conductor temperature at the beginning of short-circuit in °C
90 80 70 60 50 40 30 20
copper conductor 250 143 149 154 159 165 170 176 181

Conversion factors for different numbers of loaded cores of multi-core cables in air

The following applies to three loaded cores:
HD 604, Part 5, main section G, attachment B (Current carrying capacity) and attachment B, Table B.1 (rated current capacity, cable in air), column 3 and column 5.

acc. to HD 627 S1, part 7H, table A.1

number of loaded cores
Laying
in air
5 0,75
7 0,65
10 0,55
14 0,50
19 0,45
24 0,40
40 0,35
61 0,30