EC-E...

103906_en_01

PHOENIX CONTACT

9

3.7

Safe shutdown

Safe shutdown of the EC-E... with different supply line lengths and cable cross-sections

Specific electrical resistance for electrolytic copper:

ρ0 = 0.0178 (Ω x mm²)/m

U

The voltage drop on the EC-E... and the tolerance of the shutdown point

(typically 1.1 x I

EC-E... nominal current setting I

3 A

6 A

→ EC-E... typically shuts down after 3 s

E.g., shutdown current I

3.75 A

7.5 A

R

*

→

*

Internal resistance of miniature circuit-breakers

5.07

Ω

2.51

Ω

EC-E... trips safely from 0

Ω up to max. circuit resistance R

max

Cable cross-section A in mm²

→ 0.14 mm² 0.25 mm² 0.34 mm² 0.5 mm² 0.75 mm²

1 mm²

1.5 mm²

Length L in meters

(= single length)

0

Total cable resistance in ohms = (R

0

0

0

0

0

0

0

5 m

1.27

Ω

0.71

Ω

0.52

Ω

0.36

Ω

0.24

Ω

0.18

Ω

0.12

Ω

10 m

2.54

Ω

1.42

Ω

1.05

Ω

0.71

Ω

0.47

Ω

0.36

Ω

0.24

Ω

15 m

3.81

Ω

2.14

Ω

1.57

Ω

1.07

Ω

0.71

Ω

0.53

Ω

0.36

Ω

20 m

5.09

Ω

2.85

Ω

2.09

Ω

1.42

Ω

0.95

Ω

0.71

Ω

0.47

Ω

25 m

6.36

Ω

3.56

Ω

2.62

Ω

1.78

Ω

1.19

Ω

0.89

Ω

0.59

Ω

30 m

7.63

Ω

4.27

Ω

3.14

Ω

2.14

Ω

1.42

Ω

1.07

Ω

0.71

Ω

35 m

8.90

Ω

4.98

Ω

3.66

Ω

2.49

Ω

1.66

Ω

1.25

Ω

0.83

Ω

40 m

10.17

Ω

5.70

Ω

4.19

Ω

2.85

Ω

1.90

Ω

1.42

Ω

0.95

Ω

45 m

11.44

Ω

6.41

Ω

4.71

Ω

3.20

Ω

2.14

Ω

1.60

Ω

1.07

Ω

50 m

12.71

Ω

7.12

Ω

5.24

Ω

3.56

Ω

2.37

Ω

1.78

Ω

1.19

Ω

75 m

19.07

Ω

10.68

Ω

7.85

Ω

5.34

Ω

3.56

Ω

2.67

Ω

1.78

Ω

100 m

25.34

Ω

14.24

Ω

10.47

Ω

7.12

Ω

4.75

Ω

3.56

Ω

2.37

Ω

125 m

31.79

Ω

17.80

Ω

13.09

Ω

8.90

Ω

5.93

Ω

4.45

Ω

2.97

Ω

150 m

38.14

Ω

21.36

Ω

15.71

Ω

10.68

Ω

7.12

Ω

5.34

Ω

3.56

Ω

175 m

44.50

Ω

24.92

Ω

18.32

Ω

12.46

Ω

8.31

Ω

6.23

Ω

4.15

Ω

200 m

50.86

Ω

28.48

Ω

20.94

Ω

14.24

Ω

9.49

Ω

7.12

Ω

4.75

Ω

225 m

57.21

Ω

32.04

Ω

23.56

Ω

16.02

Ω

10.68

Ω

8.01

Ω

5.34

Ω

250 m

63.57

Ω

35.60

Ω

26.18

Ω

17.80

Ω

11.87

Ω

8.90

Ω

5.93

Ω

Example 1: Max. permissible length at 1.5 mm² and 3 A

→

Approx. 200 m

†

†

Shutdown current I

Max. current resistance R

R

The value calculated, 5.07

Ω, falls between 200 m and 225 m in the table (4.75 Ω and 5.34 Ω).

This means that you can bridge 200 m comfortably.

Example 2: Max. permissible length at 1.5 mm² and 6 A

→

Approx. 100 m

Example 3: Mixed wiring:

(control cabinet--- sensor/actuator level)

R1 = 40 m in 1.5 mm² and R2 = 5 m in 0.25 mm²

R1 = 0.95 ohms, R2 = 0.71 ohms

Total (R1 + R2) = 1.66 ohms