Discrimination of the direct current circuit s DB124247 Continuity of service of the solutions Discrimination of the direct current protection devices Discrimination is a key element that must be taken into account right from the design stage of a low-voltage installation to allow continuity of service of the electrical power. Discrimination involves coordination between two circuit s connected in series, so that in the event of a fault, only the circuit positioned immediately upstream of the fault trips. A discrimination current Is is defined as: bbi fault < Is: only D2 removes the fault, discrimination ensured, bbi fault > Is: both circuit s may trip, discrimination not ensured. 0 D2 Only D2 trips Is D1 and D2 trip I fault Discrimination may be partial or total, up to the breaking capacity of the downstream circuit. To ensure total discrimination, the characteristics of the upstream device must be higher than those of the downstream one. The same principles apply to designing both direct current and alternating current installations. Only the limit currents change when direct current is used. DB124248 Once again, we find the same concepts of discrimination: bbtotal: up to the breaking capacity of the downstream device. Our tests have been performed at up to 25 ka depending on the breaking capacity of the devices in question (20 ka pour C60H-DC), bbpartial: indication of the discrimination limit current Is. Discrimination is ensured below this value; above this value, the upstream device participates in the breaking process, bbnone: no discrimination ensured, the upstream and downstream circuit s will trip. Total discrimination solutions In the following tables, we offer you solutions that favour continuity of service (total discrimination between circuit s), for different short-circuit currents. For further information about the discrimination concept for protection devices in general, refer to technical supplement 557E4300, "Discrimination of modular circuit s". For further information about direct current applications, refer to technical supplement CA908032, " s for direct current applications". 1
Discrimination of the direct current circuit s Choice of the discrimination table Voltage Ue Tables Distribution with earthed polarity Distribution with earthed Protection non exigé Protection exigée mid-point In In In a a a Distribution isolated from earth In a Un R Un R Un/2 + Un/2 R Un R B A B A B A B A b C b C D b C Up to Up to 125 V DC Up to 250 V DC Tables 60 V page 3 Tables 125 V page 9 Tables 125 V page 9 ic60 1P + ic60 1P ic60 2P + ic60 2P ic60 2P + ic60 2P C120/NG125 1P + ic60 1P C120/NG125 2P + ic60 2P C120/NG125 2P + ic60 2P C60H-DC 1P + C60H-DC 1P C60H-DC 2P + C60H-DC 2P C60H-DC 2P + C60H-DC 2P C60H-DC 2P + C60H-DC 2P C120/NG125 1P + C60H-DC 1P C120/NG125 2P + C60H-DC 2P C120/NG125 2P + C60H-DC 2P C120/NG125 2P + C60HDC 2P ic60 2P + ic60 2P (see tables 60 V) ic60 3P + ic60 3P (see tables 60 V) ic60 2P + ic60 2P (see table 60 V) C120/NG125 2P + ic60 2P (see table 60 V) C60H-DC 2P + C60H-DC 2P C60H-DC 2P + C60H-DC 2P C60H-DC 2P + C60H-DC 2P C60H-DC 2P + C60H-DC 2P C120/NG125 2P + C60H-DC 2P C120/NG125 3P + C60H-DC 2P C120/NG125 2P + C60H-DC 2P C120/NG125 4P + C60H-DC 2P 2 Version : 1.1 CA908060E
: ic60 curve B : ic60 curves B, C, D ic60n/h/l Curve B In (A) 3 4 6 10 16 20 25 32 40 50 63 ic60n/h/l B 1 T T T T T T T T T T 2 T T T T T T T T 3 150 1200 T T T T T T 4 500 900 T T T T 6 300 700 1000 1800 4000 10 400 500 800 1000 u 16 C 1 T T T T T T T T T T 2 T T T T T T T T 3 150 1200 T T T T T T 4 400 900 T T T T 6 300 700 1000 1800 3000 10 300 500 700 800 u 16 D 1 T T T T T T T T T 2 1600 T T T T T T T 3 900 11000 T T T T T 4 700 T T T T 6 500 800 1800 3000 10 400 600 800 u 16 Note: This table can be used up to 125 V DC if ic60 (/) have 2 poles in serial to cut the current. 700 Discrimination limit = 700 A 3
: ic60 curve C : ic60 curves B, C, D ic60n/h/l Curve C In (A) 3 4 6 10 16 20 25 32 40 50 63 ic60n/h/l B 1 T T T T T T T T T T T 2 700 T T T T T T T T 3 900 T T T T T T T 4 900 8000 T T T T T 6 900 1800 3200 T T 10 700 800 1500 2000 16 1000 1200 C 1 T T T T T T T T T T T 2 500 T T T T T T T T 3 900 T T T T T T T 4 900 6700 T T T T T 6 700 1400 3200 T T 10 700 800 1500 2000 16 1000 1200 D 1 T T T T T T T T T T T 2 350 T T T T T T T T 3 700 T T T T T T T 4 700 4000 T T T T T 6 700 1400 3200 T T 10 500 800 1500 1800 16 1000 1200 Note: This table can be used up to 125 V DC if ic60 (/) have 2 poles in serial to cut the current. 700 Discrimination limit = 700 A 4 Version : 1.1 CA908060E
: ic60 curve D : ic60 curves B, C, D ic60n/h/l Curve D In (A) 3 4 6 10 16 20 25 32 40 50 63 ic60n/h/l B 1 T T T T T T T T T T T 2 1500 T T T T T T T T T 3 400 T T T T T T T T 4 700 T T T T T T T 6 700 1000 2500 T T T T 10 700 1400 1600 3600 9000 16 900 1000 1900 2700 C 1 T T T T T T T T T T T 2 1000 T T T T T T T T T 3 350 T T T T T T T T 4 700 T T T T T T T 6 700 1000 2000 T T T T 10 700 1400 1600 3600 9000 16 900 1000 1500 2100 D 1 T T T T T T T T T T T 2 700 T T T T T T T T T 3 350 T T T T T T T T 4 700 T T T T T T T 6 700 1000 2000 T T T T 10 700 1400 1600 3600 7400 16 900 1000 1500 2100 Note: This table can be used up to 125 V DC if ic60 (/) have 2 poles in serial to cut the current. 700 Discrimination limit = 700 A 5
: C120, NG125 curve B : ic60 curves B, C, D Curve B ic60n/h/l B 1 T T T T T T T T T T T 3 150 T T T T T T T T T T 4 300 500 1000 1250 T T T T T T 6 300 500 600 1800 2000 5500 T T T 10 700 700 1900 5000 9500 T 16 2000 3500 8500 20 2000 4200 u 25 C 1 T T T T T T T T T T T 3 120 T T T T T T T T T T 4 250 900 1100 1300 T T T T T T 6 500 500 1400 2000 4500 T T T 10 500 600 1500 5000 9000 T 16 1800 3000 7000 20 2000 3500 u 25 D 1 T T T T T T T T T T T 2 5000 T T T T T T T T T T 3 600 T T T T T T T T T 4 500 800 1000 T T T T T T 6 300 300 1100 1600 3500 T T T 10 400 400 1200 4000 8000 T 16 250 400 1400 2500 6000 20 600 1400 3500 u 25 Note: This table can be used up to 125 V DC if C120/NG125 and ic60 (/) have 2 poles in serial to cut the current. 700 Discrimination limit = 700 A 6 Version : 1.1 CA908060E
: C120, NG125 curve C : ic60 curves B, C, D Curve C ic60n/h/l B 1 T T T T T T T T T T T 3 5000 T T T T T T T T T T 4 1500 2000 T T T T T T T T 6 400 1500 3000 T T T T T T 10 1800 3000 8000 T T T 16 1000 1400 2500 15000 T T 20 6500 11500 T 25 4500 8500 15000 32 5000 8000 u 40 C 1 T T T T T T T T T T T 3 5000 T T T T T T T T T T 4 1000 1400 T T T T T T T T 6 400 1000 2400 T T T T T T 10 800 1500 3000 8500 T T T 16 800 1400 3000 15000 T T 20 1700 6500 11000 T 25 4500 8500 12000 32 3000 5000 7000 u 40 D 1 T T T T T T T T T T T 3 4000 T T T T T T T T T T 4 500 1000 T T T T T T T T 6 800 1900 T T T T T T 10 600 1200 2500 7000 T T T 16 500 1000 2500 12000 T T 20 1400 5500 9000 T 25 3500 7500 11000 32 3500 6000 u 40 Note: This table can be used up to 125 V DC if C120/NG125 and ic60 (/) have 2 poles in serial to cut the current. 500 Discrimination limit = 500 A 7
: C120, NG125 curve D : ic60 curves B, C, D Curve D ic60n/h/l B 1 T T T T T T T T T T T 3 T T T T T T T T T T T 4 5000 T T T T T T T T T T 6 1000 2000 T T T T T T T T 10 1000 9000 1400 3500 5000 T T T T 16 1500 2500 6000 T T T 20 2000 3500 T T T 25 15000 T T 32 9000 T T 40 7000 10000 T 50 10000 63 5000 C 1 T T T T T T T T T T T 3 T T T T T T T T T T T 4 5000 T T T T T T T T T T 6 1000 2000 T T T T T T T T 10 1000 9000 1400 3000 4000 15000 T T T 16 1500 2000 6000 T T T 20 3000 T T T 25 12000 T T 32 8000 T T 40 5000 9000 T 50 9000 63 4000 D 1 T T T T T T T T T T T 3 T T T T T T T T T T T 4 5000 T T T T T T T T T T 6 1000 2000 T T T T T T T T 10 1000 9000 1400 3000 4000 15000 T T T 16 1500 2000 6000 T T T 20 3000 T T T 25 12000 T T 32 8000 T T 40 5000 9000 T 50 9000 63 4000 Note: This table can be used up to 125 V DC if C120/NG125 and ic60 (/) have 2 poles in serial to cut the current. 5000 Discrimination limit = 5000 A 8 Version : 1.1 CA908060E
125 V DC : C60H-DC curve C : C60H-DC curve C Operating voltage (Ue): up to 125 V C60H-DC Curve C In (A) 1 2 3 4 6 10 16 20 25 32 40 50 63 C60H-DC C 0.5 T T T T T T T T T T T T T 1 250 T T T T T T T T 2 250 900 1800 11000 T T T T 3 300 500 700 1800 5000 T T 4 900 1300 3000 6000 6 1200 1800 u 10 Note: This table can be used up to 250 V DC if C60H-DC (/) have 2 poles in serial to cut the current. 500 Discrimination limit = 500 A 9
125 V DC : C120, NG125 curves B, C, D : C60H-DC curve C Operating voltage (Ue): up to 125 V Curve B C60H-DC C 0.5 500 T T T T T T T T T T 1 450 T T T T T T T T T 2 500 800 2500 T T T T T T 3 2400 4000 5000 T T T 4 800 1000 1500 5000 T T 6 1800 3000 7000 10 1500 3500 16 2500 Curve C C60H-DC C 0.5 T T T T T T T T T T T 1 1000 T T T T T T T T T T 2 5000 T T T T T T T T T 3 1800 T T T T T T T T 4 1300 5500 12000 T T T T T 6 2400 3000 6000 7000 12000 T T 10 3500 5500 8500 T 16 5500 9000 20 6000 25 5000 u 32 Curve D C60H-DC C 0.5 T T T T T T T T T T T 1 T T T T T T T T T T T 2 2500 6000 T T T T T T T T T 3 700 1500 7000 T T T T T T T T 4 1800 10000 12000 T T T T T T 6 2500 3000 4000 6000 7000 T T T 10 2000 3000 T T T 16 9000 T T 20 5000 T T 25 10000 T 32 5000 12000 40 6000 u 50 Note: These tables can be used up to 250 V DC if C120/NG125 and C60H-DC (/) have 2 poles in serial to cut the current. T Total discrimination. 500 Discrimination limit = 500 A 10 Version : 1.1 CA908060E
Discrimination of the direct current circuit s (cont.) TEvolutions his page must be removed before publishing 1.1 14/10/2016 New tables Sonovision 1.0 19/04/2016 Creation Sonovision Indice Date Modification Name 11