Miniature Circuit-Breakers (MCBs)

Transcription

1 Product Overview Miniature Circuit-Breakers (MCBs) Design Tripping characteristics Rated current I n Rated breaking capacity Power supply company product range 5SP3 E 16 - A Standard product range 5SQ2 B 6-40 A C A 5SQ3 C A 5SX2 A 1-40 A B 6-50 A C A D A 5SX4 B 6-50 A C A AC/DC product range 5SX5 B 6-32 A C A High current product range 5SX7 B A C A D 40 - A Energy limitation class T Definitions 1 MW =Modular width of 18 mm N-type =Device mounting depth of 55 mm Depth 70 mm= Device mounting depth 70 mm 2/2 Siemens I

2 Summary of Technical Data Tripping characteristics 5SX2 5SX4 5SX5 5SX7 A, B, C, D B, C B, C B, C, D No. of poles N 3 + N Rated voltage V AC 230/400 V DC - 220/440 - Operating voltage min. AC/DC V 24 max. DC V/pole 60 1) ) max. AC V 440 Rated breaking capacity acc. to DIN VDE 0641 AC ka DC ka Insulation coordination Rated insulation voltage AC V 250/440 Degree of pollution for overvoltage category III 2 3 Degree of protection IP 00 according to DIN , IP 40 when mounted in distribution boards Flammability Category IIb according to DIN VDE 0304 Part 3 Mounting 1) r Battery charging voltage 72 V. On a 35 mm mounting rail (DIN EN ); for 5SX7, also screw mounting Terminals Tunnel terminals on both ends; 5SX2, 5SX4, 5SX5 combined terminal below for simultaneous connection to busbars (fork-type) and feeder cables Conductor cross sections Solid and stranded, max. Upper terminal mm Lower terminal mm Finely stranded with end sleeves, max. Upper terminal mm Lower terminal mm Terminal tightening torque max. Nm Supply connection As required, observe the polarity for DC applications Mounting position As required Service life On the average operations at rated load Ambient temperature C -25 to +45, occasionally +55, max. 95 % humidity, storage temperature: -40 to +75 Resistance to climate According to IEC , 6 cycles Resistance to vibration m/s 2 60 at 10 Hz to 150 Hz according to IEC Siemens I /3

3 Applications MCBs of the N System primarily protect cables and conductors against overload and short circuit. Thus, they also protect electrical equipment against overheating according to DIN VDE 0 Part 430. Under certain conditions, MCBs also protect against shock currents caused by excessive touch voltage due to insulation failure according to DIN VDE 0 Part 410. Further, due to the fixed rated current settings of MCBs, it is also possible to protect motors in a limited form. For the respective application, there are four different tripping characteristics available which will be individually described. The standards EN , DIN VDE 0641 Part 11 and IEC form the basis for the design and approval of the MCBs. For applications in industry and in system and plant engineering where MCBs of the N System are used, add-on accessories are available, such as auxiliary contacts (AC), fault signal contacts (FC), shunt trips (ST), undervoltage releases (UR) and RCCB modules. Functional design, mode of operation MCBs of the N System operate using a delayed overload current/time-dependent thermal release (thermal bimetal) for low overcurrents and an instantaneous electromagnetic release for higher overload and shortcircuit currents. The special contact materials used assure a long service life and offer a high level of protection against contact welding. MCBs of the N System significantly limit the let-through current when a fault occurs due to the ultra-fast contact separation and the quick quenching of the arc in the arc-chamber. Thus, generally, they fall below the permissible limiting I 2 t values of energy limiting class 3, specified in DIN VDE 0641 Part 11 by 50%. This guarantees excellent selectivity with the upstream overcurrent protective devices. Features High rated breaking capacity up to A according to EN Excellent current limiting and selectivity Tripping characteristics A, B, C and D Add-on accessories, quick mounting on site using snapon mechanism Combined terminal allows busbar and feeder cable to be simultaneously connected Disconnector characteristics according to DIN VDE 0660 Part 107 (5SX7) Main switch characteristics according to EN (5SX7) Separate switch position indicator (5SX7) The terminals are safe from finger touch and safe from touch by the back of the hand acc. to DIN VDE 0106 Part Insertion guide for fast and easy access to the terminal Handle locking device effectively prevents unauthorized operation of the handle 2/4 Siemens I

4 Application examples Feeder cables from below with cross sections up to 25 mm 2 and 3-pole 5ST2 144 busbars can be simultaneously connected at the combined terminal of the MCB. Feeder cables from below with cross sections up to 35 mm 2 and double-pole 5ST2 143 busbars can be simultaneously connected using the terminal 5ST Cables connected from the top use the same principle. Feeder cables from above with cross sections up to 35 mm 2 can be connected to 5ST2 144 busbars through supplementary terminal 5ST Feeder cables with cross sections up to 25 mm 2 and 5ST2 165 busbars can be simultaneously connected at the combined terminal of the MCB using the auxiliary contacts mounted on-site. Siemens I /5

5 Cable protection The task of MCBs is to protect cables and conductors against thermal overload of the insulation due to overcurrents and short circuits. The tripping characteristics of the MCBs match the load curves of the cables and conductors. 1 st condition I b I n I z 2 nd condition I I z The following explanation describes the relative value of the cable/conductors and the MCBs. In the standards EN /1991 and IEC /1987, modified in 11/91, the new characteristics B, C and D were defined, and adopted in DIN VDE 0641 Part 11/8.92. Therefore, all three characteristics can be certified. Characteristic B replaces the earlier characteristic L. The characteristic G according to CEE 19, 1 st edition is still defined, but in practice it is going to be replaced by characteristic C. In the field, the new tripping characteristics with their common thermal release operating level I 2 = 1.45 x I n provide the advantage that the miniature circuit-breakers for the protection of cables and conductors can be more easily and clearly assigned in case of overload, and more specifically, according to the condition: I n I z. I b Operating current: current determined by the load at fault-free operation I z Permissible continuous current of a conductor for which the continuous limit temperature of the insulation is not exceeded 1.45 x I z Maximum permissible time-limited overload current at which the insulation properties are not reduced in a safety-relevant way if the continuous limit temperature is briefly exceeded I n Rated current: Current for which the circuit-breaker has been designed and to which other rated quantities are referred I 1 Low test current: A current, which does not lead to tripping under defined conditions I 2 High test current: A current, which trips the device within one hour (I n 63 A) under defined conditions I 3 Tolerance limits I 4 Holding current of the instantaneous release (short-circuit release) I 5 Tripping current of the instantaneous release (short-circuit release) Conductor cross sections Assignment of MCBs according to DIN VDE 0641 Part 11 to copper conductors with PVC insulation for installation type C 1) and R= 30 C: Rated cross section Rated current MCB I z (conductor) Continuous current in A acc. to DIN VDE 0298 T4 and DIN VDE 0 T430 Supplement sheet 1 2 conductors 3 conductors 2 conductors 3 conductors mm 2 A A A A ) Example: Rising, multi-core conductors on/in the wall. 2/6 Siemens I

6 Tripping characteristics according to EN , DIN VDE 0641 Part 11 Tripping characteristic A For limited semiconductor protection Protection of measuring circuits with transformers Protection of circuits with long cable lengths which will require tripping within 0.4 s according to DIN VDE 0 Part 410 Tripping characteristic B Cable and line protection mainly in residential buildings, proof regarding shock-hazard protection is not necessary Tripping characteristic C Cable and line protection, advantageous in case of higher inrush currents, e.g. lamps, motors Tripping characteristic D For applications involving equipment generating significant pulses, e.g. transformers, solenoid valves, capacitances Siemens I /7

7 Tripping characteristics Tripping performance at an ambient temperature of 30 C Tripping Standards Thermal release Electromagnetic release characteristics Test currents: Test currents: Low test High test Tripping time Hold Trips at the Tripping time current current 63 A I n 125 A latest at I 1 I 2 t I 4 I 5 t A 1.13 x I n > 1 h > 2 h 2 x I n 0.1 s 1.45 x I n < 1 h < 2 h 3 x I n < 0.1 s B IEC /EN x I n > 1 h > 2 h 3 x I n 0.1 s DIN VDE 0641 Part x I n < 1 h < 2 h 5 x I n < 0.1 s C 1.13 x I n > 1 h > 2 h 5 x I n 0.1 s 1.45 x I n < 1 h < 2 h 10 x I n < 0.1 s D 1.13 x I n > 1 h > 2 h 10 x I n 0.1 s 1.45 x I n < 1 h < 2 h 20 x I n < 0.1 s (IEC : 50 x I n) At other ambient temperatures, the currents of the delayed tripping change by approximately 5 % for each 10 K temperature difference. More specifically they increase for temperatures below 30 C and decrease for temperatures above 30 C. For DC, the limit currents of the instantaneous tripping increase by a factor of 1.2. If more than one circuit in a series of MCBs is loaded, this has an impact on the characteristic as a result of an increased ambient temperature. In this case, an additional correction factor must be applied, referred to the rated miniature circuit-breaker current. No > 7 K Rated breaking capacity For MCBs, there are special requirements with regard to the breaking capacity. The values are standardized and are determined according to the testing conditions of EN and DIN VDE 0641 Part 11. The most usual values are and For other reference voltages and other simpler test conditions, other values can be specified which lie above those of EN and DIN VDE 0641 Part 11. An example of another standard is EN or DIN VDE 0660 Part 101 for MCBs. Rated breaking capacity EN (IEC ) EN (IEC ) 1-pole 2, 3, 4-pole 1-pole 2, 3, 4-pole 230 V AC 230 V AC 400 V AC 230 V AC 230 V AC 400 V AC Rated current I n [A] I cn [ka] I cn [ka] I cn [ka] I cu [ka] I cu [ka] I cu [ka] 5SX SX SX E DIN VDE 0641 T 12 E DIN VDE 0641 T 12 1-pole 2-pole 1-pole 2-pole 230 V AC 400 V AC 220 V AC 440 V AC Rated current I n [A] I cn [ka] I cn [ka] I cn [ka] I cn [ka] 5SX ) 10 1) 1) Time constant 4 ms. 2/8 Siemens I

8 Selectivity, miniature circuit-breakers/fuses Generally, distribution networks Selectivity means, that in the are configured as radial networks. An overcurrent device protective device in the vicinity event of a fault, only the must be provided at each reduction of the conductor cross current paths can continue to of the fault trips. Thus, parallel section. This results in a cascade graded according to the For MCBs with upstream fuses, provide the necessary power. rated current, which should, the selectivity limit essentially where possible, provide selectivity. and tripping characteristics of depends on the current limits the MCB as well as on the pre-arcing I 2 t value of the fuse. Therefore, MCBs with different characteristics and rated breaking capacities also have different selectivity limits. The subsequent tables show the currents up to which selectivity is provided between MCBs and upstream fuses according to DIN VDE 0636 Part 21. The values specified in ka are limit values which have been determined under unfavourable test conditions. In practice, better values can be obtained, depending on the type of the upstream fuse. Limit values of the MCBs/fuses selectivity in ka Downstream MCBs Upstream fuses I n [A] 16 A 20 A 25 A 35 A 50 A 63 A 80 A A 5SX2 Characteristic A Characteristic B Characteristic C Characteristic D r Rated breaking capacity 5SX2 according to EN Siemens I /9

9 Selectivity MCBs/fuses In the event of a short circuit when using the MCBs 5SX4, 5SX7 and fuses according to DIN VDE 0636 Part 21 selectivity is provided up to the indicated values in ka. Limit values of the MCBs/fuses selectivity in ka Downstream MCBs Upstream fuses I n [A] 16 A 20 A 25 A 35 A 50 A 63 A 80 A A 125 A 5SX4 Characteristic B Characteristic C r Rated breaking capacity 5SX4 according to EN Limit values of the MCBs/fuses selectivity in ka Downstream MCB Upstream fuse I n [A] A 125 A 160 A 200 A 224 A 250 A 5SX7 Characteristic B Characteristic C Characteristic D r Rated breaking capacity 5SX7 according to EN /10 Siemens I

10 Selectivity MCBs/circuit-breakers Distribution networks can also In this case, the selectivity limit be configured without any depends on the level of the fuses. In these cases, a peak current Î of the miniature circuit-breaker acts like an circuit breaker and on the tripping current of the circuit-break- upstream protective device. er. Limit values of the MCBs/circuit-breakers selectivity in ka The following tables specify the short-circuit currents in ka up to which selectivity is provided between the MCBs and upstream circuit-breakers according to IEC and DIN VDE 0660, Part 101 at 230/400 V AC. Downstream MCBs Upstream circuit-breakers 3RV1.1 3RV1.2 I n [A] I >[A] I cn [ka] Selectivity limits [ka] 1) 5SX Characteristic A SX2/5SX Characteristic B / / / / / / / / / SX2/5SX Characteristic C / / / / / / / / / / / / / / / / SX Characteristic D ) In 240/415 V, 50 Hz networks, the selectivity limits must be reduced by 10 %. I > = Tripping current. Siemens I /11

11 Selectivity MCBs/circuit-breakers Under short-circuit conditions, in acc. with IEC and selectivity is provided between DIN VDE 0660 Part 101 up to the MCBs and circuit-breakers the specified values in ka. Limit values of the MCBs/circuit-breakers selectivity in ka Downstream MCBs Upstream circuit-breakers 3RV1.3 I n [A] I >[A] I cn [ka] Selectivity limits [ka] 1) 5SX Characteristic A SX2/5SX Characteristic B / / / / / / / / / SX2/5SX Characteristic C / / / / / / / / / / / / / / / / SX Characteristic D ) In 240/415 V, 50 Hz networks, the selectivity limits must be reduced by 10 %. I > = Tripping current. 2/12 Siemens I

12 Selectivity MCBs/circuit-breakers Under short-circuit conditions, in acc. with IEC and selectivity is provided between DIN VDE 0660 Part 101 up to the MCBs and circuit-breakers the specified values in ka. Limit values of the MCBs/circuit-breakers selectivity in ka Downstream MCBs Upstream circuit-breakers 3RV1.4 I n [A] I >[A] I cn [ka] Selectivity limits [ka] 1) 5SX Characteristic A SX2/5SX Characteristic B / / / / / / / / / SX2/5SX Characteristic C / /10 6/10 6/10 6/ / /10 6/10 6/10 6/ / /10 6/10 6/10 6/ / /10 6/10 6/10 6/ / / / / / / / / / / / / SX Characteristic D SX Characteristic C / / / SX Characteristic D / / / ) In 240/415 V, 50 Hz networks, the selectivity limits must be reduced by 10 %. I > = Tripping current. Siemens I /13

13 Selectivity MCBs/circuit-breakers Under short-circuit conditions, in acc. with IEC and selectivity is provided between DIN VDE 0660 Part 101 up to the MCBs and circuit-breakers the specified values in ka. Limit values of the MCBs/circuit-breakers selectivity in ka Downstream MCBs Upstream circuit-breakers 3VF3 3VF3 Adjustable Fixed setting I n [A] I >[A] I cn [ka] Selectivity limits [ka] 1) 5SX2/5SX4 Characteristic A Characteristic B / /10 6/10 6/10 6/10 6/ /10 6/9.7 6/10 6/10 6/ / /6.6 6/10 6/10 6/10 6/ / /6.2 6/6.5 6/ / /10 6/10 6/ / / /10 6/10 6/ / / /10 6/10 6/ / / / / / / / Characteristic C /10 6/10 6/10 6/10 6/10 6/10 6/10 6/10 6/10 6/10 6/10 6/10 6/ /10 6/10 6/10 6/10 6/10 6/10 6/10 6/10 6/10 6/10 6/10 6/10 6/ /10 6/10 6/10 6/10 6/10 6/10 6/10 6/10 6/10 6/10 6/10 6/10 6/ /10 6/10 6/10 6/10 6/10 6/10 6/10 6/10 6/10 6/10 6/10 6/10 6/ / /9.5 6/10 6/10 6/10 6/ /8.2 6/6.3 6/8.2 6/8.6 6/ / /9.5 6/10 6/10 6/10 6/ /8.2 6/6.3 6/8.2 6/8.6 6/ / /9.5 6/10 6/10 6/10 6/ /8.2 6/6.3 6/8.2 6/8.6 6/ / /7.9 6/10 6/10 6/ / / /7.9 6/10 6/10 6/ / / /10 6/10 6/ / / /10 6/10 6/ / / /10 6/10 6/ / / / / / / / Characteristic D SX7 Characteristic C Characteristic D ) In 240/415 V, 50 Hz networks, the selectivity limits must be reduced by 10 %. The selectivity limits are valid for adjustable releases for the maximum value, I n = rated current. I > = Tripping current. 2/14 Siemens I

14 Selectivity MCBs/circuit-breakers Under short-circuit conditions, in acc. with IEC and selectivity is provided between DIN VDE 0660 Part 101 up to the MCBs and circuit-breakers the specified values in ka. Limit values of the MCBs/circuit-breakers selectivity in ka Downstream MCBs Upstream circuit-breakers 3VF4 3VF5 3VF6 3VF7 3VF8 3WN1 3WN6 I n [A] I >[A] I cn [ka] Selectivity limits [ka] 1) 5SX2/5SX4 Characteristic A Characteristic B /10 6/10 6/10 6/10 6/10 6/10 6/10 6/10 6/10 6/10 6/10 6/10 6/10 6/10 6/ /10 6/10 6/10 6/10 6/10 6/10 6/10 6/10 6/10 6/10 6/10 6/10 6/10 6/10 6/ /10 6/10 6/10 6/10 6/10 6/10 6/10 6/10 6/10 6/10 6/10 6/10 6/10 6/10 6/ /10 6/10 6/10 6/10 6/10 6/10 6/10 6/10 6/10 6/10 6/10 6/10 6/10 6/10 6/ /10 6/10 6/10 6/10 6/10 6/10 6/10 6/10 6/10 6/10 6/10 6/10 6/10 6/10 6/ /10 6/9.6 6/10 6/10 6/10 6/10 6/10 6/10 6/10 6/10 6/10 6/10 6/10 6/10 6/ /10 6/9.6 6/10 6/10 6/10 6/10 6/10 6/10 6/10 6/10 6/10 6/10 6/10 6/10 6/ / /10 6/10 6/10 6/10 6/10 6/10 6/10 6/ / /10 6/10 6/10 6/10 6/10 6/10 6/10 6/10 Characteristic C /10 6/10 6/10 6/10 6/10 6/10 6/10 6/10 6/10 6/10 6/10 6/10 6/10 6/10 6/ /10 6/10 6/10 6/10 6/10 6/10 6/10 6/10 6/10 6/10 6/10 6/10 6/10 6/10 6/ /10 6/10 6/10 6/10 6/10 6/10 6/10 6/10 6/10 6/10 6/10 6/10 6/10 6/10 6/ /10 6/10 6/10 6/10 6/10 6/10 6/10 6/10 6/10 6/10 6/10 6/10 6/10 6/10 6/ /10 6/10 6/10 6/10 6/10 6/10 6/10 6/10 6/10 6/10 6/10 6/10 6/10 6/10 6/ /10 6/10 6/10 6/10 6/10 6/10 6/10 6/10 6/10 6/10 6/10 6/10 6/10 6/10 6/ /10 6/10 6/10 6/10 6/10 6/10 6/10 6/10 6/10 6/10 6/10 6/10 6/10 6/10 6/ /10 6/10 6/10 6/10 6/10 6/10 6/10 6/10 6/10 6/10 6/10 6/10 6/10 6/10 6/ /10 6/10 6/10 6/10 6/10 6/10 6/10 6/10 6/10 6/10 6/10 6/10 6/10 6/10 6/ /10 6/10 6/10 6/10 6/10 6/10 6/10 6/10 6/10 6/10 6/10 6/10 6/10 6/10 6/ /10 6/10 6/10 6/10 6/10 6/10 6/10 6/10 6/10 6/10 6/10 6/10 6/10 6/10 6/ /10 6/10 6/10 6/10 6/10 6/10 6/10 6/10 6/10 6/10 6/10 6/10 6/10 6/10 6/ /10 6/8 6/9.1 6/10 6/10 6/10 6/10 6/10 6/10 6/10 6/10 6/10 6/10 6/10 6/ /10 6/8 6/9.1 6/10 6/10 6/10 6/10 6/10 6/10 6/10 6/10 6/10 6/10 6/10 6/ / /6.5 6/6.5 6/6.5 6/6.5 6/10 6/10 6/10 6/10 6/10 6/10 6/10 6/ / /6.2 6/6.2 6/6.2 6/6.3 6/10 6/10 6/10 6/10 6/10 6/10 6/10 6/10 Characteristic D SX7 Characteristic C Characteristic D /70/ 45/70/ 45/70/ 45/70/ 45/70/ 45/70/ 50/70/ 70/ 65/80/ 65/75 1) In 240/415 V, 50 Hz networks, the selectivity limits must be reduced by 10 %. The selectivity limits are valid for adjustable releases for the maximum value, I n = rated current. I > = Tripping current. Siemens I /15

15 Selectivity MCBs/MCBs In distribution networks without any fuses, MCBs provide selectivity between themselves within close limits. Limit values of the MCBs/MCBs selectivity in ka This depends on the peak current Î of the downstream MCB and on the tripping current of the upstream MCB. The following table specifies the short-circuit currents in ka up to which selectivity is provided between MCBs connected in series at 230 V AC. Downstream MCBs Upstream MCBs 5SX4 7 Characteristic C 5SX7 7 Characteristic C 5SX7 8 Characteristic D I n [A] I >[A] I cn [ka] Selectivity limits [ka] 1) 5SX2/5SX4 Characteristic B / / / / / / / / / Characteristic C / /10 6/ / /10 6/ / /10 6/ / /10 6/ / / / / / / / / / / / / /16 Siemens I

16 Back-up protection, MCBs/fuses If the level of the maximum short-circuit current flowing at the MCB location is unkown, or if the specified rated breaking capacity is exceeded, an additional protective device must be connected upstream as backup protection. This prevents Limit values of the MCBs/fuses back-up protection in ka excessive stressing of the MCB. Generally, a fuse is used for this purpose. The following table specifies the short-circuit currents in ka up to which back-up protection is guaranteed if fuses are used acc. to DIN VDE 0636 Part 21. Downstream MCBs Upstream fuses I n [A] 50 A 63 A 80 A A 125 A 160 A 5SX2/5SX4 Characteristic C No back-up protection required up to 50 ka Characteristic B/C Characteristic C Characteristic B/C Characteristic C Test circuit data: Test cycle: U p = 250 V 0 (60 ) - t - 0 (60 ), t = 3 min cos ϕ = 0.27 to 0.49 (2 trips at 60 electrical) Siemens I /17

17 Back-up protection, MCBs/circuit-breakers If MCBs are used in fuseless back-up protection in accordance with EN and distribution boards, circuitbreakers are to be provided as DIN VDE 0660 Part 101. Limit values of the MCBs/circuit-breakers back-up protection in ka The following table shows the short-circuit currents in ka up to which back-up protection is guaranteed if circuit-breakers are used. Downstream MCBs 5SX2/5SX4 Characteristic A, Characteristic B, Characteristic C, Characteristic D, Upstream circuit-breakers 3VF3 Adjustable 3VF3 Fixed setting I n [A] I >[A] I cn [ka] Back-up protection up to ka /10 No back-up protection required up to 50 ka 6 6/ / / / / / / / / / SQ2 Characteristic B, Characteristic C /18 Siemens I

18 Back-up protection, MCBs/circuit-breakers When a short circuit develops, and the upstream circuit-breakers up to the values specified in back-up protection is provided between the downstream MCB ka. Limit value of the MCBs/circuit-breakers back-up protection in ka Downstream MCBs 5SX2/5SX4 Characteristic A, Characteristic B, Characteristic C, Characteristic D 5SQ2 Characteristic B, Characteristic C Upstream circuit-breakers 3VF4 3VF5 3VF6 3VF7 3VF8 3WN1/ 3WS1 I n [A] I >[A] I cn [ka] 45/70/ 45/70/ 45/70/ 45/70/ 45/70/ 50/70/ 70/ 65- Back-up protection up to [ka] /10 No back-up protection required up to 50 ka 6 6/ / / / / / / / / / Siemens I /19

19 e Internal resistances and power losses Data is per phase (with load I n ) I n [A] Type A Type B Type C Type D 5SX2, 5SX4, 5SX5 5SX7 5SQ2 R 1 P v R 1 P v R 1 P v R 1 P v mω W mω W mω W mω W Correction factors for power losses DC and AC up to 60 Hz x 1.0 AC 200 Hz x Hz x Hz x 1.3 2/20 Siemens I

20 Personnel protection using MCBs According to DIN VDE 0 device must ensure that a fault Part 410, to provide protection with negligible impedance (i.e. against hazardous shock currents in TN supply networks, the position between an external a short circuit) at an arbitrary dimensioning of the cross sections of conductors and/or their connected exposed conductive and a protective conductor or a lengths after the protective part causes an automatic disconnection within the specified times of 0.4 s or 5 s. This requirement is met by the following condition: Z s x I a U o Z s I a U o r Impedance of the entire fault loop circuit r Current, which causes the disconnection within the specified times r Voltage to ground Maximum permissible impedance Z, of the fault loop at U o = 230 V AC to comply with the disconnection condition according to DIN VDE 0 Part 410. I n [A] Characteristic A Characteristic B Characteristic C Characteristic D 5SX, 5SQ t a 0.4 s 5 s t a 0.4 s 5 s t a 5 s 5 s t a 0.4 s 5 s Ω Ω Ω Ω Ω Ω Ω Ω For U o = 240 V AC, Z s x For U o = 127 V AC, Z s x Siemens I /21

21 Protecting luminaire circuits Maximum permissible lamp load for a 5SQ3, 5SX2, 5SX4, 5SX5 miniature circuit-breaker Max. number of fluorescent lamps when feeding fluorescent lamps L 18 W, L 36 W, L 38 W, L 58 W. I n [A] Lamp Conventional control gear Electronic control gear Single lamp Full circuit Group circuit uncomp. Parallel Single lamp Two lamps Single lamp Two lamps comp. Characteristic all all B C D B C D all all 10 L 18 W L 36 W L 38 W L 58 W L 18 W L 36 W L 38 W L 58 W L 18 W L 36 W L 38 W L 58 W L 18 W L 36 W L 38 W L 58 W L 18 W L 36 W L 38 W L 58 W L 18 W L 36 W L 38 W L 58 W Comment: MCB design: Circuit impedance: DC operation: Maximum number of low-voltage halogen lamps 12 V The specified lamp load values are valid for single-pole MCBs. When using multipole MCBs, the permissible number of lamps is reduced by 20 %. The specified lamp load values are valid, taking into account a cable impedance of 800 mω. For 400 mω the permissible values are reduced by 10 %, for 200 mω by 20 %. The values in the table are also valid for DC operation for 5SX5 MCBs in conjunction with electronic control gear. I n [A] Lamp 20 W Lamp 50 W transf. 5NZ NZ NZ NZ SX2, 5SX4 Characteristic B Characteristic C Reduction factors for MCBs for a simultaneous switch-on of an incandescent lamp load referred to the rated current of the MCB and the total operating current of the lamps Reduction factor Switching using MCBs Switching using a separate switch 5SQ3, 5SX2, 5SX4, 5SX5 Characteristic A Characteristic B Characteristic C 1 1 Characteristic D 1 1 2/22 Siemens I

22 Load capacity of MCBs with compensated and non-compensated HQ, HQI and NAV lamps (Number) Lamp rating [W] Lamp current [A] Comp. lamp current [A] Inrush [A] I n [A] Lamp rating [W] SQ3, 5SX2, 5SX4 Characteristic B Characteristic C Characteristic D SX7 Characteristic B Characteristic C / /3 4/ / /7 8/ /8 5 Characteristic D 40 79/56 44/28 22/15 13/9 11/8 4/3 5/2 3/ /70 53/35 26/19 16/11 13/10 5/3 6/3 3/ /88 69/44 34/24 20/14 17/12 7/4 8/4 4/ /112 80/56 40/31 24/18 20/16 9/6 10/5 5/3 186/ /70 51/39 31/23 26/20 11/7 12/6 7/ / /87 51/48 31/29 26/25 14/9 15/8 8/5 The different values are valid for compensated/non-compensated lamps. Siemens I /23

23 Voltage-independent, selective main miniature circuit-breakers (SHU) According to DIN VDE 0645 Further, the selective main Selective main miniature circuitbreakers are essentially based vides back-up protection up to miniature circuit-breaker pro- on the mode of operation of 25 ka for all downstream MCBs. conventional MCBs and have a In the past, sealed fuses were delayed thermal release for generally used at the metering overload protection and an location to prevent power theft. electromagnetic fast release with an impact armature for As a result of various modes of short-circuit protection. operation and therefore Further, a selectivity device is different characteristics only a included which identifies limited short-circuit selectivity whether the downstream MCB can be achieved in a cascade in the load circuit can handle of upstream fuses and downstream MCBs. This selectivity the short circuit by itself or not. For situations where the MCB depends on the difference of cannot handle the short circuit, the particular rated currents. If a the selective main miniature circuit-breaker trips. meter fuse was blown due to an overcurrent or a short circuit, the power supply company Independent of its rated service department had to be current, the selective main called-in to replace the sealed miniature circuit-breaker guarantees a selectivity with regard done by a non-specialist. fuse because this could not be to the downstream MCBs acc. to EN and DIN VDE 0641 The selective main miniature circuit-breaker, however, can be Part 11 up to their rated break- reclosed by non-specialists. ing capacity The new selective main miniature circuit-breaker offers the following advantages for the system/plant user: Improved current limiting by supporting the downstream MCB using the selective main miniature circuit-breaker System-compatibility, as, with the exception of the downstream MCB, the operating characteristics of other devices are not influenced High and reliable selectivity between the sub-distribution and meter panel Safe, fast and economical reclosure by non-specialists Reclosure is not possible as long as the cause of the short circuit has not been removed A tariff monitoring function ensures that power taken from the line is registered Isolator characteristics with contact position indication according to EN Application example Selectivity with regard to downstream MCBs up to the rated breaking capacity Selectivity with regard to upstream fuses up to A Summary of the technical data Selective main circuit-breaker Standards DIN VDE 0645 Tripping characteristic E Rated voltage V AC 230/400 Rated breaking capacity ka 25 Size acc. to DIN when mounted on mounting rails acc. to DIN EN when mounting on busbars using an adapter Insulation coordination Rated insulation voltage V AC 690 Degree of pollution 3 for overvoltage class IV Connection Individual connection or group connection using busbars Terminals Saddle terminals on both ends Cross sections On both ends Stranded, max. mm 2 70 Finely stranded, max. mm 2 50 Tripping characteristic E 2/24 Siemens I

24 DC, AC/DC In DC networks up to 60 V or 120 V, all MCBs of the N System, are suitable for single-pole and 2-pole application. The 5SX5 design is required for higher voltages. Contrary to the standard product range, the 5SX5 are equipped with additional permanent magnets in the quenching chamber to support arc suppression. For this reason, the polarity of the MCB is clearly marked and must be observed when connecting the cables and conductors. Up to max. 220 V DC battery voltage Up to max. 220 V DC battery voltage (for centergrounded battery, up to max. 440 V DC) Up to max. 440 V DC battery voltage Siemens I /25

25 Power Supply Company Program Selective Main Miniature Circuit-Breakers (SHU) 5SP3, 25 ka Features Applications Advantages U n :230/400 V, Hz can be used in supply networks up to 250/440 V AC Standards: DIN VDE 0645 Mounting depth: 91 mm As main miniature circuitbreaker in meter panels. As group miniature circuitbreaker in distribution boards. Characteristic E: Adapted to the special application conditions encountered in cascade circuit configurations between fuses and MCBs. Protects insulated cables against overcurrents Isolates loads Power drawn from the supply is registered Non-specialists can reclose the circuit Meets defined selectivity requirements with respect to upstream and downstream overcurrent protective devides Can be screwed to mounting panels Can be clipped onto busbars using an adapter Can be snapped onto mounting rails in accordance with DIN EN using the mounting plate. 2/26 Siemens I