Mitsubishi Electric C Series Handling And Maintenance

Moulded case circuit breakers, earth leakage circuit breakers, earth leakage relays & circuit protectors
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Table of Contents
MOULDED CASE CIRCUIT BREAKERS,
EARTH LEAKAGE CIRCUIT BREAKERS,
EARTH LEAKAGE RELAYS &
CIRCUIT PROTECTORS
HANDLING AND MAINTENANCE
06A

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  Summary of Contents for Mitsubishi Electric C Series

  • Page 1 MOULDED CASE CIRCUIT BREAKERS, EARTH LEAKAGE CIRCUIT BREAKERS, EARTH LEAKAGE RELAYS & CIRCUIT PROTECTORS HANDLING AND MAINTENANCE...
  • Page 2: Table Of Contents

    CONTENTS Items to be practiced without fail for safety Cautionary instructions for operation ................................1 Cautionary instructions for maintenance & inspection ............................ 2 Cautionary instructions for work ..................................3 Before using Cautionary instructions in general ..................................5 Operation ..........................................6 2.2.1 Switching operation ......................................
  • Page 3: Items To Be Practiced Without Fail For Safety

    1. Items to be practiced without fail for safety For correct operation, please go over this paper “Items to be practiced without fail for safety” beforehand. Essential items to ensure safety are stated here. Be sure to follow the cautionary instructions given ●...
  • Page 4: Cautionary Instructions For Maintenance & Inspection

    CAUTION Layman’s work is dangerous. Any electric work must be carried out by a qualified person ● (electrician). When the breaker cuts off automatically, turn it on after eliminating the cause. Otherwise, ● electrification and fire can result. If the cause is unknown, please contact us at our service station, branch offices, local offices, or ask an electrician in your country.
  • Page 5: Cautionary Instructions For Work

    1.3 Cautionary instructions for work CAUTION Any electric work must be carried out by a qualified person (electrician). ● Before wiring, turn off the upper circuit breaker and make sure of no current conducting. ● Electrification can result. Procedure 1: Upper circuit breaker (Turn OFF) Procedure 2: (With a detector, make sure of no current conducting.)
  • Page 6 CAUTION At wire connection, fasten the terminal screws with the torque stated in the instruction manual. ● Fastening with incorrect torque can cause fire. Example of front connection type fastening torque (Others are in Appendix 2.) Screw diameter Shape Terminal screw Fastening torque...
  • Page 7: Before Using

    2. Before using Besides operation, the items in this section are also applicable to work, maintenance and inspection. 2.1 Cautionary instructions in general DANGER (1) Refrain from touching the terminal unit as electrification can result. Note: Besides the terminal of the circuit breaker, the terminal unit includes the wires, bus bars, ring-type terminals, and other wiring materials.
  • Page 8: Operation

    2.2 Operation 2.2.1 Switching operation Electric power can be turned ON/OFF by moving the handle up/down. Note 1. Never apply any excessive impact to the handle. Note 2. When the extension handle is used, fix it firmly with screws. After use, remove the extension handle quickly.
  • Page 9: Trip And Reset Operation

    2.2.2 Trip and reset operation (1) For moulded-case circuit breaker 1 Tripping The moulded-case circuit breaker has an overcurrent tripping device which opens the circuit on detecting magnitude of overload current or short-circuit current, and is used for protecting electric wires and other power circuit.
  • Page 10 (2) For earth leakage circuit breaker 1 Trip Tripping of earth leakage circuit breaker includes two kinds; leak trip in which magnitude of leakage is detected for automatic tripping (open circuit), and overcurrent trip in which magnitude of overload current or short-circuit current is detected for automatic tripping. For distinction of two kinds of tripping, the leak indication button comes out at leak trip only.
  • Page 11 (3) For earth leakage relay 1 Operation When leakage is detected by the earth leakage relay, contact point output is given, the leakage indicator button comes out, or the leakage indication lamp glows. 2 Reset operation CAUTION When the leakage indication button comes out or the leakage indication lamp glows, remove the cause then reset before starting operation again.
  • Page 12: How To Set Current Rating, Trip Characteristic, Sensitive Current And Operating Time

    2.3 How to set current rating, trip characteristic, sensitive current and oper- ating time 2.3.1 Cautionary instructions for setting CAUTION Let a person having technical knowledge of electricity set the breaker. ● Before setting, turn off the upper circuit breaker, or turn off the circuit breaker to be set or trip ●...
  • Page 13 [for Group A] (1) Open the button cover using a MODEL screwdriver as illustrated at left. RE250 (2) Set operating characteristics by OVER 50/60Hz(AC only) turning the dials. TEST × × L(s) × 175 200 250A) For turning the dials for chracteristic setting,use a screwdriver as illus- trated at left.a 1 A slotted head screwdriver of...
  • Page 14: How To Set Characteristics Of Molded-Case Circuit Breakers [Electronic Overcurrent Tripping Type]

    2.3.3 How to set characteristics of molded-case circuit breakers [electronic overcurrent tripping type] ETR (Electronic trip relay) mounting circuit breaker Applicable model (NF1250-UR) Rated current Short time-delay tripping characteristic Item Rated current label Electronic type trip relay unit (with cover) Layout of setting terminals...
  • Page 15: How To Set Inverse Time-Delay Or Instantaneous Tripping Characteristics Of Circuit Breakers [Adjustable Thermal Or Magnetic Type]

    2.3.5 How to set inverse time-delay or instantaneous tripping characteristics of circuit breakers [Adjustable thermal or magnetic type] Adjustable magnetic type Applicable model NF125-SGW(RT), NF125-HGW(RT), NF160-SGW(RT), NF160-HGW(RT), NF250-SGW(RT), NF250- HGW(RT), NF630-SW, NF800-SDW, NF1000-SDW, NF1250-SDW, NF1600-SDW, NF2000-S, NF2500-S NF3200-S, NF4000-S, NV630-SW, NV1000-SB, NV1200-SB, NF-SJW, NF-HJW Inverse time-delay or instantaneous tripping characteristic Item Layout of...
  • Page 16: How To Change Rated Current, Tripping Characteristic And Leak Tripping Characteristic Series Earth Leakage Circuit Breakers (Electronic Overcurrent Tripping Type)

    2.3.7 How to change rated current, tripping characteristic and leak tripping characteristic of earth leakage circuit breakers (electronic overcurrent tripping type) NV100-SEP, NV100-HEP NV250-SEW, NV250-HEW Seal attaching position OVER LED (Red) SEALED PAL LED (Yellow) Leakage indicator 70% LED (Green) (comes out at leak tripping) Sensitivity current setting dial Operation time setting dial...
  • Page 17 NV400-SEW, NV400-HEW, NV400-REW NV630-SEW, NV630-HEW NV800-SEW, NV800-HEW Sensitivity current setting dial Operation time setting dial (for time delay type) Rated current label Leakage indicator (comes out at leak tripping) Test button Trip button OVER LED (Red) (PTT) PAL LED (Yellow) 70% LED (Green) Transparent cover Replacement label...
  • Page 18: How To Switch Voltage, Sensitivity Current And Operating Time Of Earth-Leakage Relay

    2.3.8 How to switch voltage, sensitivity current and operating time of earth-leakage relay Earth leakage relay ZSA, ZHA, ZLA 240V Sensitivity current selector 415V Sensitivity current Operating time selector selector (time-delay type) 0.2A Change-over switch 0.5A 120V Operating time selector 240V 415V (time-delay type)
  • Page 19: Installation

    3. Installation 3.1 Notice for selection For selection, refer to the catalog, technical data, specifications and other technical materials. For any question concerning the selection method, please enquire us. We are not responsible for any failure and damage caused by wrong selection. 3.2 Normal service conditions Our circuit breakers of the standard specifications are to be used in the following standard conditions.
  • Page 20: Non-Standard Conditions

    3.3 Non-standard conditions When operated under different conditions from the normal service conditions, it is necessary to take the following measures against the operating conditions. Even with such measures taken, however, service life may become shorter in some cases. Applicable model Circuit breaker for Special environment Specifications...
  • Page 21: Inspection At Arrival

    3.4 Inspection at arrival (1) Make sure that the packing case is free from any abnormality such as breaking and wetting. (2) Referring to the name plate, make sure that the delivered breaker is in conformity with your order. (3) Check for the parts contained in the same package. 1 Mounting screws 2 Terminal screws 3 Insulation barriers (The barrier is contained in the same package for some models, but not for other...
  • Page 22: Installation And Connection

    3.6 Installation and connection 3.6.1 General CAUTION • Let a qualified person (electrician) carry out the electrical work. • Before wiring, turn the upper circuit breaker to OFF. Make sure that no power is supplied to prevent that the electrification can occur. 3.6.2 Installation CAUTION Install the breaker in normal environment.
  • Page 23: Connection

    Prevent the ingress of Avoid strong electro Never use thinner, detergent, and Do not adhere gum tape water into the enclosure. other chemicals for cleaning. on the name plate. magnetic field. When a transceiver is used, keep It is likely to make letters on the The name plate may come off.
  • Page 24: Mounting Direction

    3.6.4 Mounting direction (1) For the following models, pay attention to attaching position as overcurrent tripping is of fHydraulic- magnetic type and the tripping characteristic varies depending on mounting position. It is recom- mendable to use them attached vertically. Type Moulded-case circuit NF30-CS, NF50-SS (1P), NF63-CW breaker...
  • Page 25: Distances Between Circuit Breaker And Earthed Metal Parts

    3.6.5 Distances between circuit breaker and earthed metal parts When short circuit current is cut off, ionized gas goes out of the exhaust port at the power source side of the circuit breaker. At the power source side of the circuit breaker, provide the insulation distance shown in the table so that the outgoing gas may not be bothered.
  • Page 26: Current-Carrying Capacity And Operating Temperature

    3.6.6 Current-carrying capacity and operating temperature (1) Operating current vs. ambient temperature Rated current of circuit breakers is adjusted for the rated ambient temperature. This is because circuit breakers are often installed in a casing as a switchboard or a control board, and temperature of the installed place of the breaker becomes higher than ambient temperature of the wires.
  • Page 27 1 Cautionary instructions for using heat resistive wire For using insulated wires of higher heat resistance than that of 600 V PVC insulated wire (allowable temperature 60°C), it is necessary to take the following points into consideration. For circuit breakers, size of test wire is stipulated by each test current in IEC60947-1 If size of connection wire is thinner than the test wire size, temperature of the breaker terminals increases and overcurrent tripping operation characteristic may change in some cases.
  • Page 28: Breaker Arrangements

    3.6.7 Breaker arrangements (1) Connection of no-fuse breaker 1 Inverse connection The illustration (a) is the standard connecting arrangement of line and load of the breaker termi- nals. Except for the models which accept inverse connection, connection of (b) may lower breaking performance and inverse connection isn’t advisable.
  • Page 29 (2) Connection of earth leakage circuit breaker CAUTION 1 Connect to a power source suitable for the rating of the circuit breaker. Otherwise, malfunc- tion and failure can result. Application of overvoltage outside the applicable voltage range can cause burning as the earth leakage circuit breaker incorporates electronic circuits.
  • Page 30 (3) Connection of Molded-case circuit breaker with earth leakage current CAUTION 1 Connect to a power source suitable for the rating of the circuit breaker. Otherwise, mal- function and failure can result. Application of overvoltage outside the applicable voltage range can cause burning as the earth leakage circuit breaker incorporates electronic circuits.
  • Page 31 (4) Connection of MDU breaker 1 Connections and installation CAUTION • Do not connect in reverse about line side and load side. • Do not pull the cable which connects MDU and the circuit breaker over 15N. The cable may come off. •...
  • Page 32 CAUTION • The size of wiring MDU is shown as below. Single core Twisted core In case of single connection 0.45-1.2mm 0.14-1.5mm In case of double connection 0.45-0.8mm 0.14-75mm • Tighten the terminal screws with following tightening torque. Tightening torque 0.5 - 0.6 N·m Tool minus head screw driver Bit size Thickness 0.6mm Width 3.5mm...
  • Page 33 Condition 2: (Power line and grounded line) (i) Connect FG terminal of MDU to PE terminal of MDU (panel) holder plate. Make the earthing point (to be grounded to the earth) near MDU. PE terminal shall be grounded to this point with as short wire as possible. PE terminal effects to reduce the noise of MDU and to shut down the external noise.
  • Page 34: Instruction For Connections

    3.6.8 Instruction for connections CAUTION Use the applicable connection parts for breaker. Otherwise it may result in fire. (1) Front connection 1 Mounting Mount directly using the mount hole. Mount plate Wood screw • Mount screws for steel plate and for wood plate (a part of NV models) are attached. For dimension, refer to Appendix 1. Note) In some cities, mounting onto wood board is limited by fire defense code and others.
  • Page 35 Clamp connection When connected directly to a terminal, insert the solid or stranded wire ● straight, then fasten the terminal screws. Ring-type terminals and bars can also be connected. For stranded wires, divided the strands for insertion, then fasten. Re- ●...
  • Page 36 4Terminal cover This is used to avoid exposure of charged parts. Different kinds are prepared for topper each application such as large size terminal cover (TC-L), small size terminal projection cover (TC-S), transparent terminal cover (TTC), Rear terminal cover (BTC), and plug-in terminal cover (PTC).
  • Page 37 (2) Rear connection Rear connection type is for wiring from back side of the Stud set bolt, Circuit breaker set screw Bolt A panel and terminal connection and bar connection are End plate applicable. Rear studs (with insulation pipe or insulation base) are offered separately.
  • Page 38 Assembling procedure (C) 2. Installing the stud in the breaker NF125-SGW, NF125-HGW Stud bolt (M6) torque Be sure the plate is Model to NF160-SGW, NF160-HGW : 7.8 ~ 11.7N·m oriented correctly. NF250-SGW, NF250-HGW Circuit Wipe this surface clean. assembled NF125-RGW, NF125-UGW breaker NF250-RGW, NF250-UGW Stud...
  • Page 39 1Screw stud connection Generally, about 20kg power is generated by arm. So, tightening torque comes to m by grip-ping illustrated • position. • 200N (20kg) Assembling procedure (A) Tightening torque for screw stud NF30-CS, MB30-CS, NV30-CS NF32-SW, NF63-CW, NF63-SW, NF63-HW Model to be Tightening torque N·m MB30-SW, MB50-CW, MB50-SW...
  • Page 40 (3) Plug-in type Circuit breaker Bolt A Plug Panel ● Assembling procedure 1. Attach the plug-in terminal Plug-in Panel block having the stud onto terminal block the panel or the angle. Stud If the plug-in terminal Example of composition of plug-in type block is separate type, Plug-in Conductor connection...
  • Page 41 types for NF125-SGW, NF125-HGW, NF160-SGW, NF160-HGW, ≦23 NF250-SGW, NF250-HGW φ8.5 (M8 × 25) (M8 × 25) ● Assembling M8 × 25 9.5〜14 N・m M6 × 25 3.2〜4.8 N·m CUT OFF M5 × 12 Coating plate Note:In this connection can not do the fixation on rear plate. 2〜3 N·m Note:The M4 × 73 screws are packed           with Breaker. M4 × 73 4〜6 N·m 1.5〜2 N·m DUST...
  • Page 42 (5) Earth leakage relay 1Mounting 1. Mount the earth leakage relay and the ZCT unit separately. Refer to the catalog for mounting dimension. 2. With the relay of interchangeable type, the relay unit and the ZCT unit can be combined freely. For the relay of combination type, be sure to combine the relay unit and Conductor Keep off at...
  • Page 43: Instruction For Accessories

    3.6.9 Instruction for accessories (1) Internal accessories The following devices are installed into the circuit breakers. For the accessories with lead wires, allow at least 8 mm spacing when circuit breakers are installed side by side. Alarm switch Earth leakage alarm switch The switch for electrically indicat- This switch is for electrically indi- cate tripping of the circuit break-...
  • Page 44 (2) AL (Alarm switch), AX (Auxiliary switch) ● AL (Alarm switch) is for indicating trip state of the circuit breakers electrically. ● AX (Auxiliary switch) is for indicating ON/OFF state of the circuit breakers electrically. Operation of AL switch AL • AX Rating of switch State of circuit breaker Contact condition of AL switch...
  • Page 45 (3) SHT (Shunt trip) ■ The device to trip circuit breakers electrically from a remote position. ■ Allowable operating voltage range is 70 to 110% of the rated voltage. ■ Coil rating (Standard) Input VA (Note 1) Voltage (Note 3) Operating time Type designation of circuit breakers Cut off switch...
  • Page 46 (4) UVT (Under voltage trip) (a) This device make it possilble to turn ON the circuit breaker after resetting manually when supply voltage is recovered at least to 85% after dropping to 70 to 35% or lower and tripping the breaker.
  • Page 47 (b) NF400-CW to NF1600-SEW, NF100-SEP·HEP A UVT mechanical unit is incorporated in the circuit breaker, and a UVT voltage-control module is attached outside. Lowered voltage is detected by the UVT voltage-control module, and the UVT mechanical unit functions to trip. Some are so composed to trip even when the handle of the circuit breaker is at OFF state but the coil of the UVT mechanical unit isn’t energized, while others are composed for no tripping under this state.
  • Page 48 (5) Cassette accessories 130~250 A frames The cassette accessories, AL, AX, AL+AX, SHT, and UVT can be installed to the following models by each user. Type name of accessories (indicated by the attached name plate) Applicable models Mounting pole AL+AX UVTN or UVTS SHTA240-05SRUR SHTA480-05SRUR...
  • Page 49 2400~800A frames ● The cassette accessories, AL, AX, AL+AX, and SHT can be installed to the following models by each user. Type name of accessories (Indicated by the attached label) Applicable models Number of pole Mounting pole AL+AX AX-4SW SHT-4SW NF400-CW/SW/SEW/HEW/REW/UEW AX-4SWRS 2, 3...
  • Page 50 How to attach cassette accessories CAUTION • For mounting and dismounting the cassette accessories, be sure to drop voltage of the circuit breaker and the accessories to zero as electrification can result. Burning can take place should the circuit breaker operation for breaking. •...
  • Page 51 4Push the accessory into the circuit breaker to the point • Don’t mount at ON, OFF position. The accessory may fail normal operation or where click sound is heard. may be broken. ➁ ➀ click sound • With lead wires •...
  • Page 52 (6) EAL (Earth leakage alarm switch) This switch is for electrically indicating tripped state of an earth leakage circuit breaker at a ground fault. Operation of EAL switch Rating of EAL (400A frame and above) Condition of Contact condition of EAL switch Microswitch Current A Current A...
  • Page 53 (7) TBM (Test button module) 1 This module is used for testing earth leakage circuit breaker remotely while applying voltage. For time lag type, keep applying voltage for more than two seconds. 2 The voltage application system is insulated from the main circuit and SHT of MCCB can be used commonly with the control sequence.
  • Page 54 (8) MG (Insulation switch) This switch is attached for insulation resistance measurement between rihght and left poles of the models to which control power is supplied through the right and the left poles, such as earth leakage circuit breaker. Operation of insulation switch Connecting a switch interlocked with the handle to one con- Condition of circuit...
  • Page 55: External Accessories

    3.6.10 External accessories (1) Electric operation device 1 Spring-charged type (1) • Electric operation : When ON switch is turned off, a relay drives the motor to reset the latch mecha- nism, instantaneously turning the breaker ON with the accumulated force of the input spring.
  • Page 56 Caution on manual operation [Turning ON] (i) Shift MANU/AUTO selector switch to MANU. When MANU has been selected, the electric operation circuit will be automatically open. (ii) Press ON button. The latch mechanism is disengaged and the accumulated force of the input spring turns the breaker ON.
  • Page 57 Caution on OPEN (trip) button operation (i) Shift MANU/AUTO selector switch to MANU. When MANU has been selected, the electric operation circuit will be automatically open. (ii) Press OPEN (trip) button and the breaker trips. The OPEN (trip) button operating load is approx. 5 N.
  • Page 58 (a) How to install The users who purchased a single electric operation unit for 50·100·125AF are requested to take the following procedure before installing the electric operation unit on the breaker: <<50·100·125AF>> (1) For the no-fuse breaker, untighten the breaker cover screw and remove the part shown in Fig.1 with nippers then tighten the breaker cover screw again.
  • Page 59 Operation circuit terminal cover (standard accessory) Operation circuit terminal Power supply module block (M3.5 thread) Power supply module setscrew P1 P2 S1 S2 S4 OFF lock plate Breaker status ON button Not indicated for the 250AF series indicator hole units except the NF250-HGW. (ON/OFF/TRIP) MANUAL/AUTO selector switch...
  • Page 60 Cover setscrew Indicating plate hole Indicating plate Fig. 1 Fig. 2 Remove the tape separator. Fix block on the rear side of cover. The block prevents the plate Direction for the plate. from bursting out of cover. Install the indicating plate. Detail of installed the indicating plate. Fig. 5 Panel Power supply module...
  • Page 61 (i) For the Front and Rear connection type (1) Untighten the power supply module setscrew to remove the power supply module from the electric operation unit. (2) Turn the breaker OFF (Fig. 6). (3) Set the electric operation unit to "Charge" (Fig. 7) (or "OFF"...
  • Page 62 (b) Operation circuit connection (i) Connect the operation power supply to the operation power supply terminals (P1 and P2). There is no polarity. (ii) Connect ON switch and OFF switch to the operation switch terminals (S1, S2 and S4). For the operation switches, use the micro-loading switches (with approx.
  • Page 63 3 Motor-operated type (2) • Electrical Operation : The circuit-breaker is turned ON/OFF (reset) converting the forward and re- verse rotation of motor into rectilinear motion by ball screw. • Manual Operation : Manual operation handle is manipulated directly toward On or Off side of the circuit- breaker.
  • Page 64 (b) Mounting (i) Front-connection/Rear-connection (Other than the U-series). (i)-1 Sequential order for mounting the electrical operation type MCCB a) Detach the four cover mount screws (A) to remove the cover. Frame b) Fix the electric operation type MCCB on the panel using four MCCB Cover Trip mount screws (B).
  • Page 65 (iii)-2 NF400-UEW(4P), NF800-UEW Cover a) Detach the four cover mount screws (A) to remove the cover. b) Fasten the electric operation type circuit-breaker using the four breaker mount screws (B). Frame c) Connect electric operation unit to the terminal of the operational (D) Flash circuit.
  • Page 66 4 Spring-charged type (2) • Electrical Operation : When the ON operation switch is closed, the closing coil is excited, latch mechanism is released and the closing spring will turn on the circuit-breaker instantaneously. If the OFF operation switch is closed, the relay will come into function to start the motor. If, under these conditions, the circuit-breaker is turned OFF (reset), the closing spring will be charged instantaneously.
  • Page 67 (iv) In case when the main circuit is to be opened in emergency: If the main circuit is to be opened in emergency by manual operation, the circuit-breaker shall be made to trip depressing the trip button. (v) OFF lock plate If the electric operation unit is locked with a padlock with the OFF lock plate drawn out, it cannot be operated anymore electrically nor mechani- cally.
  • Page 68 (iv) Mount the electric operation unit on the circuit-breaker. Attaching screws are four M6 screws, The electric op- eration unit has been so designed that it can be provi- sionally supported by hook pin when it is to be fastened with screws.
  • Page 69 (2) Lock cover (LC) The lock cover is a plug-in type handle mechanism that can prohibit operation readily without applying any lock. A “Warning Tag” can be attached to it. One can safely use this mechanism since it may trip with its handle locked at ON position if any overcurrent flows.
  • Page 70 (3) Handle lock (HLN, HLF or HL-S) The handle locks is a device that lock ON or OFF the handle of the circuit-breaker. Users can safely use their lock because the circuit-breaker trips when an overcurrent flows therethrough even if the handle is locked into ON position. There are two types of locks: HLN and HLF which are used as mounted on the handle and HL-S which is used as fixed on the cover of the circuit-breaker.
  • Page 71 (4) Extension handle This handle makes easy the opening/closing operation of the circuit- breaker. Note 1. The extension handle, if used, shall be firmly fixed into the main handle. Note 2. The extension handle should be detached from the main promptly afteruse, because if attached to the main the auxiliary Auxiliary handle may give the internal mechanism a severe shock to reduce its...
  • Page 72 Attention (i) Never fail to remove the extension handle when the opening/closing operation is over or when UVT trip button and/or ELCB test button are operated or tripped. Otherwise it may give the in- ternal mechanism a severe shock or reduce its service life or may get into the air when the circuit- breaker trips.
  • Page 73 3 V type handle (a) Assembly ● 125 and 250 A frames ● 400, 630 and 800 A frames Breaker Joint plate Joint Breaker Square shaft Shaft Indicator Key plate Indicator plate plate Bushing Handle Handle Lock plate Lock plate (b) Shaft cutting 400, 630 and 800 A frames ●...
  • Page 74 (f) Caution Mount the external handle under OFF state. Be careful that the shaft pin rotate when the breaker is tripped under opening the door. The door cannot be closed in trip position. Reset operation under opening the door, rotate the square shaft unticlockwise by spanner or mon- key wrench.
  • Page 75: Maintenance And Inspection

    4. Maintenance and inspection CAUTION Any maintenance/inspection shall be performed by the personnel having expertise concerned. ● Note that there exists the risk of electrical shock. Any maintenance/inspection shall be performed after cutting off the master circuit-breaker ● and making sure that there is no current flowing. Note that there exists the risk of electrical shock.
  • Page 76 Voltage application time: 1 min. Attention Main circuit Auxiliary or control circuit (1)Voltage of the withstand voltage test Rated Test voltage Rated insulation Test voltage insulation (AC effective voltage of (AC effective The withstand voltage test shall be performed in voltage value) operational circuit...
  • Page 77 (3) Overcurrent trip test (1) NF125-SGW (RE), NF125-HGW (RE) NF160-SGW (RE), NF160-HGW (RE) NF250-SGW (RE), NF250-HGW (RE) NF400-SEW, NF400-HEW, NF400-REW, NF400-UEW, NF400-ZEW NF630-SEW, NF630-HEW, NF630-REW, NF630-ZEW NF800-CEW, NF800-SEW, NF800-HEW, NF800-REW, NF800-UEW, NF800-ZEW NV250-SEW, NV250-HEW NV400-SEW, NV400-HEW, NV400-REW NV630-SEW, NV630-HEW NV800-SEW, NV800-HEW The test shall be conducted only in the following test circuits: Use the optional breaker tester “Y-250”...
  • Page 78 3 LTD and pre-alarm operating time can be checked by applying a current equivalent to 200% of the current setting Ir. If however any current exceeding the current setting Ir is applied before this test, the operating time reduces. Therefore the first measurement will be invalid in that case.
  • Page 79: Periodical Inspection

    4.2 Periodical inspection The inspection shall be worked out once one month after the commencement of the use and Yardstick for inspection periodicity then periodically in terms of the environmental 1 Clean and dry environment Once every 2 to 3 years conditions in order that any trouble may be Environment not exposed to severe Once a year...
  • Page 80: Yardstick Service Life

    4.4 Yardstick service life The maintenance and inspection shall be brought into practice depending on the environment where the circuit-breaker is installed. The longevity of the circuit-breaker cannot be decided only in terms of the year of use. Though the service life requires some diagnosis by some experts, the yardstick of longevity may be as follows: Yardstick for service life Size of circuit-...
  • Page 81: Troubleshooting

    5. Troubleshooting 5.1 Troubleshooting for circuit-breaker proper (MCCB/ELCB) Trouble Cause Countermeasure Foreign matter in switching mechanism Foreign matters to be removed Closing impossible No resetting To be reset once again Resetting impossible See below (*) See below Incessant use of voltage trip operation To be replaced with new one, Voltage trip to be replaced by electric operation Wear due to trip endurance End of service life...
  • Page 82: Troubleshooting For Leakage Operation Portion

    5.2 Troubleshooting for leakage operation portion Trouble Cause Countermeasure Operates simultaneously Too long a wire and too large a ground electrostatic Rated sensitivity current to be changed, or with closing (such operation capacity causes the leak current to flow ELCB to be installed near load Trouble- of leakage mechanism as some...
  • Page 83: Analysis Of Unnecessary Operation

    5.4 Analysis of unnecessary operation Operation of ELCB by the causes on purpose, leak current, electrification, ground fault etc., is normal, while operation by other causes such as surge and induction is unnecessary (called stray operation or nuisance trip). It seems that quite a number of users have the preconception that earth leakage circuit breakers are troublesome as they operate unreasonably.
  • Page 84 (4) Operation by surge To surge by secondary transfer of inductive light- ELCB 1.2×50µS ening of wires, non-operation test by lightening impulse is set forth in JIS C-8371, and surge re- sistivity is ensured. Circuit of the lightening im- pulse non-operation test is shown at right. Almost all NVs of Mitsubishi are provided with a DPDC surge discrimination circuit for judging leak Lightening impulse...
  • Page 85 (7) Operation by wrong wire connection Failure in passing the neutral wire through the ZCT for the lines of single phase 3-wire or 3 phase 4- wire is a simple mistake. In this case, the ELCB is operated by single phase load current. Load Wrong wire connection of 3 phase 4-wire line On the other hand, the common earth wire shall...
  • Page 86 (12) Operation by carrier phone unit Malfunctions of the ELCB can result in some cases when attached to a line provided with a carrier phone, which enables calls through the power line. Since the carrier phone forcefully gives high frequency signals (normally 50kHz to 400kHz) between the line and the ground, the ELCB detects the high frequency signals as if they are leak current and leads to malfunction.
  • Page 87: After-Sales Service

    6. After-sales service 6.1 Countermeasures to be taken in case of anomaly Should any anomaly arise while the circuit-breaker is operating, take the following countermeasures: CAUTION Use to be prohibited under abnormal conditions: ● Continuing to use the circuit-breaker under abnormal conditions may lead to some acci- dents.
  • Page 88: Appendix 1 Breaker Mounting Screws

    APPENDIX 1 Breaker mounting screws ■ NFB Wood screw (round Required quantity per unit Depth Front-connection Rear-connection Plug-in (drawout) Type wood screw)for Front- ries of hole connection 4.1 ✕ 25 M4 ✕ 0.7 ✕ 20 M4 ✕ 0.7 ✕ 20 NF30-CS, MB30-CS —...
  • Page 89: Appendix 2 Standard Tightening Torque For Connections

    APPENDIX 2 Standard tightening torque for connections Rear connection, Flush Drawout Screw A Nut C Nut C Screw F Bolt Stud Screw A Bolt stud Bar stud Bolt stud Insulation Connection Connection base Insulation ring Connection conductor conductor conductor Fig.2 Fig.1 (NV100-HB) Fig.7...
  • Page 90: Appendix 3 Operating Force Of Handle

    APPENDIX 3 Operating force of handle The numerical values below represent the measurements resulting from the handle as pulled horizontally (arrowed direction). B size gives the dimen- sions without those of auxiliary handle. Operational force of handle, N · m Dimensions (mm) Type Poles...
  • Page 91: Appendix 4 Service Network

    Geminivej 32, DK-2670 Greve, Denmark. P.O. BOX: 165-11516, Maglis El-Shaab + 20-2-7961337 Egypt CAIRO ELECTRICAL GROUP Cairo-Egypt. Germany Mitsubishi Electric Europe B.V. German Branch. Gothaer Strasse 8, 40880 Ratingen, Germany. + 49-(0)2102-4860 52, Arkadias + 30-1-57-81-599-699 Greece Drepanias Antonios S.A.
  • Page 92 MEMO...
  • Page 93 MEMO...
  • Page 94 MOULDED CASE CIRCUIT BREAKERS, EARTH LEAKAGE CIRCUIT BREAKERS, EARTH LEAKAGE RELAYS & CIRCUIT PROTECTORS Safety Tips : Be sure to read the instruction manual fully befofe using this product. FACTORY AUTOMATION SYSTEM: TOKYO BUILDING, 2-7-3 MARUNOUCHI, CHIYODA-KU, TOKYO 100-8310, JAPAN Revised publication, effective Mar.

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