SE-502 MANUAL GROUND-FAULT GROUND
Contents
1. Littelfuse STARTCO 3714 Kinnear Place Saskatoon Saskatchewan Canada 57 0A6 SE 502 MANUAL Ph 306 373 5505 306 374 2245 www startco ca GROUND FAULT GROUND CONTINUITY DETECTOR April 25 2012 REVISION 0 LITTELFUSE STARTCO GROUND FAULT TRIP PRESENT CLEAR OPEN NEUTRAL DIAGNOSTIC ERROR POWER FA Littelfuse GROUND FAULT GROUND CONTINUITY DETECTOR GROUND CONTINUITY TRIP Copyright 2012 by Littelfuse Startco All rights reserved Publication SE 502 M Document S95 C502 00000 Printed in Canada SE 502 Littelfuse Rages STARTCO SE 502 Ground Fault Ground Continuity Detector Rev 0 This page left intentionally blank Pub SE 502 M April 25 2012 P4 Littelfuse oe STARTCO SE 502 Ground Fault Ground Continuity Detector Rev 0 PREFACE Current flowing to ground has only two paths it can flow to ground through a ground fault and it can flow to ground through distributed capacitance Current flowing to ground through distributed capacitance can cause sympathetic tripping during a ground fault and its unbalance can cause tripping during normal operation These trips are not to be confused with false trips that occur when poorly designed ground fault detection systems respond to anything other than zero sequence current at the fundamental frequency of these trips are nuisance trips If nuisance trips are frequent enough to interfere with prod2. malfunction Littelfuse Page v STARTCO SE 502 Ground Fault Ground Continuity Detector Rev 0 This page intentionally left blank Pub SE 502 M April 25 2012 P4 Littelfuse ae tagel STARTCO SE 502 Ground Fault Ground Continuity Detector Rev 0 1 GENERAL 2 OPERATION The SE 502 is a microprocessor based ground fault and ground continuity detector that provides Class A GFCI trip levels and trip times for a three phase 120 208 V portable generator All operating conditions are clearly indicated and Form C contacts are provided for the main breaker s trip circuit Two Form C contacts are also provided for remote ground fault and ground continuity indication All specifications apply over an industrial temperature range at high humidity and the SE 502 is designed to meet the IEEE surge withstand capability tests oscillatory and fast transient for protective relays and relay systems The SE 502 s ground fault circuit has an internal neutral grounding resistor NGR that limits ground fault current to 100 mA This eliminates the flash hazard and susceptibility to nuisance tripping is reduced as trip times less than 100 ms are not required to achieve Class A GFCI performance The SE 502 impresses a small dc voltage on the neutral of the generator to measure the resistance to ground of the entire system connected to the load side of the generator s main breaker If resistance to ground is less than 24 KQ 5 mA 120 V t
3. permit the use of resistance grounding with line to neutral loads Canadian Electrical Code Section 10 1102 specifically allows and lists provisions for line to neutral loads on resistance grounded systems Wid Littelfuse Page iii STARTCO SE 502 Ground Fault Ground Continuity Detector Rev 0 This page left intentionally blank Pub SE 502 M April 25 2012 Littelfuse STARTCO 2 2 2 3 TABLE OF CONTENTS PROLACE 1 Operation Configuration Switch Settings 2 1 1 Relay Operating 2 1 2 Ground Continuity Front Panel Indication 221 Ground 2 2 2 Diagnostic Pub SE 502 M April 25 2012 SE 502 Ground Fault Ground Continuity Detector Page iv Rev 0 LIST OF FIGURES PAGE 1 SE 502 Outline and Mounting 1 3 2 8 502 Typical 4 DISCLAIMER Specifications are subject to change without notice Littelfuse Startco is not liable for contingent consequential damages or for expenses sustained as a result of incorrect application incorrect adjustment or a
4. IONS IN MILLIMETRES INCHES CQENSETY RESET 2 MOUNTING SCREWS M4 x 13 OR 8 32 x 0 50 6 OVERALL DIMENSION WHEN MOUNTED ON DIN EN50022 35 mm 75 mmTOP HAT RAIL 113 0 NOTE 3 4 45 _ LITTELFUSE STARTCO 7 GROUND FAULT GROUND CONTINUITY DETECTOR SE 502 GROUND FAULT TRIP GROUND CONTINUITY OPEN NEUTRAL DIAGNOSTIC PRESENT DAON CLEAR POWER FA Littelfuse 16 17 18 19 20 21 22 23 24 25 26 27 28 2930 GROUND D FAULT CONTINUITY Le 2 1 N 1 MOUNTING DETAIL FIGURE 1 SE 502 Outline and Mounting Details Pub SE 502 M April 25 2012 P4 Littelfuse a es STARTCO SE 502 Ground Fault Ground Continuity Detector Rev 0 GENERATOR 120 208 V 1 20 UV ENERGIZED XN GF INDICATOR N 7 N GC INDICATOR REMOTE NEUTRAL R me SENSE 1 ai 5 GROUNDO NEUTRAL Ce 1 502 118 CONTINUITY E SENSE 1 GROUND ELECTRODE SENSE LEAD TO ALTERNATE GROUND FIGURE 2 SE 502 Typical Application Pub SE 502 M April 25 2012
5. andated for small single phase loads In spite of the fact that GFCI levels were never intended for three phase systems attempts are often made to achieve these trip levels on equipment such as submersible pumps A special problem exists with respect to portable generators Most electrical codes require portable generators to be grounded with ground rods or electrodes however location and conditions can make this difficult to achieve This problem has been recognized by Ontario Hydro Electrical Inspection Metro Territory On September 28 1998 Ontario Hydro issued guidelines to Inspectors and the entertainment industry to assist them to achieve safe electrical installations These guidelines allow a ground other than an approved electrode to be used if it is verified with a ground proving device Also in 1997 the Construction Safety Association of Ontario CSAO published a report titled The Use of Ground Fault Circuit Interrupters on Portable Generators This report outlines conditions under which personnel protection is not achieved with The SE 502 Ground Fault Ground Continuity Detector provides a solution to the problem of personnel protection for portable generators It also has application in utilization systems requiring a lockout that will not allow a faulted system Pub SE 502 M April 25 2012 to be energized Consider the following Since capacitance to ground causes nuisance tripping levels in co
6. annunciation relay is energized 2 2 2 GROUND CONTINUITY The red LED labeled TRIP indicates a ground continuity circuit trip A trip will remain latched until the ground electrode loop resistance is less than 25 and a reset is performed See Section 2 3 The yellow LED labeled NO indicates an unacceptable ground electrode loop resistance The ground continuity annunciation relay is not energized and ground continuity trip will not reset The green LED labeled YES indicates an acceptable ground electrode loop resistance The ground continuity annunciation relay is energized and a ground continuity trip can be reset Page 2 SE 502 Ground Fault Ground Continuity Detector Rev 0 2 2 3 POWER INGR 1440 Q The green LED labeled POWER indicates presence of the Thermally Protected supply voltage Ground Continuity Circuit 2 2 4 OPEN NEUTRAL Continuity Indication lt 250 The red LED labeled OPEN NEUTRAL indicates an Trip Resistance gt 500 open neutral trip open neutral trip is caused by Trip 1 0 15 lack of continuity between NEUTRAL SENSE terminal 8 and NEUTRAL terminals 1 and 2 See Fig 2 Neutral Sense Circuit Some lamp ballast ground tests may cause a nuisance Tip Times 5 0 15 open neutral trip RESET Front Panel Switch and 2 2 5 DIAGNOSTIC ERROR Remote N O Momentary The red LED labeled DIAGNOSTIC ERROR
7. he SE 502 will trip the main breaker in less than Class A times and it will not allow the main breaker to close until resistance to ground is greater than 24 LED indication and a relay for remote indication of a ground fault are diagnostic tools that allow a ground fault to be easily located on a de energized system When a faulted section is disconnected from the system by breakers or by couplers the SE 502 will indicate that no fault exists and it will allow the main breaker to be set The SE 502 is designed to be used in a tripping system If a system remains energized with a ground fault the SE 502 will reduce NGR current if NGR temperature approaches its thermal limit The SE 502 s ground continuity circuit uses a sense lead connected to a probable ground to confirm that the electrode chosen for the system ground is an acceptable ground Ground electrode loop resistance must be less than 25 Q for the circuit to confirm the ground LED indication and a relay for remote indication allow probable grounds to be easily tested for acceptability If the ground continuity trip switch is in the ENABLE position the resistance of the ground electrode loop will be continuously monitored and it will trip the main breaker if the loop resistance increases above 50 The SE 502 neutral continuity circuit uses a sense lead connected to the system neutral to continuously monitor continuity of the neutral circuit A loss of continuity initiates a
8. indicates a Contact diagnostic error trip Press RESET or cycle supply voltage If problem persists contact Littelfuse Startco Output Relays A flashing LED indicates that the NGR has reached its Contact Rating 8 A Resistive thermal limit Clear the ground fault allow the SE 502 to 250 Vac 30 Vdc cool and press RESET Contact Configuration Form C Trip Relay 2 3 RESET Operating Fail Safe or Non Fail Safe When a trip occurs the trip remains latched until the Annunciation Relays RESET switch is pressed the remote reset terminals 12 and Operating Fail Safe 13 are shorted or the supply voltage is cycled The reset circuit responds only to a momentary closure so that a Environment jammed or shorted switch will not maintain a reset signal Operating Temperature 40 C to 70 C Storage Temperature 55 C to 80 C 3 INSTALLATION Humidity 85 Non Condensing An SE 502 can be surface or DIN rail mounted See Surge 1 37 90 1 1989 Fig 1 Oscillatory and Fast Connect the SE 502 as shown in Fig 2 Ensure that the Transient generator neutral is not internally grounded Remove the connection to terminal 18 for dielectric strength testing all inputs and outputs have ANSI IEEE C37 90 surge protection circuits that conduct above 300 Vac 4 TECHNICAL SPECIFICATIONS Su
9. nventional systems to be larger than Class A GFCI trip levels a technique that ignores capacitive current to ground is required if Class A GFCI trip levels are to be achieved without nuisance tripping The SE 502 accomplishes this by using a dc signal to measure resistance to ground of the entire system The disadvantage of this technique is that it will not detect current through a person contacting a phase conductor with a series capacitor We are faced with a conundrum t is impossible to build a protective relay that both ignores and detects capacitive current Since the probability of contact through a capacitor is much smaller than the probability of direct or resistive contact the SE 502 reduces risk to personnel by providing protection in the most probable occurrences that could result in electrocution It is common misconception that conventional limit ground fault current to 5 or 30 mA They do not Ground fault current is limited only by the system impedance until the trip occurs The SE 502 limits ground fault current to a maximum value of 100 mA A very positive consequence of the 100 mA limit is that the arc flash hazard on the first ground fault is eliminated The SE 502 confirms an acceptable ground so that a ground fault trip is assured when a ground fault occurs Ground fault operation can be easily and safely tested on a de energized system The SE 502 resistance grounds the system ensure local electrical codes
10. pply 120 Vac 15 30 50 60 Hz 3 5 VA Dimensions Height 75 mm 3 0 100 mm 4 0 113 mm 4 4 Shipping 0 68 kg 1 5 Ib Ground Fault Circuit Trip Level eee 5 0 9mA Trip Time Class A GFCI 25 ms max 5 15 250 ms 15 100 75 ms max average of 10 or more measurements Pub SE 502 M April 25 2012 5 WARRANTY The SE 502 Ground Fault Ground Continuity Detector is warranted to be free from defects in material and workmanship for a period of five years from the date of purchase Littelfuse Startco will at Littelfuse Startco s option repair replace or refund the original purchase price of an SE 502 that is determined by Littelfuse Startco to be defective if it is returned to the factory freight prepaid within the warranty period This warranty does not apply to repairs required as a result of misuse negligence an accident improper installation tampering or insufficient care Littelfuse Startco does not warrant products repaired or modified by non Littelfuse Startco personnel Littelfuse Page 3 STARTCO SE 502 Ground Fault Ground Continuity Detector Rev 0 GROUND CONTINUITY TRIP ENABLE GROUND CONTINUITY TRIP DISABLE 2 FAILSAFE NON FAIL SAFE QH NOTES 1 DIMENS
11. trip which is indicated with an LED Pub SE 502 M April 25 2012 2 1 CONFIGURATION SWITCH SETTINGS See Fig 1 2 1 1 TRIP RELAY OPERATING MODE Switches and 2 are used to set the operating mode of the trip relay In the non fail safe mode the trip relay is energized when a trip occurs In the fail safe mode the trip relay is energized when the circuits are not tripped Non fail safe operation requires both switches to be in the non fail safe position Switches 1 and 2 do not affect operation of the ground fault and ground continuity annunciation relays 2 1 2 GROUND CONTINUITY TRIP Switch 3 is used to ENABLE or DISABLE ground continuity trip In the DISABLE position a loss of ground continuity will not cause a trip In the ENABLE position ground continuity loop resistance must increase above 50 for 15 to cause ground continuity trip ground continuity trip will not reset unless loop resistance is less than 25 In both switch positions ground continuity is indicated and the remote indication relay is energized when ground electrode loop resistance is less than 25 Q 2 2 FRONT PANEL INDICATION 2 2 1 GROUND FAULT The red LED labeled TRIP indicates a ground fault circuit trip See Section 2 3 The yellow LED labeled PRESENT indicates that a ground fault is present The ground fault annunciation relay is not energized The green LED labeled CLEAR indicates that a ground fault is not present The ground fault
12. uction there is a danger that the protection will be defeated A sympathetic ground fault trip is a trip that occurs on an unfaulted portion of a system when a ground fault occurs elsewhere in the system Sympathetic tripping can occur if capacitive current flowing to a ground fault from an unfaulted portion of the system is larger than the ground fault trip level Consequently coordination using conventional ground fault relays and zero sequence current detectors requires the ground fault trip level to be larger than the charging current of the largest protected portion of the system Since this trip level is usually larger than the unbalanced capacitive current flowing to ground due to unbalanced voltage and or capacitance to ground a coordinated well designed ground fault protection system will not have nuisance trips In small systems or systems with one ground fault relay sympathetic tripping is not a concern and nuisance tripping can be avoided if the ground fault trip level is larger than the unbalanced capacitive current flowing to ground Unfortunately this level is usually above the trip levels required for single phase Class A GFCI s and personnel protection must be achieved by other means In distribution and utilization systems protection is achieved by controlling touch and step potentials and by limiting the voltage to which exposed metal parts can rise during a ground fault no attempt is made to trip at the GFCI levels m
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