IR750 INSULATION AND CONTINUITY TESTER
Contents
1. 1000V 20 0 at 1 0MQ 4 5 6 5V o c 200mA s c Power Supply 4x 1 5V alkaline type batteries IEC No LRS Satety Features Voltage mode indicates the presence of external voltage In excess of approximately 30V Fuse protection for internal faults Capacitive circuits automatically discharged when push switch is released Voltage Range Maximum 500V AC Operation Storage Temp Range 0 C to 40 C 20 C to 70 C Humidity 75 Relative Humidity 90 Relative Humidity 40 C Maximum up to 35 C Max up to 35 C Temp Coeff 0 1 per C The minimum range of environmental conditions for which the equipment is designed is as follows indoor use altitude up to 2000M installation category IL e pollution degree 2 Size 200mm x 95mm x 55mm Weight 500 grammes Additional Feature Momentary test switch Automatic low battery indicator Robust case High Impact ABS Fuses 250mA 20mm IEC 127 F 500mA 1 1 600V HRC Fuses should only be replaced by the same type and rating Due toa policy of continuous development Seaward Electronic Limited reserve the right to alter the equipment specification and description outlined in this publication with out prior notice and no part of this publication shall be deemed to be any part of any contract for the equipment unless specifically referred to as an inclusion within such contract2. IR750 INSULATION AND CONTINUITY TESTER OPERATING INSTRUCTIONS 182A910 IR750A 1824911 IR750B 182A912 CONTENTS Introduction Operating Procedures Tests and Regulations Specification E SEAWARD ELECTRONIC LTD Bracken Hill South West Industrial Estate Peterlee Co Durham SR8 2SW England Tel 0191 586 3511 Fax 0191 586 0227 www seaward co uk sales seaward co uk calibration seaward co uk MENT SHOULD ONLY BE USED BY COMPETENT SUITABLY TRAINED PERSON NEL AFTER DUE CONSIDERATION GF ANY HAZARD INVOLVED READ INSTRUCTIONS BEFORE USE Due to the potential hazards associated with any electrical circuit it is important that a user is fully familiar with instruc tions covering the capabilities applications and operations of the instrument The user should ensure that all reasonable safety proce dures are followed and if any doubt exists should seek advice before proceeding Symbols used on this equipment m Equipment protected throughout by double or rein forced insulation A Caution Risk of electric shock A Caution refer to accompanying documents 1R750 insulation Continuity Tester Introduction The 1R750 is a compact hand held igital insulation continu ity tester with a 3 2 digit liquid crystal display he unit is contained in a rugged enclosure with test lead terminals at the upper end of the instrument and a battery compartment at the rear The controls cons
3. test leads should be checked initially insulation Resistance Measurement Ensure that the circuit under test is de energised Connect the test leads to the instrument and check their condition by the procedure detailed under Test Leads Select the MQ range Connect the test leads to the terminals of the circuit to be tested If the instrument indicates that volts are present do not proceed with the test When no voltage is indicated pressing the test switch will indicate an insulation resistance measurement from 0 1999MQ on the display at a test volt age of 1000V DC if the MQ 1 0kV position has been select ed 500V DC test voltage at the MQ 500V setting or 250V DC test voltage at the MQ 250V setting Resistance values greater than 1999MQ will generate an over range indication of a blank display and the digit 1 An auto ranging circuit in the IR750 ensures maximum resolu tion of reading on the MQ insulation resistance scales by changing range at low MQ readings The IR750 contains a discharge path which will discharge a capacitive circuit after insulation testing Continuity Measurement Ensure that the circuit under test is de energised Connect the test leads to the instrument and check their condition by the procedure detailed under Test Leads Select the 20Q range Connect the leads to the circuit to be tested If volts are pre sent unit will give audible warning and change to voltage indication mode and display wi
4. ELY 15 MINUTES THE IR750 WILL ENTER AUTO SHUT OFF MODE TO PROLONG BATTERY LIFE SWITCH TO OFF POSITION TO RE SET ALLOW 5 SECONDS FOR THE AUTO SHUT OFF CIRCUITRY TO RE SET 5 THE LEAD ADJUST FEATURE HAS A PRECISION OF 10mQ AFTER USING THIS FEATURE IT WILL NOT BE UNCOMMON FOR A SUBSEQUENT CHECK TO INDICATE A SLIGHTLY DIFFERENT READING THIS WILL BE DUE TO A SMALL CHANGE IN THE CON TACT RESISTANCE OF THE SHORTED LEADS 6 IF REPAIR IS NECESSARY IT SHOULD BE RETURN ED TO SEAWARD ELECTRONIC LIMITED ADDRESS ON FRONT COVER IEE Wiring Regulations Test requirements for Continuity and Insulation Resistance measurements as defined in the guidance notes to the 16th Edition IEE Wiring Regulations are summarised as follows Continuity of Ring Circuit Conductors Regulation The aspect to be noted in this test is that although the Regulation concerned calls for the continuity of all conduc tors in a ring to be verified to ensure that there are no inter connecting multiple loops the suggested method of testing requires a measurement to be undertaken METHOD a Temporarily connect a phase conductor of one leg of the ring and the neutral conductor of the other leg b Measure the resistance between the remaining ie inward phase and outward neutral phase and neutral con ductors c A finite reading will confirm no open circuit on the ring conductors under test d Temporarily bridge the remaining phase neutral conduc tors e M
5. easure and note the resistance between phase and neutral contacts at each socket outlet around the ring t The readings should be substantially the same provided no multiple loops exist g Where the protective conductor is in the form of a ring Carry out the procedure in a above but for neutral con ductor read protective conductor h Measure the resistance between the remaining live con ductor and the remaining unconnected circuit protective con ductor at the origin of the circuit i A finite reading confirms no open circuit j Temporarily bridge the remaining circuit protective con ductor and live conductor k Measure the resistance between the circuit protective conductor and live conductor contacts at each socket outlet around the ring 1 The readings equal to R1 and R2 tor the circuit should be substantially the same provided no multipie loop present NOTE R1 is the phase conductor and R2 is the protective conductor Continuity of Protective Conductors Regulation This regulation requires every protective conductor to be separately tested to verify that it is electrically sound and correctly connected It should be noted that a That any extraneous conductive part used for equipoten tial bonding shall be included in this test b That the test should not only be carried out before the supply is connected but also before any other test involving these conductors is made The source of energy for the
6. eptable level it should be noted that when the insulation resistance scale has been selected the Low Bat sign may illuminate when testing low values of insulation resistance and this should be regarded merely as a warning that high power is being consumed from the internal batteries and that the user should avoid continuous testing under these conditions Battery Life I 9 n gt For long battery life it is recommended that the unit is switched off when not in use Battery Installation Four LR6 alkaline type batteries should be fitted into the base of the instrument and these should be replaced where necessary with batteries of similar type NOTE Before removing the battery cover the test leads MUST be removed from the unit for safety reasons and the unit must be switched off Cleaning A non wetting non abrasive material should be used Test Leads Before any test always check the condition of the test leads by y a inspecting tor any signs of damage to the insulation or breakage to the internal conductors b inserting the red test lead into the red terminal socket of the instrument and the black test lead into the black terminal socket and bringing the test lead probes or clips together On rotating the rotary switch to the 202 pos ition and pressing test switch a low resistance reading should be obtained A high resistance reading or the over range symbol requires investigation The connec tions an the state of the
7. ist of a six position rotary switch to select the test function and a test switch When the test function is selected the test switch may be pressed for testing on any function The R7508 is the same as the IR750 in all respects with the exception of the 250V and 1KV range and the lead adjust facility The IR750A is the same as the IR750 in all respects with the exception of the 250V and 1KV ranges Essential Operating Procedure with the 1R750 1 Before testing always check the test leads by the proce dures detailed under Test Leads 2 Always ensure that the leads are fully inserted into the instrument before undertaking any testing 3 Always inspect the condition of the unit before use If damaged do not use 4 Only when no voltage exists shouid either the continuity scale or the insulation resistance scale be selected WARNING The IR750 contains a solid state inverter which produces a voltage of 250V DC 500V DC or 1000V DC for insulation testing The instrument must therefore be treated with the necessary respect when the insulation resistance functions are being used The voltage present indication will be activated when voltage in excess of 30V and less than 500V is present If a voltage is present do NOT press the test switch Liquid Crystal Display The liquid crystal display of the IR750 provides additional symbols a live voltage indication and a low battery indica tion when the battery condition falls to an unacc
8. ll indicate the voltage When no voltage is indicated press the test switch the display will now show the resistance of the circuit under test plus the resistance of the test leads Lead Adjust Facility When on 20Q range there is a feature for the unit to account for the resistance of the test leads To operate short the ends of the test leads together press the test switch display will show the resistance of the leads now press the lead adjust switch Display should now show c 0Q Lead adjust may not zero exactly first time if this is the case repeat the above procedure Any resistance measurements will now be those of the circuit under test This facility will be turned off when another range is selected Resistance readings up to 19 99 ohms can be obtained on the display Any resistance above this figure will generate an over range indication of a blank display and the digit 1 In such circumstances the instrument should be used on the 2KQ range When a resistance of less than 1000 ohms is encountered on the 2KQ range the instrument will produce an audio bleep This auto continuity sounder provides rapid continuity checking NOTE 1 DO NOT PROCEED TO CONTINUITY OR INSULATION RESISTANCE TESTING IF THE VOLTAGE INDICA TION IS ACTIVATED 2 THIS INSTRUMENT IS PROTECTED BY FUSES WHICH MAY RUPTURE IF THESE OPERATING INSTRUCTIONS ARE NOT FOLLOWED 3 NO ATTEMPT SHOULD BE MADE TO DISMANTLE THE INSTRUMENT 4 AFTER APPROXIMAT
9. ll resistance readings obtained must not be less than the minimum values as detailed in the following table MINIMUM VALUES OF INSULATION RESISTANCE Circuit nominal Voltage Minimum Insulation Resistance M ohms Test Voltage DC Extra low voltage circuits when the circuit is supplied from a safety 250 isolating transformer Up to and including 500V with thi exception of the above s Over 500V up to 1000V Between SELV circuits amp associated LV circuits 3750 rms AC for 1 minute 5 0 Additional withstand test if required e g Uo 240V TEST METHODS At appropriate switchboard Three Phase Test between phase Test between and neutral Phase 2 Hive conductors conductors Phase 1 to Phase 3 Neutral Phase 3 Neutral Phase 2 to Phase 3 to Neutral either singly or grouped Test between phase Test betwe Tost batwel between all conductors conductors amp earth earth where low readings are obtained SPECIFICATION Seaward 1R750 Insulat Ten tinuity Tester 0 1999MQ with 2 auto ranging 2 digit on seiecln va MQ sange voltages of 0 100MQ 250V 500V t amp 1000V o19 990 ai 2 0 2KQ 2 digits Voitage 30 500V acide indication Continuity Audible indication Sounder of resistance below c 1000 ohms on 2KQ Range Lead Adjust 049 0 05 ohm h 2 digit 250V 20 0 at 0 25MQ 500V 20 0 at 0 5MQ
10. test instrument should therefore be from an alternative source e g a battery c The resistance of the protective conductor is required if the method defined in Regulation 413 02 12 of limitin the impedance of the protective conductor to the values in Table 41C is employed to meet the required disconnection times Method 1 Strap phase and protective conductor at the Distribution Board and test between phase and earth termi nals at each outlet in the circuit Method 2 With one terminal of the tester connected to the installation s earth terminal and a test lead connected to the other terminal of the tester obtain resistance measurements by making contact with the protec conductor at various points on the circuit e g lighting fittings switches etc The resistance of the test leads should be deducted from any resistance readings obtained Insulation Resistance Regulation The Regulation requires the insulation resistance of conduc tors and electrical accessories to be measured to verify their compliance within defined standards and that electrical con ductors or protective conductors are not short circuited The Regulation details Fs a The need to isolate voitage sensitive devices in order that they are not damaged by the test values b The requirement to disconnect pilot or indicator lamps and capacitors to avoid inaccurate test values c That all fuses should be in place lamps removed and switches closed d That a
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