Martindale Electric Company LTD Metrohm House Penfold Trading Estate Imperial Way Watford Herts WD24 4YY T: 01923 441717 F: 01923 446900 Email: sales@martindale-electric.co.uk web: www.martindale-electric.co.uk LITIN1000 ISSUE 1.1 01/01/004 IN1001/IN1003 ANALOGUE INSULATION & CONTINUITY TESTERS INSTRUCTION MANUAL Martindale Electric Company LTD Metrohm House Penfold Trading Estate Imperial Way Watford Herts WD24 4YY T: 01923 441717 F: 01923 446900 Email: sales@martindale-electric.co.uk web: www.martindale-electric.co.uk LITIN1000 ISSUE 1.1 01/01/004 IN1001/IN1003 ANALOGUE INSULATION & CONTINUITY TESTERS INSTRUCTION MANUAL
10. LIMITED WARRANTY Martindale Electric Company Ltd warrant instruments and test equipment manufactured by them to be free from defective material or factory workmanship and agree to repair or replace such products which, under normal use and service, reveal the defect to be the fault of our manufacturing, with no charge for parts and service. If we are unable to repair or replace the product, we will make a refund of the purchase price. Consult the Instruction Manual for instructions regarding the proper use and servicing of instruments and test equipment. Our obligation under this warranty is limited to repairing, replacing or making refund of any instrument or test equipment which proves to be defective within twenty four months from the date of original purchase. This warranty does not apply to any of our products which have been repaired or altered by unauthorised persons in any way so as, in our sole judgement, to degrade their stability or reliability, or which have been subject to misuse, abuse, misapplication, negligence or accident or which have had the serial numbers altered, defaced or removed. Accessories not of our manufacture, used with this product, are not covered by this warranty. To register a claim under the provisions of this warranty, return the instrument to Martindale Electric Company Ltd, Metrohm House, Penfold Trading Estate, Watford, WD24 4YY. Upon our receipt and inspection of the product we will advise you as to the outcome of your claim. ALL WARRANTIES IMPLIED BY LAW ARE HEREBY LIMITED TO A PERIOD OF 24 MONTHS, AND THE PROVISIONS OF THE WARRANTY ARE EXPRESSLY IN LIEU OF ANY OTHER WARRANTIES EXPRESSED OR IMPLIED. The purchaser agrees to assume all liability for any damages and bodily injury which may result from the use or misuse of the product by the purchaser, his employees, or others, and the remedies provided for in this warranty are expressly in lieu of any other liability Martindale Electric Company Ltd may have including incidental or consequential damages. Martindale Electric Company Ltd reserves the right to discontinue models at any time, or change specification, price or design, without notice and without incurring any obligation. TABLE OF CONTENTS 1. SYMBOLS 2. SAFETY RULES 3. DESCRIPTION 4. OPERATING INSTRUCTIONS 5. SPECIFICATION 5.1 ELECTRICAL 5.2 MECHANICAL 5.3 ENVIRONMENTAL 6. FUSED LEADS 7. SPARES & ACCESSORIES 8. REPAIRS 9. CLEANING 10. LIMITED WARRANTY 2 2-5 6 7-10 11-11 16 10. LIMITED WARRANTY Martindale Electric Company Ltd warrant instruments and test equipment manufactured by them to be free from defective material or factory workmanship and agree to repair or replace such products which, under normal use and service, reveal the defect to be the fault of our manufacturing, with no charge for parts and service. If we are unable to repair or replace the product, we will make a refund of the purchase price. Consult the Instruction Manual for instructions regarding the proper use and servicing of instruments and test equipment. Our obligation under this warranty is limited to repairing, replacing or making refund of any instrument or test equipment which proves to be defective within twenty four months from the date of original purchase. This warranty does not apply to any of our products which have been repaired or altered by unauthorised persons in any way so as, in our sole judgement, to degrade their stability or reliability, or which have been subject to misuse, abuse, misapplication, negligence or accident or which have had the serial numbers altered, defaced or removed. Accessories not of our manufacture, used with this product, are not covered by this warranty. To register a claim under the provisions of this warranty, return the instrument to Martindale Electric Company Ltd, Metrohm House, Penfold Trading Estate, Watford, WD24 4YY. Upon our receipt and inspection of the product we will advise you as to the outcome of your claim. ALL WARRANTIES IMPLIED BY LAW ARE HEREBY LIMITED TO A PERIOD OF 24 MONTHS, AND THE PROVISIONS OF THE WARRANTY ARE EXPRESSLY IN LIEU OF ANY OTHER WARRANTIES EXPRESSED OR IMPLIED. The purchaser agrees to assume all liability for any damages and bodily injury which may result from the use or misuse of the product by the purchaser, his employees, or others, and the remedies provided for in this warranty are expressly in lieu of any other liability Martindale Electric Company Ltd may have including incidental or consequential damages. Martindale Electric Company Ltd reserves the right to discontinue models at any time, or change specification, price or design, without notice and without incurring any obligation. -16- -16- TABLE OF CONTENTS 1. SYMBOLS 2. SAFETY RULES 3. DESCRIPTION 4. OPERATING INSTRUCTIONS 5. SPECIFICATION 5.1 ELECTRICAL 5.2 MECHANICAL 5.3 ENVIRONMENTAL 6. FUSED LEADS 7. SPARES & ACCESSORIES 8. REPAIRS 9. CLEANING 10. LIMITED WARRANTY 2 2-5 6 7-10 11-11 16
1 SYMBOLS 7. SPARES AND ACCESSORIES Caution (risk of electric shock). Test Leads, Standard Kit: Fused Leads: Fuse 5x20mm 500mA 250V HBC FAST BLOW: Battery 1.5V IEC LR6 (MN00), Alkaline TL47 (DFK100) TL57 FUSE500250 8. REPAIRS Caution (refer to instruction manual). NOTE: Before returning the instrument for repair please check that the following are in correct working order: 1) The condition of the batteries and that they are inserted correctly in the battery compartment. 2) The test leads are not faulty. 2 SAFETY RULES Equipment protected by DOUBLE INSULATION or REINFORCED INSULATION CAUTION RISK OF ELECTRIC SHOCK DISCONNECT TEST LEADS BEFORE OPENING TESTER 3) If the fuse is either blown or not fitted correctly the buzzer will sound and the movement will read reverse when the continuity range is selected, with the test leads disconnected. Please return the tester to: Martindale Electric Company Ltd Metrohm House Penfold Trading Estate Imperial Way Watford WD24 4YY 9 CLEANING Clean the instrument case with an anti-static cleaner and wipe with a dry cloth. -2- -- 1 SYMBOLS 7. SPARES AND ACCESSORIES Caution (risk of electric shock). Test Leads, Standard Kit: Fused Leads: Fuse 5x20mm 500mA 250V HBC FAST BLOW: Battery 1.5V IEC LR6 (MN00), Alkaline TL47 (DFK100) TL57 FUSE500250 8. REPAIRS Caution (refer to instruction manual). NOTE: Before returning the instrument for repair please check that the following are in correct working order: 1) The condition of the batteries and that they are inserted correctly in the battery compartment. 2) The test leads are not faulty. 2 SAFETY RULES Equipment protected by DOUBLE INSULATION or REINFORCED INSULATION CAUTION RISK OF ELECTRIC SHOCK DISCONNECT TEST LEADS BEFORE OPENING TESTER 3) If the fuse is either blown or not fitted correctly the buzzer will sound and the movement will read reverse when the continuity range is selected, with the test leads disconnected. Please return the tester to: Martindale Electric Company Ltd Metrohm House Penfold Trading Estate Imperial Way Watford WD24 4YY 9 CLEANING Clean the instrument case with an anti-static cleaner and wipe with a dry cloth. -2- --
5.2 MECHANICAL Size: Material: Weight: Movement: Scale length: Sockets: Test leads: 5.3 ENVIRONMENTAL 190 x 90 x 54mm Polycarbonate/ABS 0.5kg(less carrying case) 1mA sensitivity Taut Band 70mm 4mm shrouded 1m long leads fitted with non retractable shrouded plugs and shrouded crocodile clips This tester has been designed with your safety in mind. However, no design can completely protect against incorrect use. Electrical circuits can be dangerous and/or lethal when lack of caution or poor safety practices are used. When using this tester to monitor high voltages turn off the power before connecting the tester. Where possible, do not touch the tester or its leads when the power is on. Turn off the power before disconnecting the tester. Operating Temperature: 0º to +40ºC Storage Temperature: -20ºC to +70ºC Humidity: 90% at 40ºC 6. FUSED LEADS CAUTION READ THE MANUAL These instruments have been designed to comply with BS EN 61010, and are safe to use with the two leads, clips and probes that are provided as standard. HSE guidance GS38 recommends the use of fused leads. These can be purchased as accessories if desired. Read this Instruction Manual carefully and completely. Voltages within the capability of this tester can be hazardous. Follow the instructions in this Manual for every measurement. Read and understand the general instructions before attempting to use this tester. SAFETY CHECK Before using the tester check the condition of the batteries and fuse. NOTE: The condition of the fuse can be checked by selecting the continuity range and if the buzzer sounds the fuse is either blown or not inserted properly in the fuse holder. Battery and fuse replacement are described later in these operating instructions. -- -3-5.2 MECHANICAL Size: Material: Weight: Movement: Scale length: Sockets: Test leads: 5.3 ENVIRONMENTAL 190 x 90 x 54mm Polycarbonate/ABS 0.5kg(less carrying case) 1mA sensitivity Taut Band 70mm 4mm shrouded 1m long leads fitted with non retractable shrouded plugs and shrouded crocodile clips This tester has been designed with your safety in mind. However, no design can completely protect against incorrect use. Electrical circuits can be dangerous and/or lethal when lack of caution or poor safety practices are used. When using this tester to monitor high voltages turn off the power before connecting the tester. Where possible, do not touch the tester or its leads when the power is on. Turn off the power before disconnecting the tester. Operating Temperature: 0º to +40ºC Storage Temperature: -20ºC to +70ºC Humidity: 90% at 40ºC 6. FUSED LEADS CAUTION READ THE MANUAL These instruments have been designed to comply with BS EN 61010, and are safe to use with the two leads, clips and probes that are provided as standard. HSE guidance GS38 recommends the use of fused leads. These can be purchased as accessories if desired. Read this Instruction Manual carefully and completely. Voltages within the capability of this tester can be hazardous. Follow the instructions in this Manual for every measurement. Read and understand the general instructions before attempting to use this tester. SAFETY CHECK Before using the tester check the condition of the batteries and fuse. NOTE: The condition of the fuse can be checked by selecting the continuity range and if the buzzer sounds the fuse is either blown or not inserted properly in the fuse holder. Battery and fuse replacement are described later in these operating instructions. -- -3-
Double check the switch setting, and lead connections before making measurements. Are you following the instructions? Disconnect the tester or turn off the power before changing switch positions. When replacing fuses use only specified types and insert correctly in the fuse holder. When changing the battery, fuse, or removing the cover to access the internal circuitry, always disconnect the test leads. General Safety: LVD: Meets BS EN 61010-1 EMC: Meets BS EN 50081-1 BS EN 50082-1 Battery: 6 off 1.5V, AA IEC LR6 (MN00) Alkaline Fuse: 500mA, 5 x 20mm, HBC (ceramic), 250V Fast Blow DON T TOUCH Don t touch exposed wiring, connection or other live parts of an electrical circuit. If in doubt, check the circuit first for voltage before touching it. Turn off the power to a circuit before connecting test probes to it. Be sure there is no voltage present before you touch the circuit. Do not use cracked or broken test leads. Do not use in wet conditions. -4- -13- Double check the switch setting, and lead connections before making measurements. Are you following the instructions? Disconnect the tester or turn off the power before changing switch positions. When replacing fuses use only specified types and insert correctly in the fuse holder. When changing the battery, fuse, or removing the cover to access the internal circuitry, always disconnect the test leads. General Safety: LVD: Meets BS EN 61010-1 EMC: Meets BS EN 50081-1 BS EN 50082-1 Battery: 6 off 1.5V, AA IEC LR6 (MN00) Alkaline Fuse: 500mA, 5 x 20mm, HBC (ceramic), 250V Fast Blow DON T TOUCH Don t touch exposed wiring, connection or other live parts of an electrical circuit. If in doubt, check the circuit first for voltage before touching it. Turn off the power to a circuit before connecting test probes to it. Be sure there is no voltage present before you touch the circuit. Do not use cracked or broken test leads. Do not use in wet conditions. -4- -13-
Insulation (MΩ) 0-50MΩ (250V) 0-100MΩ (500V) 0-200MΩ (1000V) HIGH VOLTAGE IS DANGEROUS Always start with the power turned off. Be sure there is no voltage present before making connections to the circuit. Test Voltage: Model IN10001: 500V DC -0+20% (Current) with a load of 0.5MΩ (1mA) Model IN1003: 250V DC -0+20% with a load of 0.25MΩ (1mA) 500V DC -0+20% with a load of 0.5MΩ (1mA) or 1000V DC -0+20%with a load of 1MΩ (1mA) ±1.6mm of scale arc length Before disconnecting the tester, turn the circuit off and wait for the meter to return to zero. SAFETY IS NO ACCIDENT! THIS INSTRUMENT SHOULD ONLY BE USED BY A COMPETENT, SUITABLY TRAINED PERSON. Battery Consumption: (Nominal) 60mA: 250V DC into 0.25MΩ 100mA: 500V DC into 0.5MΩ 200mA: 1000V DC into 1MΩ REMEMBER SAFETY IS NO ACCIDENT! -12- -5- Insulation (MΩ) 0-50MΩ (250V) 0-100MΩ (500V) 0-200MΩ (1000V) HIGH VOLTAGE IS DANGEROUS Always start with the power turned off. Be sure there is no voltage present before making connections to the circuit. Test Voltage: Model IN10001: 500V DC -0+20% (Current) with a load of 0.5MΩ (1mA) Model IN1003: 250V DC -0+20% with a load of 0.25MΩ (1mA) 500V DC -0+20% with a load of 0.5MΩ (1mA) or 1000V DC -0+20%with a load of 1MΩ (1mA) ±1.6mm of scale arc length Before disconnecting the tester, turn the circuit off and wait for the meter to return to zero. SAFETY IS NO ACCIDENT! THIS INSTRUMENT SHOULD ONLY BE USED BY A COMPETENT, SUITABLY TRAINED PERSON. Battery Consumption: (Nominal) 60mA: 250V DC into 0.25MΩ 100mA: 500V DC into 0.5MΩ 200mA: 1000V DC into 1MΩ REMEMBER SAFETY IS NO ACCIDENT! -12- -5-
3. DESCRIPTION The IN1000 Series analogue insulation and continuity testers are designed to carry out testing in accordance with International standards, including BS EN657 & BS7671. There are two variants available, the 500V only IN1001 and the 250/500/1000V IN1003. The instruments are powered by six 1.5 volt manganese alkaline batteries type LR6 (MN00). The instruments are supplied in a carrying case which contains the instruction book, test leads and clips. The carrying case has been designed to allow the tester to be operated in the case. The models have a push to operate and turn to latch test button on the insulation ranges as standard. On completion of an insulation test, a latched test button has to be manually released to discharge the installation under test. In the interest of safety the user should be aware of this. 5. SPECIFICATION IN1001/IN1003 5.1 ELECTRICAL Voltage V~ 0-500V AC ±3% of Full Scale Input Impedance: 250KΩ nominal Continuity (Ω) 0-2Ω Test Voltage: 4V DC min Short Circuit Current: 200mA min ±1.6mm of scale arc Battery Consumption: 230mA nominal Buzzer Current Consumption: Operates below 1Ω On all ranges: buzzer operates after 4 min if tester is switched on. 240mA nominal Resistance 0-200Ω Test Voltage: 4V DC min Short Circuit Current: 20mA min ±1.6mm of scale arc Battery Consumption: 25mA nominal -6- -11-3. DESCRIPTION The IN1000 Series analogue insulation and continuity testers are designed to carry out testing in accordance with International standards, including BS EN657 & BS7671. There are two variants available, the 500V only IN1001 and the 250/500/1000V IN1003. The instruments are powered by six 1.5 volt manganese alkaline batteries type LR6 (MN00). The instruments are supplied in a carrying case which contains the instruction book, test leads and clips. The carrying case has been designed to allow the tester to be operated in the case. The models have a push to operate and turn to latch test button on the insulation ranges as standard. On completion of an insulation test, a latched test button has to be manually released to discharge the installation under test. In the interest of safety the user should be aware of this. 5. SPECIFICATION IN1001/IN1003 5.1 ELECTRICAL Voltage V~ 0-500V AC ±3% of Full Scale Input Impedance: 250KΩ nominal Continuity (Ω) 0-2Ω Test Voltage: 4V DC min Short Circuit Current: 200mA min ±1.6mm of scale arc Battery Consumption: 230mA nominal Buzzer Current Consumption: Operates below 1Ω On all ranges: buzzer operates after 4 min if tester is switched on. 240mA nominal Resistance 0-200Ω Test Voltage: 4V DC min Short Circuit Current: 20mA min ±1.6mm of scale arc Battery Consumption: 25mA nominal -6- -11-
INSULATION 500V (0-100MΩ) With the function switch in the MΩ 500V position, a test voltage of 500V DC is selected. The insulation resistance is measured on the red scale when the test button is operated. 4. OPERATING INSTRUCTIONS IN2001/IN2003 Series INSULATION 1000V (0-200MΩ) With the function switch in the MΩ 1000V position, a test voltage of 1000V DC is selected. The insulation resistance is measured on the red scale when the test button is operated and the measured value is multiplied by 2. CAPACITANCE DISCHARGE When testing insulation, the equipment under test should remain connected after releasing the test switch. This discharges any equipment capacitance via the tester, the warning lamp indicating the period of discharge. Fig.1 Fig. 1 illustrates the front layout of a model IN1003 tester. The function switch selects AC Voltage/ power OFF (V~, OFF), Continuity with buzzer (Ω x1), Resistance (Ω x100) and Insulation (MΩ) in three positions, with test voltages of 250V, 500V and 1000V DC respectively. On the IN1001 model there is only one MΩ position with a test voltage of 500V DC. AC Voltage in the range 0-500V is measured on the blue scale of the analogue meter when the function switch is in the OFF position. The Continuity (Ω) and Resistance (Ω x100) ranges are activated when selected by the function switch. -10- -7- INSULATION 500V (0-100MΩ) With the function switch in the MΩ 500V position, a test voltage of 500V DC is selected. The insulation resistance is measured on the red scale when the test button is operated. 4. OPERATING INSTRUCTIONS IN2001/IN2003 Series INSULATION 1000V (0-200MΩ) With the function switch in the MΩ 1000V position, a test voltage of 1000V DC is selected. The insulation resistance is measured on the red scale when the test button is operated and the measured value is multiplied by 2. CAPACITANCE DISCHARGE When testing insulation, the equipment under test should remain connected after releasing the test switch. This discharges any equipment capacitance via the tester, the warning lamp indicating the period of discharge. Fig.1 Fig. 1 illustrates the front layout of a model IN1003 tester. The function switch selects AC Voltage/ power OFF (V~, OFF), Continuity with buzzer (Ω x1), Resistance (Ω x100) and Insulation (MΩ) in three positions, with test voltages of 250V, 500V and 1000V DC respectively. On the IN1001 model there is only one MΩ position with a test voltage of 500V DC. AC Voltage in the range 0-500V is measured on the blue scale of the analogue meter when the function switch is in the OFF position. The Continuity (Ω) and Resistance (Ω x100) ranges are activated when selected by the function switch. -10- -7-
The test switch is operated only when performing insulation tests, activating the insulation circuitry when pressed and discharging the line when released. The test switch can be operated as a momentary or latching action. To latch it, the switch should be pressed and rotated clockwise. To release it, the switch should be rotated anti-clockwise. Always switch off the tester after use. If the tester is inadvertently left on or is in continuous use, the buzzer will sound after approximately 4 minutes indicating the tester is on. The buzzer can be reset by switching the tester off and then on again. ZERO ADJUST If the pointer does not coincide with the zero line on the left side of the scale, adjust as required. Ensure tester is switched off and leads are disconnected, adjust using a small screwdriver inserted through the access hole in the rear centre of the tester. The hole is covered by a protective cap which must be removed then replaced after adjustment. Clean the instrument regularly with antistatic cleaner to avoid zero errors caused by static (see 9. CLEANING - page ). BATTERY CHECK Ensure that the tester is switched off. With the test leads shorted and the function switch in the MΩ 1000V position for IN1003 models (MΩ 500V position for IN1001) press the Test switch and the pointer should read within the bat mark on the scale. If not, replace the batteries. FUSE The fuse is located in the battery compartment and is used to protect the tester if the leads are connected to a live circuit when the continuity/resistance ranges are selected. NOTE: The condition of the fuse can be checked by selecting the continuity range, with the test leads disconnected, and if the fuse is either blown or not fitted properly the buzzer will sound and the pointer will read reverse. To replace the fuse, switch the tester off, disconnect the test leads, remove the battery cover and the blown fuse then replace with a fuse of the correct type and rating. Fuse type 500mA HBC, see Spares and Accessories (page ). Do not use a glass fuse. VOLTAGE 0-500V AC Select (V~, OFF) position on the function switch. Connect test leads to the circuit under test and the voltage is measured on the blue scale. If the tester is connected to a live circuit the warning lamp will illuminate no matter what the position of the function switch, but doing so on the continuity range will result in the fuse blowing. Always check if the circuit under test is live with (V~, OFF) selected before carrying out continuity or insulation tests. CONTINUITY WITH BUZZER 0-2Ω With the function switch in the Ω x1 position, the continuity resistance is measured on the green scale. If the continuity resistance is less than 1Ω the buzzer will sound. BATTERY REPLACEMENT Ensure that the tester is switched OFF. Disconnect test leads and slacken the captive screws on the battery cover. Lift off the battery cover, remove the spent batteries and replace with new ones. Six X 1.5 volt alkaline type LR6 (MN00). RESISTANCE (0-200Ω) With the function switch in the Ωx100 position, resistance is measured on the green scale and the measured value multiplied by 100. INSULATION 250V (0-50MΩ) With the function switch in the MΩ 250V position, a test voltage of 250V DC is selected. The insulation resistance, 0-200MΩ is measured on the red scale when the test button is operated and the measured value multiplied by ½. -8- -9- The test switch is operated only when performing insulation tests, activating the insulation circuitry when pressed and discharging the line when released. The test switch can be operated as a momentary or latching action. To latch it, the switch should be pressed and rotated clockwise. To release it, the switch should be rotated anti-clockwise. Always switch off the tester after use. If the tester is inadvertently left on or is in continuous use, the buzzer will sound after approximately 4 minutes indicating the tester is on. The buzzer can be reset by switching the tester off and then on again. ZERO ADJUST If the pointer does not coincide with the zero line on the left side of the scale, adjust as required. Ensure tester is switched off and leads are disconnected, adjust using a small screwdriver inserted through the access hole in the rear centre of the tester. The hole is covered by a protective cap which must be removed then replaced after adjustment. Clean the instrument regularly with antistatic cleaner to avoid zero errors caused by static (see 9. CLEANING - page ). BATTERY CHECK Ensure that the tester is switched off. With the test leads shorted and the function switch in the MΩ 1000V position for IN1003 models (MΩ 500V position for IN1001) press the Test switch and the pointer should read within the bat mark on the scale. If not, replace the batteries. FUSE The fuse is located in the battery compartment and is used to protect the tester if the leads are connected to a live circuit when the continuity/resistance ranges are selected. NOTE: The condition of the fuse can be checked by selecting the continuity range, with the test leads disconnected, and if the fuse is either blown or not fitted properly the buzzer will sound and the pointer will read reverse. To replace the fuse, switch the tester off, disconnect the test leads, remove the battery cover and the blown fuse then replace with a fuse of the correct type and rating. Fuse type 500mA HBC, see Spares and Accessories (page ). Do not use a glass fuse. VOLTAGE 0-500V AC Select (V~, OFF) position on the function switch. Connect test leads to the circuit under test and the voltage is measured on the blue scale. If the tester is connected to a live circuit the warning lamp will illuminate no matter what the position of the function switch, but doing so on the continuity range will result in the fuse blowing. Always check if the circuit under test is live with (V~, OFF) selected before carrying out continuity or insulation tests. CONTINUITY WITH BUZZER 0-2Ω With the function switch in the Ω x1 position, the continuity resistance is measured on the green scale. If the continuity resistance is less than 1Ω the buzzer will sound. BATTERY REPLACEMENT Ensure that the tester is switched OFF. Disconnect test leads and slacken the captive screws on the battery cover. Lift off the battery cover, remove the spent batteries and replace with new ones. Six X 1.5 volt alkaline type LR6 (MN00). RESISTANCE (0-200Ω) With the function switch in the Ωx100 position, resistance is measured on the green scale and the measured value multiplied by 100. INSULATION 250V (0-50MΩ) With the function switch in the MΩ 250V position, a test voltage of 250V DC is selected. The insulation resistance, 0-200MΩ is measured on the red scale when the test button is operated and the measured value multiplied by ½. -8- -9-