User Guide Model 380260 Insulation Tester / Megohmmeter
Introduction Congratulations on your purchase of Extech’s Insulation Tester/Megohmmeter. The Model 380260 provides three test ranges plus continuity and AC/DC voltage measurement. A handy test lock feature and a data hold function are also included. This professional meter, with proper care, will provide years of reliable service. Safety 1. Circuits under test must be de-energized and isolated before connections are made (except for voltage measurements). 2.
Operation Warning Ensure that the circuit under test does not include components that can be damaged by 1000VDC; such devices include power factor correction capacitors, low voltage mineral insulated cables, electronic light dimmers, and ballasts/starters for fluorescent lamps. Connecting Test Leads For all measurements, connect the red test lead to the V input terminal and the black test lead to the COM input terminal. Test Lead Check 1. Set the rotary switch to the 200range. 2.
Notes on IR (Megohmmeter) testing: 1. The maximum measurement range for the 380260 is 2000MΩ. Frequently, insulation resistance will exceed this value. When this happens, the display will indicate “1”, meaning the resistance is very high and the insulation being tested is good. 2. If the device being tested is highly capacitive, the display will indicate an increasing resistance value over time. Always wait until the reading has stabilized before recording the value. AC/DC Voltage Measurement 1.
Applications Measuring Power Tools and Small Appliances This section applies to any device under test that uses a line cord. For double insulated power tools, the meter’s leads should be connected to the device’s housing (chuck, blade, etc.) and the lines of the power cord. Testing AC Motors Disconnect the motor from the line by disconnecting the wires from the motor terminals or opening the mains switch.
Testing Cables 1. Disconnect the cable under test from the line. 2. Disconnect the opposite end of the cable to avoid errors as a result of leakage from other equipment. 3. Check each conductor to ground and/or lead sheath by connecting one meter lead to ground and/or lead sheath and the other meter lead to each of the conductors in turn. 4. Check insulation resistance between conductors by connecting meter leads to conductors in pairs. Refer to diagram at right.
General specifications Display LCD with dual display Sampling rate 2.5 readings per second Continuity beeper Ω, short circuit current <200mA, open circuit voltage 4.5V Over range indicator ‘1’ displayed Zero adjust Automatic Low battery indicator Low battery symbol displayed when battery voltage is low Environmental Installation category II, Pollution Degree 2, Altitude up to 2000 meters, Indoor use only Power source Six (6) 1.
Maintenance Battery Replacement When the low battery symbol appears on the LCD, the six 1.5V ‘AA’ batteries must be replaced. 1. Turn the meter off and remove the test leads 2. Unsnap the tilt stand from the rear of the meter 3. Remove the four Phillips head screws holding the battery cover 4. Remove the battery compartment cover 5. Replace the batteries observing polarity 6. Affix the rear cover and secure the screws. 7.
