Megger tests testers totally

Unlike many other currently available instrument test boxes, the new Megger MTB7671 checks all of the key operating parameters of instruments under test.

Users can, therefore, have complete confidence that the accuracy and performance of their instruments are maintained between routine calibrations, as required by the Guidance Notes that accompany the IEE Wiring Regulations.

Designed specifically to address the shortcomings of existing test boxes, which typically check only the primary functions of instruments, Megger's new MTB7671 also checks vital parameters, such as the voltage applied by the instrument during insulation tests.

Not only are the limits for these parameters laid down in the IEE Wiring Regulations and EN61557 which is called for in the 17th Edition, making them a mandatory part of the test procedure, they also have a huge effect on the validity of test results.

For example, if the insulation test voltage is too low, defective insulation may register as satisfactory - with potentially dangerous consequences.

The MTB7671 is capable of checking insulation testers, continuity testers, loop testers and RCD testers.

Test functions are colour coded to ensure ease of use, and pass/fail limits are incorporated for all parameters where such limits are published.

Instruments can, therefore, be checked quickly against a series of simple pass/fail indications.

For insulation testers, the MTB7671 provides confirmation that the instrument is producing the correct voltage and current, as well as checking calibration at five values from 0.25 megohm to 90 megohms.

Continuity testers are checked for correct output voltage and current, and for accuracy of resistance measurement at 0.5 ohm and 5 ohm.

When checking loop testers, the MTB7671 provides a direct loop measurement from the outlet socket, which can be measured either with a trip or a no-trip test.

It also offers loop plus 1 ohm and loop plus 180 ohm checks for verifying that instruments will give reliable results in TT installations.

For RCD testers, the MTB7671 provides RCD values of 10mA, 30mA and 100mA.

For each value, the five standard tests can be performed.

The test box is also provided with 230V output terminals to provide a quick check for instruments with voltage-measuring ranges, and its special design means that it can be safely used with either standard or RCD-protected supplies without the risk of tripping the supply.

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