The earth resistance measuring instrument Testboy TV 440 is suitable for checking the resistance between the ground reference and the connection point of the earthing system. Earth resistance measurements are prescribed for systems that are protected by automatic disconnection of the supply, as well as in lightning strike protection systems, telecommunications and fuel storage depots.

The auto Power-Off function prevents uncontrolled discharging of the batteries. The integrated timer turns the instrument off after five minutes of measurements; however, the Data-Hold function saves the last measurement result. The requirements for measuring resistances to earth are described in the standards DIN VDE 0413, Part 5 and EN 61557-5. Measurements for determining the earth resistance are carried out according to the current/voltage method. For measurement purposes, an alternating current is fed between the earth strip and the earth electrode to be measured. The voltage drop is measured and the earth resistance is determined with a probe positioned by the ground reference of the earth electrode to be measured. In this case, the alternating current prevents influences through polarisation at the junction between the metal earth electrode and earth. Measurements can be made according to the two- or three-wire principle.

Your advantages:
| 5 years manufacturer’s warranty
| TÜV / GS tested and approved
| IEC/EN 61010-1, DIN VDE 0411