Testboy TV 440N0 pages

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
Technical Details
Testboy TV 440N
Display
LC-Display, 3½digit
Measurement Range earth resistance
20 Ω, 200Ω, 2000Ω ±2%+3digit
earth voltage
0 to 200V, 40 to 400Hz, ±1,5%+5digit
Resolution
0,01Ω at 20 Ω
0,1Ω at 200Ω
1Ω at 2000Ω
Measuring System
constant current, 2mA
Power Supply
6x 1,5V
Overload Category
CAT III 600V
Dimension
168 x 110 x 62mm
Protection
IP 40