METREL MI 3399, Инструкция с упражнениями

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Electrical Installation Safety Trainer AD 1 - MI 3399
120
When setting the limits the following thresholds should be considered:
o
2
Ω
above ground,
o
10
Ω
for the complete system,
o
20
Ω
for a single wire or
o
8% of the specific earth resistance.
3 The measurement is done with two clamps:
o
Current clamps (A1018). These clamps measure the current induced by the
generator clamps. They can also be used when measuring leakage
currents.
o
Generator clamps (A1019). These clamps insert current into the circuit and
measure the voltage drop.
Both clamps are placed either on the earth electrode or on the PE (or even PEN)
conductor. When checking lightning systems and earth loops both clamps are
connected to the lightning rods around the building.
4 Press the START key.
Expected results
Allowed earth resistance is 10
Ω which is usually achieved in a TN system. When lightning
systems are checked the measured earth resistance must be below this value to ensure
proper safety.