METREL MI 3399, Инструкция с упражнениями

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Electrical Installation Safety Trainer AD 1 - MI 3399
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Figure 2-52: Total earthing measurement (3 wires)
– standard method
Notes:

This method enables accurate results from 0
Ω up to several 1000 Ω.

This method is not suitable for very large or connected earthing systems because test
probes must be then placed at very long distances from the measured object.

If measuring individual earthing resistances, the measured rod (point) must be
disconnected from the system.

In TN systems incoming PE (PEN) conductor must be disconnected!
Figure 2-53: Selective earthing measurement
– standard method
𝐼
𝑔𝑒𝑛
= 𝐼
𝑅𝐸2
The equation above indicates that the test current flows only through the partial resistance
R
E2
. In this case only R
E2
is measured.
Notes:

Accurate results from 0
Ω, no limitation regarding number of points.

Not suitable for very large or connected earthing systems because test probes must
be then placed at very long distances from the measured object.