No. 2A201-519EN*A
39
8.1.3.2 Countermeasures
If a ground fault interrupter is to be installed, note the following points:
•
The sensitivity current should be 100 mA.
•
The ground fault interrupter should be noise proof.
(For example, Toshiba model NJV225F or equivalent)
It is desirable that the breaker be replaced with a Toshiba-recommended breaker to prevent
the leakage current problem described above.
Countermeasures against incorrect operation due to high-frequency elements have been
taken in the leakage detector of the recommended breaker, therefore the effects of the high-
frequency elements are eliminated.
The actual characteristics are shown in figure 8.1-3.
For the leakage alarm as well as for the breaker, investigate countermeasures to reduce
high-frequency electromagnetic radiation.
Since the 50-Hz element is small, if the high-frequency element is reduced, it becomes
possible to eliminate the problem without changing the sensitivity setting.
5000
1000
500
100
50
50
100
500
1K
10K
100K
Op
era
tion c
urren
t
(m
A)
Frequency (Hz)
Figure 8.1-3 Frequency characteristics of the sensitivity of the recommended
breaker (NJV225F) to electrical short circuits
