METREL MI 3399, Инструкция с упражнениями

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Electrical Installation Safety Trainer AD 1 - MI 3399
72
𝑰
𝑷𝑭𝑪
=
𝑼
𝑵
𝒁
𝑴𝑬𝑨𝑺𝑼𝑹𝑬𝑫
where:
U
N
– nominal value, determined according to the measured voltage (U
L-PE
).
In a 1-phase TN system the maximum allowed impedance result for a 6A gG type fuse
with 400ms trip-out time is
4,6
Ω
whereas in a 3-phase TN system the maximum
allowed impedance result for a 6A B type fuse with 200ms trip-out time is 7,3
Ω
6
.
As seen from both screens the impedance and I
PSC
are both within limits and the tests
are marked as passed.
Expected results with a simulated error
During the test we add an error on the PE conductor by enabling switch S20 in the
Application Trainer. Toggling this switch introduces additional resistance on the PE
conductor on a 1-phase TN earthing system.
Figure 2-20: Simulated error on PE conductor in a 1-phase TN system
6
See chapter 1.4 Ensurance of Safety for more details on fuse and RCD trip-out times and impedances.
E
xer
ci
ses
S
w
itch
Function Site of error ON OFF
S15 R LOW / IMD
IT F3/1
PE outlet
> 20
Ω
< 1
Ω
S16 ISFL / IMD
IT F3/2
ISFL approx. 6 mA (@ 230 V)
approx. 3 mA (@ 115 V)
< 1.3 mA
S17 R LOW IT PE ref.
approx. 3.3 Ω < 1 Ω
S18 R LOW
TN/TT F1/4
PE light
> 20
Ω < 1 Ω
S19 R LOW / Z LOOP
TN/TT F1/2
PE outlet (3-ph.)
approx. 3.4 Ω < 1 Ω
S20 R LOW / Z LOOP
TN/TT F2/2
PE outlet
> 2.3
Ω < 2 Ω
S21 R LOW MPE / PE Gas
approx. 2.2 Ω < 1 Ω
S22 R LOW MPE / PE Heat inst.
approx. 3.3 Ω < 1 Ω
P
E
C
o
n
n
e
c
tio
n