Neutral Systems; Tt Network - Chauvin Arnoux C.A 6710 Notice De Fonctionnement

A
B
C
D
T
IMPORTANT PRECAUTION:
This demo case has been designed to simulate measurement on various types of electrical networks. It has not been
designed to recreate the electrical faults which may occur on these networks. Do not create short circuits between the
phase, neutral and earth.

TT network

3.1
Reminder:
This type of system is used in France, for example, in domestic electrical installation supplied from a public low-voltage distribution
network.
In a TT system, the neutral of the public transformer (electricity company) is connected to the ground and the earths of
the installation are connected to the ground.
Connections (see figure 2) :
Do not connect the neutral and the earth at the level of ref. A
The 1000 Ω resistance between terminals B and C must be shunted
Terminal D must be linked to earth T
Earth E must be connected to the earth bar of the building F
The ES earth can also be connected to the earth bar F to simulate a complex earth connection made up of earths in parallel.
Theoretical principle:
A fault current is closed off by the loop containing the earth connections of the earths and the neutral.
A residual differential device (RDD or RCD) cuts off the power when the nominal current of the RDD is reached.
The nominal current must be adapted to the value of R
The earths protected by the same differential or the earths simultaneously accessible must be connected to the same earth.

3. NEUTRAL SYSTEMS

E
Figure 2
so that R
earth
18
ES
x In < 50 V in dry conditions or 25 V in humid conditions.
earth
F