Other Connections; Electrical Connection - Three-Phase Motors; Mains Switch; Protection Against Electric Shock - Indirect Contact - Grundfos MGE 71 Installation And Operating Instructions Manual

5.8 Other connections

The connection terminals of external potential-free contacts for
start/stop, external setpoint signal and relay signal are shown in
fig. 8.
If no external on/off switch is connected, short-circuit
Note
terminals 2 and 3 using a short wire.
As a precaution, the wires to be connected to the
following connection groups must be separated from
Caution
each other by reinforced insulation in their entire
lengths:
• Inputs (external start/stop and setpoint signal, terminals 2-6).
All inputs (group 1) are internally separated from the
mains-conducting parts by reinforced insulation and
galvanically separated from other circuits.
All control terminals are supplied by protective extra-low
voltage (PELV), thus ensuring protection against electric
shock.
• Output (signal relay, terminals NC, C, NO).
The output (group 2) is galvanically separated from other
circuits. Therefore, the supply voltage or protective extra-low
voltage can be connected to the output as desired.
• Mains supply (terminals N, PE, L).
A galvanically safe separation must fulfil the requirements for
reinforced insulation including creepage distances and
clearances specified in EN 61800-5-1.
MGE 71 and MGE 80
NC C NO N PE L
STOP
RUN
0/4-20 mA 0-10 V
10K
6 5 4 3 2
Change of direction
of rotation
Fig. 8 Connection terminals
6: GND (frame)
5: +10 V
4: Setpoint input
3: GND (frame)
2: Start/stop

6. Electrical connection - three-phase motors

The user or the installer is responsible for the
installation of the correct earthing and protection
Caution
according to valid national and local standards. All
operations must be carried out by a qualified
electrician.
Warning
All electric supply circuits must be interrupted before
working in the motor terminal box.
Warning
Never make any connections in the motor terminal
box unless the power supply has been switched off
for at least 5 minutes.

6.1 Mains switch

The motor must be connected to an external all-pole mains switch
with a contact separation of at least 3 mm in each pole according
to IEC 364.

6.2 Protection against electric shock - indirect contact

Warning
The motor must be earthed and protected against
indirect contact in accordance with national
regulations.
Protective earth conductors must always have a yellow/green
(PE) or yellow/green/blue (PEN) colour marking.
As the leakage current of 4 kW to 7.5 kW motors is >
Caution
3.5 mA, these motors must be connected to
especially reliable/sturdy earth connections.
The leakage current of the motor can be found in section
12.2 Leakage current.
EN 50178 and BS 7671 specify the following:
Leakage current > 3.5 mA
The motor must be stationary and installed permanently.
Furthermore, it must be connected permanently to the power
supply.
• The earth connection must be carried out as duplicate
conductors.
Leakage current > 10 mA
If the installation includes several mains-connected units and the
total leakage may be > 10 mA, the demands on the earth
connection are tightened.
The motor must be stationary and installed permanently.
Furthermore, it must be connected permanently to the power
supply.
In addition, tightened precautions as regards earth connection
must be observed.
One of the following installation examples must be used:
• A single protective earth conductor having a cross-sectional
2
area of 10 mm .
• Separate duplicate conductors each having a minimum
cross-sectional area of 4 mm
• A protective earth conductor contained in a cable conduit,
trunking or cable tray so forming a duplicate conductor.
2
.
5