Electrical Connection - Three-Phase Pumps; Mains Switch; Protection Against Electric Shock - Indirect Contact; Additional Protection - Grundfos LME Series Installation And Operating Instructions Manual

2.2 Electrical connection – three-phase pumps
Note: The user or the installer is responsible for the installation of
the correct earthing and protection according to valid national and
local standards. All operations must be carried out by a qualified
electrician.
Never make any connections in the pump terminal
box unless the electricity supply has been switched
off for at least 5 minutes.

2.2.1 Mains switch

The pump 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.
2.2.2 Protection against electric shock – indirect contact
The pump must be earthed and protected against
indirect contact in accordance with national regula-
tions.
Protective earth conductors must always have a yellow/green
(PE) or yellow/green/blue (PEN) colour marking.
Note: As the leakage current of 4 kW to 7.5 kW motors is
> 3.5 mA, these motors must be connected to especially
reliable/sturdy earth connections.
The leakage current of the individual motor size can be found in
section 13.2 Leakage current.
EN 50 178 and BS 7671 specify the following:
Leakage current > 3.5 mA:
The pump must be stationary and installed permanently. Further-
more, the pump must be connected permanently to the electricity
supply or may be connected via an industrial type of plug (CEE).
The plug must comply with EN 60 309 or IEC 309.
• The earth connection must be carried out as duplicate conduc-
tors.

2.2.3 Additional protection

If the pump is connected to an electric installation where an earth
leakage circuit breaker is used as additional protection, this cir-
cuit breaker must be of the type:
• which is suitable for handling leakage currents and cutting-in
with short pulse-shaped leakage.
• which trips out when alternating fault currents and fault cur-
rents with DC content, i.e. pulsating DC and smooth DC fault
currents, occur.
For these pumps an earth leakage circuit breaker type B must be
used.
This circuit breaker must be marked with the following symbols:
Note: When an earth leakage circuit breaker is selected, the total
leakage current of all the electrical equipment in the installation
must be taken into account.
The leakage current of the pump can be found in section
13.2 Leakage current.

2.2.4 Motor protection

The pump requires no external motor protection. The motor incor-
porates thermal protection against slow overloading and blocking
(IEC 34-11: TP 211).

2.2.5 Overvoltage protection

The pump is overvoltage-protected through built-in varistors be-
tween the phases and between phases and earth.
6
ELCB

2.2.6 Supply voltage

3 x 380-415 V ±10%, 50/60 Hz, PE.
The supply voltage and frequency are marked on the pump
nameplate. Please make sure that the motor is suitable for the
electricity supply on which it will be used.
The wires in the pump terminal box must be as short as possible.
Excepted from this is the protective earth conductor which must
be so long that it is the last one to be disconnected in case the
cable is inadvertently pulled out of the cable entry.
Figure 5 shows an example of a mains-connected pump with
mains switch, back-up fuses and additional protection.
Fig. 5
MGE 90 to MGE 132
Max. 16/32 A
L1
ELCB
L2
L3
PE
Actual mains connection is shown in figs. 6 and 7.
Fig. 6
MGE 90 and MGE 100
L1
L2
L3
Fig. 7
MGE 112 and MGE 132
L1
L2
L3

2.2.7 Start/stop of pump

The number of starts and stops via the mains voltage must not
exceed 4 times per hour.
When the pump is switched on via the mains, it will start after ap-
prox. 5 seconds.
If a higher number of starts and stops is desired, the input for ex-
ternal start/stop must be used when starting/stopping the pump.
When the pump is started/stopped via an external on/off switch, it
will start immediately.
L1
L2
L3
L1
L2
L3
L1
L2
L3