Electrical Connection - Three-Phase Pumps, 11-22 Kw; Mains Switch; Protection Against Electric Shock - Indirect Contact; Additional Protection - Grundfos CRE Installation And Operating Instructions Manual

3.7 Electrical connection – three-phase pumps,
11-22 kW
The user or the installer is responsible for the
installation of the correct earthing and protection
according to valid national and local standards.
Caution
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.

3.7.1 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.

3.7.2 Protection against electric shock - indirect contact

The pump 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 is > 10 mA, these motors
must be connected to especially reliable/sturdy
Caution
earth connections.
The leakage current of the motor can be found in section
14.2 Leakage current
EN 50 178 and BS 7671 specify the following:
The pump must be stationary and installed permanently.
Furthermore, the pump must be connected permanently to the
electricity 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
area of 10 mm².
• Separate duplicate conductors each having a minimum cross-
sectional area of 4 mm².
• Duplicate (protective earth) conductors in a multicore cable.
One of the conductors may be the metallic armour or sheath of
the cable.
• A protective earth conductor contained in a cable conduit,
trunking or cable tray so forming a duplicate conductor.

3.7.3 Additional protection

If the pump is connected to an electric installation where an earth
leakage circuit breaker is used as additional protection, this
circuit 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
currents 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:
When an earth leakage circuit breaker is
selected, the total leakage current of all the
Note
electrical equipment in the installation must be
taken into account.
8
ELCB
The leakage current of the motor can be found in section
14.2 Leakage current.

3.7.4 Motor protection

The pump requires no external motor protection. The motor
incorporates thermal protection against slow overloading and
blocking.

3.7.5 Protection against mains voltage transients

The pump is protected against mains voltage transients in
accordance with EN 61 800-3.

3.7.6 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.
For maximum back-up fuse, see section 14.1 Supply voltage.
L1
ELCB
L2
L3
PE
Fig. 9 Example of a mains-connected pump with mains
switch, back-up fuses and additional protection
Fig. 10 Mains connection

3.7.7 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
approx. 5 seconds.
If a higher number of starts and stops is desired, the input for
external 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