User manual - METER SUR-457
4.3.
CONNECTION METHOD
Caution
- Installation should be conducted by qualified personnel . During installation all
available safety requirements should be considered. The fitter is responsible for
executing the installation according to this manual, local safety and EMC
regulations.
- The unit is not equipped with an internal fuse or power supply circuit breaker.
Because of this an external time-delay cut-out fuse with a small nominal current
value must be used (recommended bipolar, max. 2A) and a power supply circuit-
breaker located near the unit. In the case of using a monopolar fuse it must be
mounted on the phase cable (L).
- The power supply network cable diameter must be selected in such a way that in
the case of a short circuit of the cable from the side of the unit the cable shall be
protected against destruction with an electrical installation fuse.
- Wiring must meet appropriate standards and local regulations and laws.
- In order to secure against accidental short circuit the connection cables must be
terminated with appropriate insulated cable tips.
- Tighten the clamping screws. The recommended tightening torque is 0.5 Nm.
Loose screws can cause fire or defective operation. Over tightening can lead to
damaging the connections inside the units and breaking the thread.
- In the case of the unit being fitted with separable clamps they should be inserted
into appropriate connectors in the unit, even if they are not used for any
connections.
- Unused terminals (marked as n.c.) must not be used for connecting any
connecting cables (e.g. as bridges), because this can cause damage to the
equipment or electric shock.
- If the unit is equipped with housing, covers and sealing to, protecting against
water intrusion, pay special attention to their correct tightening or clamping. In the
case of any doubt consider using additional preventive measures (covers, roofing,
seals, etc.). Carelessly executed assembly can increase the risk of electric shock.
- After the installation is completed do not touch the unit’s connections when it is
switched on, because it carries the risk of electrical shock.
Due to possible significant interference in industrial installations appropriate measures
assuring correct operation of the unit must be applied. To avoid the unit of improper
indications keep recommendations listed below.
–
Avoid running signal cables and transmission cables together with power supply cables
and cables controlling inductive loads (e.g. contactors). Such cables should cross at
a right angle.
–
Contactor coils and inductive loads should be equipped with interference protection
systems, e.g. RC-type.
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