Electrical Connections; Primary Lead Connections; Ground Connections; Secondary Control Wiring - Siemens SDV7 Instruction Manual

14

Electrical connections

Primary lead connections

The primary leads must be routed to the
bushing terminals so as to maintain
adequate dielectric clearance between
different phase conductors and to ground.
Conductors must be supported so that the
circuit breaker bushings are not subjected to
excessive strains, both during normal
service and in the event of a short-circuit
condition. The leads should be sized to have
a capacity at least equal to the maximum
operating current of the circuit and within
the rating of the type SDV7 distribution
circuit breaker. Connections are to be made
to the bolted terminals of the bushings and
must be securely tightened to a clean,
bright surface to assure good contact.

Ground connections

Grounding pads on diagonally opposite
corners of the enclosure are provided for
connecting the cabinet to ground. The
grounding conductors should be at least 4/0
AWG conductor on each ground pad. A good
low-resistance ground is essential for
adequate protection and for proper
functioning of electronic components such
as protective relays. Connections to ground
pads must be made in such a manner that a
reliable ground connection is obtained.
Consult latest National Electrical Code® or
National Electric Safety Code® for ground
connection standards.
Hazardous voltages and high speed moving parts.
Will cause death, serious injury or property damage.
Do not work on energized equipment. Always de-energize and ground high-
voltage conductors before working on or near them. The user must adjust
the circuit breaker height to ensure compliance with safety codes for
electrical clearance.

Secondary control wiring

All secondary control wiring installed by the
factory is neatly routed and secured in
place. Complete all field connections in a
similar manner. Check that the protective
relay panel (if so equipped) clears any
additional wiring installed.
A conduit panel opening is provided in the
bottom of the relay and control
compartment for the connection of control
circuits. The control wires should be run
separately from high-voltage wiring to
prevent inductive coupling between them
and should be sized for full operating
current to avoid a drop in voltage below that
specified on the nameplate. All conduits
should be sealed off at their entrance to the
relay and control compartment.
Terminal blocks are provided inside the relay
and control compartment for the
connections necessary for the control wiring
and protective relay panel (if so equipped).
Terminal blocks for current transformer
wiring are located in the operator
compartment and wires can easily be routed
from the conduit panel opening in the relay
and control compartment to the current
transformer circuit terminal blocks in the
operator compartment. Consult the
connection diagrams for the location of
connection terminal points for each circuit.
Connection diagrams are provided with
each type SDV7 distribution circuit breaker
and will be found in the pocket inside the
relay and control compartment door.