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All electrical connections should be installed by a qualified
(licensed) electrician only. All wiring must comply with the
National Electrical Code (NEC) and applicable local codes.
! !
VERIFY
THAT
CIRCUITS ARE DE-ENERGIZED AND
LOCKED OUT BEFORE MAKING
ELECTRICAL CONNECTIONS.
Voltage Ratings &
Power Source Configurations
Before making connections to the unit, verify that the unit
model number and nameplate voltage rating are appropriate
for connection to the intended power source. See Figure 2
for voltage rating applications with typical power source
configurations.
Surge Voltage Ratings – To obtain the suppression voltage
ratings (SVRs ), as obtained by Underwriters Laboratory,
Incorporated, in accordance with the Standard for
Safety, Surge Protective Devices (SPDs), Standard 1449,
Second Edition, dated August 15, 1996, marked on this
product, #8 AWG wire must be utilized to connect the
LM series to your facilities' power grid. Connections
made with conductors other that #8 AWG may result in
different SVRs.
Circuit Ampacity Limitations – This device has been
investigated by Underwriters Laboratories, Incorporated
to withstand, without exposing live circuits or
components on power sources, a voltage of two times
(2x) the device ratings, and fault currents of up to
300,000 AIC, as described in the Standard for Safety,
Surge Protective Devices (SPDs), Standard 1449,
Second Edition, dated August 15, 1996.
Installation, Operation
and Maintenance Manual
®
ELECTRICAL CONNECTIONS
DANGER
ALL
POWER
Parallel Connection
With parallel connection, the length of the wiring to the
surge protective device (SPD) unit must be minimized for
best performance. Wire lengths longer that 10 feet must be
avoided.
To reduce the wiring impedance to surge currents, the phase,
neutral
(if
required),
recommended to be twisted together and routed in the same
raceway (conduit). Avoid any sharp bends in the conductors.
Wire Sizing – With parallel connection, the size of the
wiring to the SPD unit is independent of the protected
circuit's ampacity. Suggested wire size of the product is
a number 8 gauge conductor minimum. Please reference
Figure 1. NEC Articles 280-21 and 22 require surge
arrestor connecting conductors to be at least #14 copper
or #12 aluminum.
Overcurrent Protection
practically no current under normal operation and only
conducts very short duration transient surge currents.
The Liebert SPD units contain UL approved internal
fusing to protect against device failure.
External overcurrent protection is not specifically
required by NEC Article 280 nor is it desired since it
impedes the performance of the surge protective device.
If fusing is required, please consult factory for
recommendations.
Disconnect Switch – SPD units must be connected to the
load side of the service disconnect, or load side of a
protected circuit's disconnecting means.
performance, the SPD unit must be located very close to
the circuit to be protected and minimum interconnecting
wiring used.
A disconnect switch is sometimes used to facilitate
servicing the SPD unit. However, use of a disconnect
switch for the SPD unit impedes the transient surge
suppressing performance of the unit.
transient surge suppressor performance, no disconnect
switch is recommended. If a disconnect switch is used,
the location and wiring of the switch and SPD unit
should minimize the interconnecting wiring (see Figure
4).
Models with a "R" suffix are equipped with an internal
disconnect switch, which can be used to de-energize the
unit's transient surge suppressing components for
servicing.
- 5 -
Surge
Suppression
Systems
(see Figures 3 and 4)
and
ground
conductors
– The SPD unit conducts
For best
For maximum
LM Series
Rev 0, 5/99
are
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