User's Manual

Surge Protective Devices
Installation, Operation and Maintenance Manual 14 Liebert SPDs SL-22085 Rev 5, 11/2009
Installation Instructions
All electrical connections shall be installed by a qualified (licensed) electrician. All wiring must comply with the National Electrical
Code (NEC) and applicable local codes.
National Electrical Code (NEC) Considerations
The National Electrical Code Article 240-21 details specific tap rules that should be considered before installation.
NEC 240.21 Location in Circuit. Over current protection shall be provided in each ungrounded circuit conductor and shall
be located at the point where the conductors receive their supply except as specified in 240.21(A) through (G). No conductor
supplied under the provisions of 240.21(A) through (G) shall supply another conductor under those provisions, except through
an over current protective device meeting the requirements of 240.4.
(A) Branch-Circuit Conductors. Branch-circuit tap conductors meeting the requirements specified in 210.19 shall be
permitted to have over current protection located as specified in that section.
(B) Feeder Taps. Conductors shall be permitted to be tapped, without over current protection at the tap, to a feeder as
specified in 240.21(B)(1) through (5).
(1) Taps Not Over 3 m (10 ft) Long. Where the length of the tap conductors does not exceed 3 m (10 ft) and the tap
conductors comply with all of the following:
(1) The Ampacity of the tap conductors (25 Amps in our case) is
a. Not less than the combined computed loads on the circuits supplied by the tap conductors, and
b. Not less than the rating of the device supplied by the tap conductors or not less than the rating of the over
current protective device at the termination of the tap conductors.
(2) The tap conductors do not extend beyond the switchboard, panelboard, disconnecting means, or control devices
they supply.
(3) Except at the point of connection to the feeder, the tap conductors are enclosed in a raceway, which shall extend
from the tap to the enclosure of an enclosed switchboard, panelboard, or control devices, or to the back of an
open switchboard.
(4) For field installations where the tap conductors leave the enclosure or vault in which the tap is made, the rating
of the over current device on the line side of the tap conductors shall not exceed 10 times the Ampacity of the
tap conductor.
(2) Taps Not Over 7.5 m (25 ft) Long. Where the length of the tap conductors does not exceed 7.5 m (25 ft) and the tap
conductors comply with all of the following:
(1) The Ampacity of the tap conductors is not less than one-third of the rating of the over current device protecting the
feeder conductors (75 Amp maximum in our case).
(2) The tap conductors terminate in a single circuit breaker or a single set of fuses that will limit the load to the
Ampacity of the tap conductors. This device shall be permitted to supply any number of additional over current
devices on its load side.
(3) The tap conductors are suitably protected from physical damage or are enclosed in a raceway.
(3) Taps Supplying a Transformer. Not Applicable
(4) Taps Over 7.5 m (25 ft) Long. Not Applicable
(5) Outside Taps of Unlimited Length. Not Applicable
Flexible liquid tight non-metallic conduit in lengths greater than six feet must be installed in accordance with NEC 351-27.
Liebert ACG Series (AccuGuide) — Type ACG
SPD Interconnect Assembly
Installation, Operation and Maintenance Manual 13 Liebert SPDs SL-22085 Rev 5, 11/2009
Surge Protective Devices
Connection
The Liebert ACG Series (AccuGuide) assembly is provided in standard lengths of 5, 8, 10, 12, 15, and 20 feet. Each end of the
assembly will include an additional five feet of #10, 8, 6, or 4 AWG pigtails for connection to the service and to the surge protective
device (SPD). Gauge of the pigtail is based on the SPD lug size. See chart below for units and acceptable wire ranges. An additional
10 gauge-grounding conductor is provided with the AccuGuide assembly for use as an equipment ground.
Liebert SI Series (Interceptor II) Acceptable Wire Range
All Units - No Disconnect #14 – 2/O
SI016-025 – With Disconnect #8 – 1/O
SI032-100 – With Disconnect #8 – 1/O
Conduit
The Liebert ACG Series (AccuGuide) assembly is sold without conduit. If conduit housing is required, the following conduit and
fitting sizes apply:
Equipment Performance
The ideal SPD installation locates the suppression as close to the protected bus as possible. This product was designed to address
those instances when a close installation is not possible. However, while the voltage drop experienced with an AccuGuide
assembly is significantly reduced, care should be taken to keep connection lengths to a minimum.
Each end of the AccuGuide assembly is shipped with five-foot pigtails. The length is offered as a worst-case need for the panel or
switchgear end (our SPD will be much less than 5 feet). We recommend cutting the pigtail to the shortest length possible.
No. of Conductors Conduit Size (in.)
1 Coax Cable, 1 GND 1
2 Coax Cable, 1 GND 1-1/4
3 Coax Cable, 1 GND 1-1/4
4 Coax Cable, 1 GND 1 1/4
5 Coax Cable, 1 GND 1 1/2
6 Coax Cable, 1 GND 1 1/2
7 Coax Cable, 1 GND 1 1/2
Caution: Pigtails must be supported if pulling AccuGuide assembly through conduit. Grip only the blue coaxial cable
body when pulling the assembly through conduit. Do not pull AccuGuide assembly using the pigtails or damage
may occur.
Liebert LM Series Acceptable Wire Range
All Units - No Disconnect #10 – #2
LM060-080 – With Disconnect #8 – 1/O
LM100-250 – With Disconnect #8 – 1/O