S&C PMX Guide

Instructions for Installation
S&C PMX™Modular Metal-Enclosed Switchgear
Outdoor Distribution (13.8 kV and 25 kV)
S&C ELECTRIC COMPANY
Specialists in Electric Power Switching and Protection
Instruction Sheet 627-500
April 11, 2005 ©2005
Supersedes Instruction Sheet 627-500 dated 1-19-04
Section Page Section Page
INTRODUCTION
General . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .2
Qualified Persons . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .2
Read this Instruction Sheet . . . . . . . . . . . . . . . . . . . . .3
Retain this Instruction Sheet . . . . . . . . . . . . . . . . . . . .3
Proper Application . . . . . . . . . . . . . . . . . . . . . . . . . . . . .3
Warranty. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .4
SAFETY INFORMATION
Understanding Safety-Alert Messages. . . . . . . . . . . . .5
Following Safety Instructions. . . . . . . . . . . . . . . . . . . .5
Replacement Instructions and Labels . . . . . . . . . . . .5
Enclosure Security . . . . . . . . . . . . . . . . . . . . . . . . . . . .6
Access Control. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .6
Location of Safety Labels . . . . . . . . . . . . . . . . . . . . . . .7
INSPECTION AND HANDLING
Packing . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8
Inspection . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .8
Handling . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .9
BATTERY STORAGE
Charging the Battery . . . . . . . . . . . . . . . . . . . . . . . . . . 10
INSTALLATION
Access to Interior . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12
Placement. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13
Cable Terminations . . . . . . . . . . . . . . . . . . . . . . . . . . . 16
Preparing for Service . . . . . . . . . . . . . . . . . . . . . . . . . . 17
ADDITIONS TO EXISTING PMX ASSEMBLIES . . . . . . .29
COMPONENTS
Mini-Rupter® Switch . . . . . . . . . . . . . . . . . . . . . . . . . . 31
Power Fuses. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 31
Switch Operator—Type PM . . . . . . . . . . . . . . . . . . . 31
Micro-AT Source-Transfer Control . . . . . . . . . . . . . 31
Voltage Sensor . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .32
Current Sensor . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .32
INTERLOCKS
Mechanical Interlocks . . . . . . . . . . . . . . . . . . . . . . . . .33
Key Interlocks . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .33
DIELECTRIC TESTING . . . . . . . . . . . . . . . . . . . . . . . . . . . . 34
MAINTENANCE
Enclosure Finish . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .35
SPECIFICATIONS
Optional Features . . . . . . . . . . . . . . . . . . . . . . . . . . . . 37
TABLE OF CONTENTS

627-500 2
INTRODUCTION
General The following instructions are for installation of manual or power-operated S&C PMX
Modular Metal-Enclosed Switchgear rated 13.8 kV or 25 kV.
An assembly of PMX Switchgear may incorporate many types of components, such as
interrupter switches, power fuses, switch operators, a source-transfer control, voltage
sensors, current sensors, meters, etc., depending on user requirements.
Instructions for operation of each S&C component are provided in a separate S&C
instruction sheet. For each switchgear assembly, the applicable instruction sheets, drawings,
and wiring diagrams are bound in a folder entitled “Instruction Manual.” This instruction
manual is located in a holder inside the appropriately marked switchgear-module door.
Qualified Persons ÇCAUTION
The equipment covered by this publication must be selected for a specific application
and it must be installed, operated, and maintained by qualified persons who are
thoroughly trained and who understand any hazards that may be involved. This
publication is written only for such qualified persons and is not intended to be a
substitute for adequate training and experience in safety procedures for this type of
equipment.
Each assembly of S&C PMX Modular Metal-Enclosed Switchgear is provided with an
“INSTALLATION AND OPERATION INFORMATION KIT” located in the holder inside the
switchgear-module door on which the label “Installation and Operation Information Kit
Inside This Bay” is affixed. The “INSTALLATION AND OPERATION INFORMATION KIT”
includes applicable instruction sheets covering installation of the switchgear assembly
and operation of components, plus drawings and wiring diagrams. All personnel involved
with installation and operation of the switchgear assembly should be thoroughly familiar
with the contents of the “INSTALLATION AND OPERATION INFORMATION KIT.”
This equipment has been provided with comprehensive access control and operating
features to minimize hazards. However, since this equipment contains high voltage,
there are hazards inherently present such that the following precautions should
be observed at all times. FAILURE TO OBSERVE THESE PRECAUTIONS MAY
RESULT IN SERIOUS INJURY OR DEATH.
1. Padlocks must be installed and secured on all door handles and manual switch
operating handles at all times unless a switch is being operated.
2. Snaplocks must be in place and the keys must be removed.
3. Key interlocks (if applicable) must be in place. Check the operating sequence of key
interlocks to verify proper sequencing. After the switchgear is installed, destroy all
duplicate keys or make them accessible only to authorized persons so that the key
interlock scheme will not be compromised. Key interlocks are not security locks.
4. Mechanical cable interlocks are provided to prevent access to fuses unless the switch
is open and to prevent operation of stored-energy switch operators when the module
door is open. Do not attempt to operate any switch when the enclosure door is open.
Periodically, verify that these interlocks are functional. Refer to the instructions
under “INTERLOCKS” on page 33.
5. Do not apply any undue force to any handle when attempting to open or close a door
or cover. The use of undue force may damage the handle or latching mechanism, or
an interlock mechanism may be jammed. Do not attempt to close doors in an effort to
reset interlocks. Instead, follow the instructions under “INTERLOCKS” on page 33.

627-500
3
INTRODUCTION
ÇCAUTION—Continued
6. Do not remove or obscure any of the “CAUTION,” “DANGER,” or other precautionary
signs and labels.
7. Make certain hanging barriers are in place unless work is being performed inside a
module.
8. Make certain all switchgear modules are properly grounded.
9. Make certain fuses are disconnected from all power sources (including backfeed)
before being inspected or replaced.
10. Test for voltage and install suitable grounding equipment before touching any device
that is to be inspected, serviced, or repaired. Voltage testers suitable for this purpose
are available from S&C.
11. Always assu me both sets of power terminals on switch, fuse, or terminal connections
are energized unless proved otherwise by test or visual evidence.
12. Disconnect all voltage transformers and voltage sensors when external voltage is
used to test any secondary-side wiring or when heaters are energized for temporary
storage. Do not disconnect voltage limiters from voltage sensors when the switchgear
is energized.
Read this
Instruction Sheet
Read this instruction sheet thoroughly and carefully before installing or operating your
S&C PMX Modular Metal-Enclosed Switchgear. Familiarize yourself with “SAFETY
INFORMATION” on pages 5 through 7.
Retain this
Instruction Sheet
This instruction sheet is a permanent part of your S&C PMX Modular Metal-Enclosed
Switchgear. Designate a location where you can easily retrieve and refer to this
publication.
Proper Application ÇCAUTION
The equipment in this publication must be selected for a specific application. The
application must be within the ratings of the equipment. Ratings for this gear are listed
on a ratings label located on the outside of the switchgear.

627-500 4
INTRODUCTION
Warranty The warranty and/or obligations described in S&C’s standard conditions of sale, as set
forth in Price Sheet 150, plus any special warranty provisions, as set forth in the applicable
product-line specification bulletin, are exclusive. The remedies provided in the former for
breach of these warranties shall constitute immediate purchaser’s or end user’s exclusive
remedy and a fulfillment of all seller’s liability. In no event shall seller’s liability to immedi-
ate purchaser or end user exceed the price of the specific product which gives rise to imme-
diate purchaser’s or end user’s claim. All other warranties whether express or implied or
arising by operation of law, course of dealing, usage of trade or otherwise, are excluded.
The only warranties are those stated in Price Sheet 150, and THERE ARE NO EXPRESS
OR IMPLIED WARRANTIES OF MERCHANTABILITY OR FITNESS FOR A PARTICULAR
PURPOSE. ANY EXPRESS WARRANTY OR OTHER OBLIGATION PROVIDED IN PRICE
SHEET 150 IS GRANTED ONLY TO THE IMMEDIATE PURCHASER AND END USER, AS
DEFINED THEREIN. OTHER THAN AN END USER, NO REMOTE PURCHASER MAY
RELY ON ANY AFFIRMATION OF FACT OR PROMISE THAT RELATES TO THE GOODS
DESCRIBED HEREIN, ANY DESCRIPTION THAT RELATES TO THE GOODS, OR ANY
REMEDIAL PROMISE INCLUDED IN PRICE SHEET 150.
The seller’s warranties do not apply to major components not of S&C manufacture, such
as surge arresters, current-limiting fuses, instrument transformers, relays and meters,
low-voltage circuit breakers, remote terminal units, and terminators. However, seller
will assign to immediate purchaser or end user all manufacturers’ warranties that apply
to such components.

627-500
5
SAFETY INFORMATION
Understanding
Safety-Alert
Messages
There are several types of safety-alert messages which may appear throughout this
instr uction sheet as well as on labels and tags attached to the PM X Switchgear. Familiarize
yourself with these types of messages and the importance of the various signal words,
as explained below.
ÇDANGER
“DANGER” identifies the most serious and immediate hazards which will likely
result in serious personal injury or death if instructions, including recommended
precautions, are not followed.
ÇWARNING
“WARNING” identifies hazards or unsafe practices which can result in serious
personal injury or death if instructions, including recommended precautions, are
not followed.
ÇCAUTION
“CAUTION” identifies hazards or unsafe practices which can result in minor personal
injury or product or property damage if instructions, including recommended
precautions, are not followed.
NOTICE
“NOTICE” identifies important procedures or requirements that, if not followed, can
result in product or property damage if instructions are not followed.
Following Safety
Instructions
If you do not understand any portion of this instruction sheet and need assistance, contact
your nearest S&C Sales Office or S&C Authorized Distributor. Their telephone numbers
are listed on S&C’s website www.sandc.com. Or call S&C Headquarters at [phone];
in Canada, call S&C Electric Canada Ltd. at [phone].
NOTICE
Thoroughly and carefully read this
instruction sheet before installing your
S&C PMX Modular Metal-Enclosed
Switchgear.
Replacement
Instructions and
Labels
If you need additional copies of this instruction sheet, contact your nearest S&C Sales
Office, S&C Authorized Distributor; S&C Headquarters, or S&C Electric Canada Ltd.
It is important that any missing, damaged, or faded labels on the equipment be replaced
immediately. Replacement labels are available by contacting your nearest S&C Sales Office,
S&C Authorized Distributor, S&C Headquarters, or S&C Electric Canada Ltd.

627-500 6
Enclosure Security S&C PMX Switchgear incorporates many provisions to minimize hazards to qualified
persons and to the general public. Each module is fabricated from 11-gauge steel sheet and
is free-standing, and self-supporting. There are always double walls between adjoining
modules. Provisions for future bus extension are closed with a panel that is secured
internally.
Doors are constructed of 11-gauge hot-rolled, pickled and oiled steel sheet. Door-edge
flanges overlap with door-opening flanges and are formed to create a mechanical maze
that guards against water entry and discourages tampering or insertion of foreign objects,
but allows ventilation to help keep the enclosure interior dry. Each door is equipped with
a door handle. The door handle is padlockable and incorporates a hood to protect the
padlock shackle from tampering.
Access Control Access is from the front and rear only. Doors providing access to power fuses are mechan-
ically or key interlocked with the associated interrupter switch. Doors and hinged-bolted
panels providing access to high-voltage components are provided with flush-mounted
key-operated snaplocks and have provisions for padlocking. In addition, the hinged-bolted
panels are secured by a pentahead bolt provided with a protective hood, midway between
the top and bottom of the panel. Hex bolts are provided to secure the door near the top
and bottom.
SAFETY INFORMATION

627-500
7
Location of Safety Labels
Reorder Information for Safety Labels
Location Safety Alert Message Description Number
AÇCAUTION High Voltage—Keep Out G-4900R2
BÇCAUTION All Bolts Must Be Tightened G-9055
CÇDANGER Danger—High Voltage—Keep Out G-6500
DÇDANGER Danger—Switches May Be Energized By Backfeed G-6501
EÇDANGER Danger—Fuses May Be Energized By Backfeed G-6502
SAFETY INFORMATION
B
A
D
E
C

627-500 8
INSPECTION AND HANDLING
Packing
Each module is fastened to its own wooden
skid. Fuses, end-fittings, and splice-plate kits
are packaged separately.
At the first opportunity, remove all packing
materials (cardboard, paper, foam padding,
etc.) from the outside of the module. This will
prevent the finish from being damaged by
rainwater absorbed by the packing materials
and will also prevent wind-induced abrasion
from loose cardboard.
Inspection
Examine the shipment for external evidence
of damage as soon after receipt as possible,
preferably before removal from the carrier’s
conveyance. Check the bill of lading to make
sure that all shipping skids, crates, and
containers listed thereon are present.
If there is visible loss and/or damage:
1. Notify the delivering carrier immediately.
2. Ask for carrier inspection.
3. Note condition of shipment on all copies of
the delivery receipt.
4. File a claim with the carrier.
If concealed damage is discovered:
1. Notify the delivering carrier within 15 days
of receipt of shipment.
2. Ask for a carrier inspection.
3. File a claim with the carrier.
Also, notify S&C Electric Company in all
instances of loss and/or damage.

627-500
9
INSPECTION AND HANDLING
Handling
ÇWARNING
When handling PMX Switchgear with
an overhead hoist, observe standard
lifting practices as well as the general
instructions below. Failure to follow
these precautions can result in
serious personal injury or equipment
damage.
Step 1
Make sure that the lifting tabs are securely
bolted to the module before lifting it.
Step 2
Use 6-foot or longer hoist slings of equal length
to prevent overstressing the enclosure during
lifting.
Step 3
Arrange the hoist slings so as to distribute the
lifting forces equally between the lifting tabs.
See Figure 1.
Step 4
Avoid sudden starts and stops.
Figure 1. Hoisting arrangements.
See Detail A
Use timber as shown if the
lifting angle is less than 60°
from horizontal
Detail A
60° MIN.

627-500 10
BATTERY STORAGE
NOTICE
Remote supervisory modules of PMX Switchgear furnished with a battery charger and battery packs should preferably
be installed and energized immediately. If the modules cannot be installed immediately, store them in a clean, cool,
dry room, or remove the battery packs and store them in a cool, dry place. See S&C Instruction Sheet 669-515 for
instructions on removing the battery packs. Storing the battery packs at high temperatures will reduce their
operating life.
If the battery packs are not removed while the gear is in storage, make sure the power on/off switch on the battery
charger is in the ‘‘OFF” position. See Figure 2. The power will be drained from the battery packs if the switch
is in the “ON” position.
If the gear is not placed in service by the date shown on the tag attached to the switch operator containing the
battery packs, the battery packs must be charged as instructed on page 11. The battery packs will be damaged if
allowed to discharge completely.
Remote supervisory modules of PMX Switchgear may
include an S&C Battery Charger and battery packs. When
furnished, the battery charger and battery packs are
installed in the switch operator.
Figure 2. Interior view of Type PM Switch Operator showing battery packs and battery charger.
Local/remote selector switch
Switch control
Battery packs
Terminals for connec-
tion of 120-volt ac power
source when charging
battery
Battery charger
Open/close push buttons
Battery-charger input selec-
tor switch for choice of ac
power input from “EXTERNAL
SOURCE” or “VOLTAGE-SEN-
SOR SOURCE”
Power on/off switch must
be in “OFF” position to avoid
draining battery if stored in
switch operator
Terminals for testing
battery

627-500
11
BATTERY STORAGE
Charging the Battery
If the PMX Switchgear has not been placed in service
by the date shown on the tag attached to the switch
operator containing the battery, the battery charger must
be connected to a transformer-isolated 120-volt ac power
source to charge the two 12-volt dc battery packs. See
Figure 2. To connect a 120-volt ac power source to the
battery charger, proceed as follows:
1. Open the switch operator door as described under
“Access to Interior” on page 12.
2. Make sure that the power on/off switch on the battery
charger is in the “OFF” position.
3. Using a voltmeter, check the open-circuit voltage of each
battery pack by placing the probes on the appropriate
“1” and “2” terminals on the battery charger. One set of
terminals is provided for each battery pack. See Fig-
ure 2.
a. If the open-circuit voltage of either battery pack is
less than 10 volts dc, both battery packs must be
replaced. Refer to S&C Instruction Sheet 669-515 for
instructions on replacing the battery packs. Then
proceed to Step 7 below.
b. If the open-circuit voltage of each battery pack is 10
volts dc or greater, continue with Step 4 below.
4. Place the battery-charger input selector switch in the
“EXTERNAL SOURCE” position.
5. Connect a transformer-isolated 120-volt ac power source
to the two terminals marked “EXT/AC” on the battery
charger. Place the power on/off switch on the battery
charger in the “ON” position and charge the battery for
24 hours.
6. After charging the battery, place the power on/off switch
on the battery charger in the “OFF” position. Then
disconnect the 120-volt ac power source, and place the
battery-charger input selector switch in the “VOLTAGE-
SENSOR SOURCE” position.
7. Secure the switch operator door.

627-500 12
INSTALLATION
Access to Interior
To Open Doors and Panels
Enclosure Door
Step 1
The non-removable manual handle rotates for
door opening. As illustrated in Figure 3, open
the door by moving the handle clockwise 90°
until door is unlatched.
Step 2
Pull the door open and secure it with the
doorstop.
ÇCAUTION
Do not apply undue force to any door
handle when attempting to open a door.
The use of undue force may damage the
door handle and latching mechanism,
or an interlock may be jammed. Verify
that the snap locks are unlocked and
that opening the door is in the sequence
dictated above.
Rear Access Panel
Step 3
The rear access panel employs a pentahead/
hexhead bolting scheme. There are three
bolts located on the panel: Two hexhead
bolts located each at the top and the bottom,
and a pentahead bolt in the middle covered
by a protective hood; see Figure 4. Using the
appropriate socket wrench or tool, loosen and
remove the bolts by rotating the tool counter-
clockwise.
Step 4
Pull the panel open and secure it with the
doorstop.
Figure 3. Non-removable manual handle—requires rota-
tion of 90° to open or close door. Handle is padlockable. A
snaplock is also pictured.
Figure 4. Pentahead bolts secure the rear access panel.
Snap lock
Rotate handle
90° to open

627-500
13
INSTALLATION
To Close Doors and Panels
Enclosure Door
Step 5
Release the doorstop, and push and hold the
door closed. Then rotate the handle counter
clockwise to engage the latch points. See
Figure 3.
Step 6
Pull outward on the handle cover to verify
that the door has latched securely and insert a
padlock into the hasp.
Rear Access Panels
Step 7
Release the doorstop and tighten the three bolts
by rotating the wrench, or other appropriate
tool, clockwise until the bolts are sufficiently
tight.
Step 8
Pull outward on the access panel to verify that
the door has latched.
Placement
Step 9
Transport the switchgear to the installation
site observing the precautions given under
“Handling” on page 9.
Step 10
At the installation site, remove all the separately
packaged components, which were shipped
within the module, and set them aside.
Step 11
Each module of an assembly is identified by a
number on the front of the module See Figure 5.
Proper positioning of the module is indicated
on the anchor-bolt plan of the “CDA” drawing,
enclosed in the waterproof envelope labeled
“Instruction Manual.” Figure 5. Location of module identification.

627-500 14
INSTALLATION
When assembling PMX Switchgear, the
module having working clearance most affected
by adjacent walls should be placed first.
Unbolt the module from its skid and
lift observing the precautions given under
“Handling” on page 9. Align the channel base
so that it is centered on and square with the
anchor bolts.
Step 12
Be sure to obtain a weather-tight seal between
modules by applying a single thickness of
adhesive-backed foam gasketing tape (provided)
around exposed edges and roof section between
adjoining modules. See Figure 6.
Step 13
Level each module using metal shims as
required. Secure each module to the pad using
the anchor clips and anchor bolt nuts provided.
See Figure 7. Securely tighten the nuts. Make
sure the module doors and panels open and
close without binding. Binding indicates
enclosure distortion which must be corrected
by additional shimming.
Figure 6. Apply gasketing tape ¹⁄₈ inch from edge.
Figure 7. Installing anchor clips and nuts.

627-500
15
INSTALLATION
Step 14
Apply resilient grout at the bottom of each
module to prevent entry of rodents, insects, or
weeds. It is recommended that the grouting be
recessed sufficiently from the exterior exposure
to permit caulking with a weatherproof
compound, applied with a standard caulking
gun. A room-temperature vulcanizing (RTV)
silicone rubber compound is recommended.
Step 15
On multi-module assemblies shipped in
individual modules, align, level, center, check
door operation, grout, and caulk succeeding
modules in turn, and join modules with the
¹⁄₂–13 galvanized bolts provided. The bolts
may be easily pressed through the gasketing
tape. Do not attempt to draw misaligned
modules together with these bolts. See
Figure 8.
Figure 8. Alignment of PMX Switchgear modules.
This
Not this!

627-500 16
INSTALLATION
Figure 10. Sliding off roof section.
Figure 9. Removing bolts for roof section.
Cable Terminations
NOTICE
The roof is heavy. At least two line crew
are needed to remove the roof.
Step 16
For each module, remove the ¹⁄₂ 13 hex-head
stainless-steel cap screws, lockwashers, and
flat washers that attach the roof section to
the module. See Figure 9. Each roof section
will have two capscrews, two lockwashers,
and two flat washers. In order to remove the
roof, grasp with both hands and pull forward
until it is stopped by the two neoprene rollers.
Then, push down on the roof so that the side
channels clear the rollers. Next, continue to
pull the roof forward—with the help of the
second person—until the roof section is clear
of the switchgear. See Figure 10.
Location of bolts for removing
roof sections
Step 17
Make up the cable terminations. Terminal
pads accommodate one or, optionally, two
conductors per phase up to 750 kc mil.
Step 18
Slide the roof section back into position the
same way it was removed,and securely tighten
the bolts.
Neoprene
rollers

627-500
17
INSTALLATION
Preparing for Service
Step 19
The bus construction in PMX Switchgear is
typically aluminum, as are the terminal pads
of components. Such connections employ
Belleville (formed spring-steel) washers. See
Figure 11. Check these connections, but do not
tighten factory-made connections employing
Belleville washers unless they are visibly loose;
they have been correctly torqued to 50 foot-
pounds at the factory.
NOTE: For modules furnished with copper
bus, silver-to-silver connections are provided.
These connections employ brass flat washers
rather than Belleville washers and should
be torqued to 35 foot-pounds since they may
have loosened during shipment. Check bus
connections and, where necessary, correctly
tighten the connecting hardware.
NOTE: For modules employing enhanced
fuse handling construction, do not attempt to
remove the fuse access panel. Follow Steps 3
and 4 on page 12 to remove the rear access panel.
Also remove the hanging barrier. The main bus
can now be accessed.
For inter-module splices in the main bus
and ground bus, splice-plate kits have been
provided. These kits contain splice plates, bolts,
nuts, washers, a sheet abrasive paper, a tube of
Penetrox® A compound, and instructions. For
modules furnished with aluminum bus, both bus
ends and splice-plates have been pre-abraded
and coated with a thin layer of oxidation-
inhibiting grease at the factory.
Figure 11. Main bus with Belleville washers (if applicable).

627-500 18
INSTALLATION
Figure 12. Grommets on the through-bushings.
To ensure the highest quality joints, mating
surfaces of aluminum bus ends and splice
plates should be re-abraded with the abrasive
paper provided and immediately coated with
a uniform layer of Penetrox A, just prior to
making bolted connections.
NOTE: For copper main bus and ground
bus, joint surfaces are silver-plated and require
no corrosion-inhibiting compounds. Merely
wipe surfaces with a clean dry cloth. Do not
attempt to remove any discoloration. Such
discoloration is characteristic of silver.
ÇCAUTION
To ensure adequate electrical clearances,
splice plates and hardware must be
installed in the manner described and
illustrated in the text and figures that
follow. Failure to comply with these
instructions may reduce the BIL capability
of the switchgear.
Semi-conducting grommets must be
installed on the through-bushings before
installing splice plates. See Figure 12.
Failure to install grommets will result in
corona discharge between the bus splice
plates and the bushings.
Figure 13. Installation of inter-module bus splices.
Detail A, for
aluminum-to-aluminum
bus connections
Belleville washer
Copper
splice plate
Aluminum main bus or ground bus
Copper main bus or ground bus
Split lockwasher
Brass
flat washers
Copper splice plate
Belleville
washers
Aluminum
splice plate
Aluminum main bus
or ground bus
Split lockwasher Brass flat washer
Detail B, for
copper-to-copper
bus connections
Detail C, for copper-to-
aluminum bus connections

627-500
19
INSTALLATION
Step 20
Make up bus splices as follows. See Figures
13, 14 and 15.
(a) For aluminum-to-aluminum bus connec-
tions: Place the splice plate on the bottom of
the ends of the main bus sections, and on the
side of the ground bus that faces the interior
of the module. Make up the connections
using one Belleville washer under the head
of each bolt and one Belleville washer under
each nut. The bolts must be installed with
the bolt head on the top side of the main bus.
Belleville washers must be installed with
the outer ring of the cup toward the bus.
See Figure 13, Detail A. Tighten all bolts to
50 foot-pounds using a torque wrench. If a
torque wrench is not available, tighten until
the Belleville washers are flat, then back off
one-half turn. Do not use lockwashers with
Belleville washers.
(b) For copper-to-copper bus connections
(which include silver-plated copper connec-
tions): Place the splice plate on the bottom
of the ends of the main bus sections, and
on the side of the ground bus that faces the
interior of the module. Make up the connec-
tions using one brass flat washer under the
head of each bolt, and one brass flat washer
plus one split lockwasher under each nut.
The bolts must be installed with the bolt
head on the top side of the main bus. See
Figure 13, Detail B. Tighten all bolts to 35
foot-pounds using a torque wrench. If a
torque wrench is not available, tighten until
the split lockwashers are flat.
(c) For copper-to-aluminum bus connections:
Place the splice plate on the bottom of the
ends of the main bus sections, and on the
side of the ground bus that faces the interior
of the module. Make up the connections
using one Belleville washer under the head
of each bolt, and one brass flat washer under
each nut. The bolts must be installed with
the bolt head on the top side of the main bus.
See Figure 13, Detail C. Tighten all bolts to
50 foot-pounds using a torque wrench. If a
torque wrench is not available, tighten until
the Belleville washers are flat, then back off
one-half turn. Do not use lockwashers with
Belleville washers.
Figure 14. Installation of bus splice plates for through-
bushings.
Figure 15. Splice plates must be placed between the main
bus and bolts.

627-500 20
INSTALLATION
Step 21
Connect the ground bus (or ground pad
on single module assembly) to the system
grounding facility in accordance with the user’s
standard grounding practice. Use a cable not
smaller than 1/0 copper, or equivalent. If the
maximum momentary rating of the switchgear
is to be realized, the equivalent of 750 kc mil
of copper cable is required, in either a single
or multiple connection.
Step 22
Make up the medium-voltage cable
terminations, following the cable-terminator
manufacturer’s instructions and clearances
shown in Figure 16.
ÇWARNING
Maintain proper clearances when
installing cable terminators. Failure to
maintain proper clearances can result
in a flashover, injury, and equipment
damage.
To maintain the rated BIL, the following
minimum clearances are required:
Rating, kV Minimum Clearances, Inches
Nom. BIL To electrical
ground
To insulating
barriers
13.8
25
95
125
6
7.5
1
2.25
Figure 16. Dimensions and layout of cable terminations.
66³⁄₄
1³⁄₄
15⁷⁄₈
27
1³⁄₄
66³⁄₄
5¹⁄₂
24⁷⁄₈
15³⁄₈
1³⁄₄
66³⁄₄
9¹⁄₈
26¹⁄₄
Detail A, for all modules with switches only
Detail B, for modules with live-front fuse handling
Detail C, for modules with enhanced
fuse handling