7126 -Technical Specifications for ELECTRIC UTILITY PADMOUNTED SWITCHGEARRFP 7126– Technical Specifications Page 1 of 15
Technical Specifications
RFP # 7126
Supply of S&C PME-Type Pad-Mounted Switchgear
A. PURPOSE
The City of Denton is providing information that will allow prospective suppliers to prepare
quotations to furnish new S&C, PME type, pad-mounted switchgear equipped as set forth in
this specification. Only new switchgear with parts unused will be accepted on this bid. Salvaged
material or remanufactured parts from any other source will not be acceptable. Manufacturer shall
provide a statement with their bid that only new parts and materials will be used on all PME
switchgear supplied to the City of Denton.
There are three (3) different types of switchgear proposed in this RFP:
1) 600 Amp
2) 600 Amp with provisions for automation
3) 200 Amp (-M4 Suffix, Source side)
The switchgear shall be designed to operate on Denton Municipal Eclectic’s (DME) 13.2 kV
Grounded-Wye/7.62 kV electric distribution system. The bidder shall supply all types of PME
type, pad-mounted switchgear that the City of Denton will require on an annual basis for a five-
year term. The switchgear proposed by prospective suppliers shall conform to this specification.
The PME type, pad-mounted switchgear shall consist of a single, self-supporting, pad-mounted
enclosure, containing interrupter switches, and power fuse holders with the necessary accessory
components. All components and accessories shall be completely factory-assembled and
operationally checked. The interrupter switches and fuse holders shall be enclosed within an inner-
grounded steel compartment for electrical isolation and protection from contamination.
The 600A manual & automated units shall have 600A continuous “T-Body” style terminators at
the switch terminals on the source-side. The fuse and bus terminals shall be equipped with
bushing-wells rated 200A continuous to provide for elbow connections.
The 200A manual units shall have 200A continuous bushing-wells in lieu of 600A bushings at
the switch terminals on the source-side. The fuse and bus terminals shall be equipped with
bushing-wells rated 200A continuous to provide for elbow connections.
Bushings and bushing-wells shall be mounted on the walls of the inner compartment and extend
into the termination compartments. A termination compartment shall be provided for each three-
phase switch, each three-phase set of fuses, and each three-phase set of bus terminals.
RFP 7126– Technical Specifications Page 2 of 15
Minimum Ratings for the Pad-Mounted Switchgear
Switchgear Source-Side Ampacity 600A 200A
Frequency 60 Hz 60 Hz
Nominal Voltage 14.4 kV 14.4 kV
Maximum Voltage 17.0 kV 17.0 kV
BIL 95 kV 95 kV
Short-Circuit
Peak Withstand Current, Amperes, Peak 36,400 36,400
One-Second Short-Time Withstand
Current, Amperes, RMS, Symmetrical 14,000 14,000
MVA, Three-Phase Symmetrical, at
Rated Nominal Voltage 350 350
Main Bus
Continuous Current, Amperes 600 600
Peak Withstand Current, Amperes, Peak 65,000 65,000
One-Second Short-Time Withstand
Current, Amperes, RMS, Symmetrical 25,000 25,000
Three-Pole
Interrupter Switches
Continuous Current, Amperes 600 200
Load Dropping Current, Amperes 600 200
Peak Withstand Current, Amperes, Peak 65,000 65,000
One-Second Short-Time Withstand
Current, Amperes, RMS, Symmetrical 14,000 14,000
Three-Time Duty-Cycle Fault-Closing
Current, Amperes, Peak 36,400 36,400
Fuses Maximum Current, Amperes 200E or 200K 200E or 200K
B. SUBMISSIONS
Additional information clarifying the supplier’s product shall be attached to their submission.
Pricing must include all costs to deliver goods as detailed in this specification. Any special fees
or commissions, and all freight for delivery to DME’s Pole Yard at 1701C Spencer Road, Denton,
TX 76205 and unloading costs must be included in the quoted price. Item pricing shall be mutually
exclusive; thus, the City of Denton reserves the right to choose the best valued item from different
vendors.
C. QUALITY CONTROL
The manufacturer shall be responsible for the quality control of the manufacturing processes to
assure that all requirements of these specifications are met. However, the City reserves the right
to observe, inspect and require additional quality control investigations, either by its personnel or
an independently employed quality control investigator, at any or all stages of fabrication at the
manufacturer’s facilities. Failure to adequately maintain fabrication and quality of fabrication until
completion shall be grounds for cancellation of the order or any part thereof.
RFP 7126– Technical Specifications Page 3 of 15
Field failure or field repairs required due to quality control failures or manufacturing procedures
shall be the responsibility of the manufacturer.
D. WRITTEN WARRANTY and GUARANTEES
Written guarantees shall include any limitations as to the nature of failure or time limitations. The
guarantee shall begin upon receipt of the accepted units, not on the date of manufacture.
Guarantees shall indicate whether or not it is made on a full replacement basis or a prorated basis
and if prorated then what are the terms. Manufacturer/supplier guarantees that the goods furnished
under this specification are of high quality and agrees to replace any goods found to be defective
during inspection, installation, or service for a minimum period of 12 months after unit is delivered
to Denton. Any goods found to be defective or that do not conform to this specification upon
delivery or inspection shall be rejected and returned to the manufacturer or supplier at no cost to
DME. All replacements by the manufacturer/supplier shall be free of charge F.O.B. at the same
delivery point called for in the original order. Replacements must be handled in a professional and
timely manner and in no case shall a replacement unit take longer than 60 days to arrive in Denton
after first being submitted for replacement.
The respondent must be an approved distributor by the manufacturer of these products and
authorized to sell these products to the City of Denton. The respondent also guarantees that the
City will be represented by the Manufacturer, should an issue arise, and that all manufacturer’s
warranties will be in effect for the life of the contract.
Where the manufacturer provides warranties or guarantees as a customary trade practice; the
bidder shall furnish the City of Denton with copies of such warranties or guarantees with their
submission.
E. SHIPMENT AND DELIVERY
A delivery schedule after placing an order for the PME switchgear is required with the proposal.
The delivery lead-time for new S&C PME type, pad-mounted switchgear shall be a consideration
during the evaluation process. These products will be received and distributed by the City of
Denton’s Distribution Center Staff at the DME Pole Yard. DME’s Pole Yard is located at 1701C
Spencer Road, Denton, TX 76205. This location does not have a dock for offloading but does
have forklift(s) available to offload goods. Please provide a minimum of 24-hours’ notice to
Distribution Center Staff by calling 940-349-8000. The DME Pole Yard is an unmanned delivery
location. Driver shall contact Distribution Center prior/upon arrival. Products must be shipped,
F.O.B. Destination, via open trailer as noted on the Purchase Order. Typical shipments are made
to 1701C Spencer Road, Denton, TX 76205. Orders will be placed as needed over the contract
term. Deliveries can be made 9:00 AM – 3:00 PM, Monday through Friday, excluding holidays.
F. LEAD TIME / SPECIAL DELIVERY INSTRUCTIONS
The supplier shall furnish lead time with proposal. Lead time/delivery is part of the evaluation
criteria, and respondents must provide accurate delivery schedules. The City of Denton
understands that manufacturing and market conditions change. In order for the City to be able to
RFP 7126– Technical Specifications Page 4 of 15
order and replenish at the right time, through the life of the contract, original delivery schedules
shall not be increased by more than 20%.
G. GENERAL REQUIREMENTS
The supplier shall furnish all documentation, drawings, and instructions that are necessary to
completely and safely transport, install, and maintain each PME type, pad-mounted switchgear.
H. TECHNICAL SPECIFICATIONS FOR S&C PME 9, 10, 11 AND 12 PAD-MOUNTED
SWITCHGEAR
The new S&C PME type, pad-mounted switchgear shall meet or exceed the latest applicable ANSI
and IEEE standards. The PME type, pad-mounted switchgear shall conform to the latest revisions
of: American National Standards Institute (ANSI): ANSI C57.12.28, that covers enclosure
integrity for pad-mounted equipment and ANSI standards that apply to the basic switch and fuse
components. National Electrical Code (NEC): Note Article 710-21(e) which specifies that the
interrupter switches in combination with power fuses shall safely withstand the effects of closing,
carrying, and interrupting all possible currents up to the assigned maximum short circuit rating.
Institute of Electrical Contractors (IEC): Note IEC Publication 507, First Edition, 1975 for
adequate in-air leakage distance established by testing. All portions of ANSI, IEEE, NEMA,
ASTM and UL standards applicable to the basic switch and fuse components.
Controls System Requirements: (Supervisory Switchgear Only)
S&C IntelliTEAM Dual Automatic Reconfiguration Switch Control for use with S&C
Remote Supervisory PME pad-mounted gear. The S&C 6802 control provides
IntelliTEAM SG logic for two switched ways, with full SCADA control and analog
monitoring for multiple team members or controls. Multiple 6802 controls are provided in
PME pad-mounted gear when 3 or 4 switch ways need to be controlled.
S&C 6802 Automatic Switch Controls combine automatic control schemes with Remote
Terminal Unit (RTU) functionality, data logging, and advanced communication
capabilities in a single package. 6802 Controls manage distribution switches and can
automatically sectionalize a feeder based on such factors as overcurrent, loss of voltage,
and phase unbalance. The system uses distributed intelligence; no central processing or
SCADA is required (though fully supported).
Required 6802 Control Options:
H14 – IntelliTEAM SG Bronze Access Level Software license.
JB0 – No enclosure, mounted in S&C low voltage enclosure.
K2 – 6 voltage, 6 current sensor configuration.
P0 – DNP 3.0 protocol.
R164-R98 – RuggedCom RS900 Single-mode fiber optic modem, including ST
connectors, provided and installed by S&C.
W2 – to be powered by internal voltage.
RFP 7126– Technical Specifications Page 5 of 15
A2 – Wi-Fi Module with Antenna
Software License
008-007006-01 IntelliTEAM Designer license slot for one (1) 6802 Series Automatic
Switch control. For pad-mounted switchgear with more than two (2) automated switches,
then an additional S&C 6802 control and software license will be required.
CONSTRUCTION OF THE PME TYPE, PAD-MOUNTED SWITCHGEAR:
Insulators:
The interrupter-switch and fuse-mounting insulators shall be of a cycloaliphatic epoxy
resin system with characteristics and restrictions as follows:
a. Operating experience of at least twenty-five (25) years under similar conditions.
b. Adequate leakage distance established by test per IEC Publication 507, “Artificial
Pollution Test on High Voltage Insulators to be Used on AC Systems.”
c. Adequate strength for short-circuit stress established by test.
d. Conformance with all applicable ANSI standards.
e. Homogeneity of the cycloaliphatic epoxy resin throughout each insulator to provide
maximum resistance to power arcs. Ablation due to high temperatures from power
arcs shall continuously expose more material of the same composition and
properties so that no change in mechanical or electrical characteristics takes place
because of arc-induced ablation. Furthermore, any surface damage to insulators
during installation or maintenance of the pad-mounted gear shall expose material
of the same composition and properties so that insulators with minor surface
damage need not be replaced.
High-Voltage Bus:
a. Bus and interconnections shall consist of aluminum bar of 56% IACS conductivity.
b. Bus and interconnections shall withstand the stresses associated with short-circuit
currents up through the maximum rating of the pad-mounted gear.
c. Bolted aluminum-to-aluminum connections shall be made with a suitable number
of galvanized steel bolts, with two (2) Belleville spring washers per bolt, one under
the bolt head and one under the nut. Bolts shall be tightened to 50 foot-pounds
torque.
d. Before installation of the bus, all electrical contact surfaces shall first be prepared
by machine-abrading to remove any aluminum-oxide film. Immediately after this
operation, the electrical contact surfaces shall be coated with a uniform coating of
an oxide inhibitor and sealant.
e. Tie bus, where furnished, shall consist of continuous, one-piece sections of
aluminum bar with no intermediate splices. Flexible braid or cable shall not be used.
RFP 7126– Technical Specifications Page 6 of 15
Grounding Provisions:
a. A ground-connection pad shall be provided in each termination compartment of the
pad-mounted gear.
b. The ground-connection pad shall be constructed of steel no less than 3/8-in. thick.
It shall be nickel plated, welded to the enclosure, and shall have a short-circuit
rating equal to that of the pad-mounted gear.
c. Ground-connection pads shall be coated with a uniform coating of an oxide
inhibitor and sealant prior to shipment.
d. A copper rod, connected to the ground-connection pad, shall be provided in each
termination compartment for switches and bus. The rod shall have a diameter no
less than 3/8-in. and extend across the full width of the compartment to allow
convenient grounding of cable concentric neutrals and accessories and shall have a
short-circuit rating equal to that of the pad-mounted gear.
e. A continuous copper ground bus shall be provided across the full width of each
termination compartment for fuses. For each fuse mounting, there shall be a ground
ring made of 3/8 in.-diameter copper rod bolted to the ground bus and placed to
allow convenient grounding of cable concentric neutrals and accessories. Ground
rings and bus shall have a short-circuit rating equal to that of the pad-mounted gear.
Bushings & Bushing-Wells:
The source side of the 600A pad-mounted switchgear shall come with 600A, 15 kV dead
break bushings. The 200A switchgear shall come with 200A bushing-wells that
accommodate Elastimold 1601A4 elbows on the source side. Supplier shall furnish
Elastimold inserts (Elastimold part #: 1601A4), with dust covers and drain wire for the
200A bushing-wells. The load side of the pad-mounted switches shall come with 200A
continuous Elastimold inserts, dust covers and drain wire.
a. Bushings and bushing-wells shall conform to ANSI/IEEE Standard 386.
b. Bushings and bushing-wells shall be of a cycloaliphatic epoxy resin system with
characteristics and restrictions as specified below:
1. Adequate leakage distance for in-air application established by test per IEC
Publication 507, “Artificial Pollution Test on High Voltage Insulators to be
Used on AC Systems.”
2. Adequate strength for short-circuit stress established by test.
3. Conformance with applicable ANSI standards.
4. Homogeneity of the cycloaliphatic epoxy resin throughout each bushing or
bushing-well to provide maximum resistance to power arcs. Ablation due
to high temperatures from power arcs shall continuously expose more
material of the same composition and properties so that no change in
mechanical or electrical characteristics takes place because of arc-induced
ablation.
RFP 7126– Technical Specifications Page 7 of 15
c. Bushings and bushing-wells shall be mounted in such a way that the semi-
conductive coating is solidly grounded to the enclosure.
d. Bushings rated 600A continuous shall have a removable threaded stud so that the
bushings are compatible with all 600A elbow systems—those requiring a threaded
stud as well as those that do not.
Termination Compartments:
a. Termination compartments for switches shall have bushings, and termination
compartments for fuses shall have bushing-wells to permit connection of elbows.
The bushings and bushing-wells shall be mounted on the interior walls at a
minimum height of 33 inches (33”) above the enclosure base, or 39 inches (39”)
above the enclosure base for switchgear with the six-inch (6”) base attached.
b. Termination compartments shall provide cable guides for training cables.
Termination compartments for bus shall have bushing-wells to permit connection
of elbows. The bushing-wells shall be mounted on the interior walls at a minimum
height of 25 inches (25”) above the enclosure base.
c. Termination compartments for bushings rated 600A continuous shall be of an
adequate depth to accommodate two (2) 600A elbows mounted piggyback,
encapsulated surge arresters or grounding elbows mounted on 600A elbows having
200A interfaces, or other similar accessory combinations without the need for an
enclosure extension.
d. Termination compartments for bushing-wells rated 200A continuous shall be of an
adequate depth to accommodate 200A elbows mounted on portable feed-thrus or
standoff insulators, or other similar accessory combinations without the need for an
enclosure extension.
e. Termination compartments shall be provided with one (1) parking stand for each
bushing or bushing-well. The parking stand shall be located immediately adjacent
to the associated bushing or bushing-well and shall accommodate standard feed-
thrus and standoff insulators, and other similar accessories.
f. Each termination compartment for a switch shall be equipped with a viewing
window to allow visual inspection of interrupter switch blades to allow positive
verification of switch position.
g. Each termination compartment for a set of fuses shall be equipped with a set of
viewing windows to allow visual inspection of blown-fuse indicators.
Enclosure:
a. The pad-mounted gear enclosure shall be of unitized monocoque (not structural-
frame-and-bolted-sheet) construction to maximize strength, minimize weight, and
inhibit corrosion.
b. The basic material shall be 11-gauge hot-rolled, pickled and oiled steel sheet.
RFP 7126– Technical Specifications Page 8 of 15
c. All structural joints and butt joints shall be welded, and the external seams shall be
ground flush and smooth. The gas-metal-arc welding process shall be employed to
eliminate alkaline residues and to minimize distortion and spatter.
d. To guard against unauthorized or inadvertent entry, enclosure construction shall not
utilize any externally accessible hardware.
e. The base shall consist of continuous 90-degree flanges, turned inward and welded
at the corners, for bolting to the concrete pad.
f. The door openings shall have 90-degree flanges, facing outward, that shall provide
strength and rigidity as well as deep overlapping between doors and door openings
to guard against water entry.
g. Gasketing between the roof and the enclosure shall guard against entry of water and
airborne contaminants and shall discourage tampering or insertion of foreign
objects.
h. An internal steel-enclosed compartment shall encase the interrupter switches and
fuses for electrical isolation and protection from contamination. The compartment
shall have a galvanized steel sheet floor to exclude foliage and animals. The floor
shall have screened drain vents to allow drainage if the enclosure is flooded. The
top of this compartment shall be gasketed to provide sealing with the enclosure
roof.
i. Insulating barriers of NEMA GPO3-grade fiberglass-reinforced polyester shall be
provided for each interrupter switch where required to achieve BIL ratings.
Additional insulating barriers of the same material shall isolate the tie bus (where
furnished).
j. Full-length steel barriers shall separate adjoining termination compartments.
k. Lifting tabs shall be removable. Sockets for the lifting-tab bolts shall be blind-
tapped. A resilient material shall be placed between the lifting tabs and the
enclosure to help revent corrosion by protecting the finish against scratching by the
tabs. To further preclude corrosion, this material shall be closed-cell to prevent
moisture from being absorbed and held between the tabs and the enclosure in the
event that lifting tabs are not removed.
l. The enclosure shall be provided with an instruction manual holder.
Doors:
a. Doors shall be constructed of 11-gauge hot-rolled, pickled and oiled steel sheet.
b. Door-edge flanges shall overlap with door-opening flanges to discourage tampering
or insertion of foreign objects.
c. Doors shall have a minimum of two (2) extruded-aluminum hinges with stainless-
steel hinge pins and interlocking extruded-aluminum hinge supports for the full
length of the door to provide strength, security, and corrosion resistance. Mounting
hardware shall be stainless steel or zinc-nickel-plated steel and shall not be
externally accessible to guard against tampering.
RFP 7126– Technical Specifications Page 9 of 15
d. Doors shall be hinged at the sides to swing open with minimum effort. Doors hinged
at the top requiring significant effort to lift open shall not be allowed.
e. In consideration of controlled access and tamper resistance, each door (or set of
double doors) shall be equipped with an automatic three-point latching mechanism.
1. The latching mechanism shall be spring-loaded and shall latch
automatically when the door is closed. All latch points shall latch at the
same time to preclude partial latching.
2. A pentahead socket-wrench or tool shall be required to actuate the
mechanism to unlatch the door and, in the same motion, recharge the spring
for the next closing operation.
3. The latching mechanism shall have provisions for padlocking that
incorporate a means to protect the padlock shackle from tampering and that
shall be coordinated with the latches such that:
i. It shall not be possible to unlatch the mechanism until the padlock
is removed, and
ii. It shall not be possible to insert the padlock until the mechanism is
completely latched closed.
f. Doors providing access to solid-material power fuses shall have provisions to store
spare fuse units or refill units.
g. Each door shall be provided with a zinc-nickel-plated steel door holder located
above the door opening. The holder shall be hidden from view when the door is
closed, and it shall not be possible for the holder to swing inside the enclosure.
Roof:
a. The roof shall be constructed of 11-gauge hot-rolled, pickled and oiled steel sheet.
b. A heavy coat of insulating “no-drip” compound shall be applied to the inside
surface of the center roof section to minimize condensation of the moisture thereon.
c. Roof sections over termination compartments shall be liftable and hinged to allow
room for cable pulling during installation. Each roof section shall require minimal
effort to open and close and shall have a retainer to hold it in the open position.
d. A mechanical interlock shall be provided to ensure that the roof sections over the
termination compartments are closed and secured before allowing full engagement
of the door latching mechanism described in Section e. of “Doors:” above.
e. Roof sections over high-voltage compartments shall be bolted to the enclosure with
no exposed fasteners.
Hardware:
To guard against corrosion, all hardware (including door fittings, fasteners, etc.), all
operating mechanism parts, and other parts subject to abrasive action from mechanical
RFP 7126– Technical Specifications Page 10 of 15
motion shall be of either nonferrous materials, galvanized or zinc-nickel-plated ferrous
materials. Cadmium-plated ferrous parts shall not be used.
Finish:
a. Full coverage at joints and blind areas shall be achieved by processing enclosures
independently of components such as doors and roofs before assembly into the
unitized structures.
b. All exterior seams shall be filled and sanded smooth for neat appearance.
c. To remove oils and dirt, to form a chemically and anodically neutral conversion
coating to improve the finish-to-metal bond, and to retard underfilm propagation of
corrosion, all surfaces shall undergo a thorough pretreatment process comprised of
a fully automated system of cleaning, rinsing, phosphatizing, sealing, drying, and
cooling before any protective coatings are applied. By utilizing an automated
pretreatment process, the enclosure shall receive a highly consistent thorough
treatment, eliminating fluctuations in reaction time, reaction temperature, and
chemical concentrations.
d. After pretreatment, protective coatings shall be applied that shall help resist
corrosion and protect the steel enclosure. To establish the capability to resist
corrosion and protect the enclosure, representative test specimens coated by the
enclosure manufacturer’s finishing system shall satisfactorily pass the following
tests:
1. 4000 hours of exposure to salt-spray testing per ASTM B 117 with:
i. Underfilm corrosion not to extend more than 1/32 in. from the
scribe, as evaluated per ASTM D 1645, Procedure A, Method 2
(scraping); and
ii. Loss of adhesion from bare metal not to extend more than 1/8 in.
from the scribe.
2. 1000 hours of humidity testing per ASTM D 4585 using the Cleveland
Condensing Type Humidity Cabinet, with no blistering as evaluated per
ASTM D 714.
3. 500 hours of accelerated weathering testing per ASTM G 53 using lamp
UVB-313, with no chalking as evaluated per ASTM D 659, and no more
than 10% reduction of gloss as evaluated per ASTM D 523.
4. Crosshatch-adhesion testing per ASTM D 3359 Method B, with no loss of
finish.
5. 160-inch-pound impact, followed by adhesion testing per ASTM D 2794,
with no chipping or cracking.
6. 3000 cycles of abrasion testing per ASTM 4060, with no penetration to the
substrate.
RFP 7126– Technical Specifications Page 11 of 15
e. After the finishing system has been properly applied and cured, welds along the
enclosure bottom flange shall be coated with a wax-based anticorrosion moisture
barrier to give these areas added corrosion resistance.
f. A resilient closed-cell material, such as PVC gasket, shall be applied to the entire
underside of the enclosure bottom flange to protect the finish on this surface from
scratching during handling and installation. This material shall isolate the bottom
flange from the alkalinity of a concrete foundation to help protect against corrosive
attack.
g. After the enclosure is completely assembled and the components (switches, fuses,
bus, etc.) are installed, the finish shall be inspected for scuffs and scratches.
Blemishes shall be touched up by hand to restore the protective integrity of the
finish.
h. The finish shall be olive green, Munsell 7GY3.29/1.5.
Interrupter Switches:
a. Interrupter switches shall be enclosed in an inner steel compartment and shall be
provided with bushings rated 600A continuous to permit connection of elbows
external to the switch compartment.
b. Interrupter switches shall have a three-time duty-cycle fault-closing rating equal to
or exceeding the short-circuit rating of the pad-mounted gear. These ratings define
the ability to close the interrupter switch three (3) times against a three-phase fault
with asymmetrical current in at least one phase equal to the rated value, with the
switch remaining operable and able to carry and interrupt rated current. Tests
substantiating these ratings shall be performed at maximum voltage with current
applied for at least 10 cycles. Certified test abstracts establishing such ratings shall
be furnished upon request.
c. Interrupter switches shall be operated by means of an externally accessible 3/4-in.
hex switch-operating hub. The switch-operating hub shall be located within a
recessed stainless-steel pocket mounted on the side of the pad-mounted gear
enclosure and shall accommodate a 3/4-in.deep-socket wrench or a 3/4-in. shallow
socket wrench with extension. The switch-operating-hub pocket shall include a
pad-lockable stainless-steel access cover that shall incorporate a hood to protect the
padlock shackle from tampering. Stops shall be provided on the switch operating
hub to prevent overtravel and thereby guard against damage to the interrupter
switch quick-make quick-break mechanism. Labels to indicate switch position shall
be provided in the switch-operating-hub pocket.
d. Each interrupter switch shall be provided with a folding switch-operating handle.
The switch-operating handle shall be secured to the inside of the switch-operating
hub pocket by a brass chain. The folded handle shall be stored behind the closed
switch-operating-hub access cover.
e. Interrupter switches shall utilize a quick-make quick-break mechanism installed by
the switch manufacturer. The quick-make quick-break mechanism shall be
RFP 7126– Technical Specifications Page 12 of 15
integrally mounted on the switch frame and shall swiftly and positively open and
close the interrupter switch independent of the switch-operating-hub speed.
f. Each interrupter switch shall be completely assembled and adjusted by the switch
manufacturer on a single rigid mounting frame. The frame shall be of welded steel
construction such that the frame intercepts the leakage path which parallels the open
gap of the interrupter switch to positively isolate the load circuit when the
interrupter switch is in the open position.
g. Interrupter switch contacts shall be backed up by stainless-steel springs to provide
constant high contact pressure.
h. Interrupter switches shall be provided with a single blade per phase for circuit
closing, including fault closing, continuous current carrying, and circuit
interrupting. Spring-loaded auxiliary blades shall not be permitted. Interrupter
switch blade supports shall be permanently molded in place in a unified insulated
shaft constructed of the same cycloaliphatic epoxy resin as the insulators.
i. Circuit interruption shall be accomplished by use of an interrupter which is
positively and inherently sequenced with the blade position. It shall not be possible
for the blade and interrupter to get out of sequence. Circuit interruption shall take
place completely within the interrupter, with no external arc or flame. Any exhaust
shall be vented in a controlled manner through a deionizing vent.
j. Key interlocks shall be provided to prevent paralleling the two source interrupter
switches.
k. Key interlocks shall be provided to guard against opening the door(s) of fuse-
termination compartment(s) unless all switches are locked open.
l. Mounting provisions shall be provided to accommodate one (1) three-phase fault
indicator with three (3) single-phase sensors in each switch-termination
compartment.
Solid-Material Power Fuses:
Denton Municipal Electric will use solid-material power fuses in the distribution pad-
mounted, PME 9, 11, and 12 switchgear. Because the PME pad-mounted switchgear
applications will vary from customer to customer, Denton Municipal Electric will purchase
and maintain stock for the PME pad-mounted switchgear fuses.
Fuses shall NOT be included in the bid quote.
Denton Municipal Electric stocks the following S&C SMU-20 fuse units for use in the
PME 9, 11, and 12, pad-mounted switchgear: 10E, 15E, 20E, 25E, 30E, 40E, 50E, 65E,
80E, 100E, & 125E.
Each fuse in the PME switchgear shall be an integral part of the fuse handling mechanism so
that it does not allow access to the fuse until the fuse elbow is completely disconnected.
RFP 7126– Technical Specifications Page 13 of 15
S&C 3093 FUSE-END FITTINGS SHALL BE PROVIDED with the PME for each position.
a. Solid-material power fuses shall utilize refill-unit-and-holder or fuse-unit and-end-
fitting construction. The refill unit or fuse unit shall be readily replaceable and low
in cost.
b. Fusible elements shall be non-aging and non-damageable, so it is unnecessary to
replace unblown companion fuses following a fuse operation.
c. Fusible elements for refill units or fuse units, rated 10 amperes or larger, shall be
helically coiled to avoid mechanical damage due to stresses from current surges.
d. Fusible elements that carry continuous current shall be supported in air to help
prevent damage from current surges.
e. Refill units and fuse units shall have a single fusible element to eliminate the
possibility of unequal current sharing in parallel current paths.
f. Solid-material power fuses shall have melting time-current characteristics that are
permanently accurate to within a maximum total tolerance of 10% in terms of
current. Time-current characteristics shall be available which permit coordination
with source-side and load-side protective relays, automatic circuit reclosers, and
other fuses.
g. Solid-material power fuses shall be capable of detecting and interrupting all faults,
whether large, medium, or small (down to minimum melting current); under all
realistic conditions of circuitry; and with line-to-line or line-to-ground voltage
across the fuse. They shall be capable of handling the full range of transient
recovery voltage severity associated with these faults.
h. All arcing accompanying solid-material power fuse operation shall be contained
within the fuse, and all arc products and gases evolved shall be effectively
contained within the exhaust control device during fuse operation.
i. Solid-material power fuses shall be equipped with a blown-fuse indicator that shall
provide visible evidence of fuse operation while installed in the fuse mounting.
j. A fuse-storage feature shall be provided in (one, two) source interrupter-switch
compartment(s). Each fuse-storage feature shall provide space for storing three
spare fuse holders or fuse units with end fittings for solid-material power fuses.
Labeling:
Hazard-Alerting Signs:
a. All external doors shall be provided with “Warning—Keep Out—Hazardous
Voltage Inside—Can Shock, Burn, or Cause Death” signs.
b. The inside of each door shall be provided with a “Danger—Hazardous Voltage—
Failure to Follow These Instructions Will Likely Cause Shock, Burns, or Death”
sign. The text shall further indicate that operating personnel must know and obey
the employer’s work rules, know the hazards involved, and use proper protective
equipment and tools to work on this equipment.
RFP 7126– Technical Specifications Page 14 of 15
c. Termination compartments shall be provided with “Danger—Keep Away—
Hazardous Voltage—Will Shock, Burn, or Cause Death” signs.
Nameplates, Ratings Labels, and Connection Diagrams:
a. The outside of each door (or set of double doors) shall be provided with a
nameplate indicating the manufacturer’s name, catalog number, model number,
date of manufacture, and serial number.
b. The inside of each door (or set of double doors) shall be provided with a rating’s
label indicating the following:
1. Overall pad-mounted gear ratings: nominal voltage, kV; maximum
voltage, kV; BIL voltage, kV; power frequency, Hz; short-circuit peak
withstand current, amperes, peak; short-circuit one-second short-time
withstand current, amperes, RMS, symmetrical; and short-circuit MVA,
three-phase symmetrical, at rated nominal voltage.
2. Main bus ratings: continuous current, amperes; peak withstand current,
amperes, peak; and one-second short-time withstand current, amperes,
RMS symmetrical.
3. Switch ratings: continuous current, amperes; load splitting current,
amperes; load dropping current, amperes; peak withstand current,
amperes, peak; one-second short-time withstand current, amperes,
RMS, symmetrical; and three-time duty-cycle fault-closing current,
amperes, RMS symmetrical and amperes, peak.
4. Fuse type and ratings: maximum current, amperes and interrupting
current, amperes, RMS, symmetrical.
c. A three-line connection diagram showing interrupter switches, fuses, and bus
along with the manufacturer’s model number shall be provided on the inside of
each door (or set of double doors), and on the inside of each switch-operating-
hub access cover.
I. ACCEPTABLE MANUFACTURERS and CATALOG NUMBER:
The City will only accept submissions from specific manufacturers listed in the approved
manufacturers list below. Proposals offering alternate manufacturers/products will not be
considered at this time.
DME Engineering Description S&C Catalog Number
SWITCHGEAR, PME9, 200A 65152R1-E1F2KM4-S393
SWITCHGEAR, PME10, 200A 65242R1-E1F2KM4-S393
SWITCHGEAR, PME11, 200A 65162R1-E2F2KM4-S393
SWITCHGEAR, PME12, 200A 65172R1-E2F2KM4-S393
SWITCHGEAR, PME9, 600A 65152R1-E1F2K-S393
RFP 7126– Technical Specifications Page 15 of 15
DME Engineering Description S&C Catalog Number
SWITCHGEAR, PME10, 600A 65242R1-F2K
SWITCHGEAR, PME11, 600A 65162R1-E1F2K-S393
SWITCHGEAR, PME12, 600A 65172R1-E2F2K-S393
SWITCHGEAR, PME9, 600A, SUPERVISORY 266152R3-E1F2KY2-S393
SWITCHGEAR, PME9, 600A, SUPERVISORY, NR 66252R1-F2Y2Y8-E107
SWITCHGEAR, PME10, 600A, 2 SUPERVISORY 266242R3-F2KY2-S393
SWITCHGEAR, PME10, 600A, 3 SUPERVISORY 366242R3-F2KY2-S393
SWITCHGEAR, PME10, 600A, 4 SUPERVISORY 466242R3-F2KY2-S393
SWITCHGEAR, PME11, 600A, 2 SUPERVISORY 266162R3-E1F2KY2-S393
SWITCHGEAR, PME11, 600A, 3 SUPERVISORY 366162R3-E1F2KY2-S393
For each of the PME switchgear provided, the following shall be included: 6–S&C 3093 fuse-
end fittings for PME 9’s, 3-S&C 3093 fuse-end fittings for the PME 11, and 9–S&C 3093
fuse-end fittings for PME 12’s. Only S&C products that meet all of the above specification
criteria and have exactly the same type of switch and fuse operating mechanism will be considered.
The City has implemented a pre-approval process for substitution commodities and services.
Vendors are encouraged to submit forms and samples for consideration on the next solicitation for
similar items. Supporting documentation or samples must be submitted for review by Purchasing,
Engineering, field crews, and the manager of DME. Testing may be required and may take
substantial time to review. The commodity approval form can be obtained via email
(warehouse@cityofdenton.com).