SIEBREAK and SIEBREAK-VCB non-arc-resistant, air-insulated, metal-enclosed interrupter switchgear

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Rated short-time current up to 38 rms kA
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Rated continuous current up to 1,200 A
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Lightning impulse (BIL) up to 95 kV
Air-insulated, medium-voltage, non-arc-resistant, metal-enclosed interrupter switchgear, type SIEBREAK
Siemens SIEBREAKTM metal-enclosed interrupter switchgear design is a modular product available in switch and fuses configuration assembled and fully integrated both mechanically and electrically to provide medium-voltage circuit protection. All components are fully tested to perform in accordance with Siemens' standards for reliability, quality, and service.
SIEBREAK switchgear is available in both fused and unfused configurations. Supplied in the unfused configuration, short-circuit protection is not available - only load-current interruption. Supplied fused or unfused, a load-interrupter switch is different from a vacuum circuit breaker in that it will interrupt load current, but not overload or fault currents.
Fused switches are available with current-limiting or expulsion (power) fuses. Fuses extend the range of applications up to the maximum ratings of the fuse, as much as 50 kA for current-limiting fuses.
A complete product line for various distribution applications:
Standalone bay
Transformer primary
Lineups (i.e., main-tie-main, main feeders, automatic transfer).
Air-insulated, medium-voltage, non-arc-resistant, metal-enclosed interrupter switchgear, type SIEBREAK
Features
Features include:
5 kV and 15 kV voltage rated classes
600 A and 1,200 A continuous current
Non-fused or fused with current-limiting or expulsion (power) fuses
Indoor type 1 enclosure
Single, duplex, and selector switch types
Large 8" x 18" (203 mm x 457 mm) viewing window
Hinged, grounded, metal barrier in front of switch blades
11-gauge doors, covers, and barriers
Silver-plated copper bus bar
Full-length ground bus
ANSI 61 (grey) paint
Phase barriers
Provisions for key interlock
Mechanical door and switch interlock
Ventilation louvers in top and bottom, front and rear
Glass-polyester bus supports
Non-corrosive nameplate
Switch padlock provisions
Standard arrangements with automatic-transfer control systems
Space heater (half-voltage) with thermostat (optional)
NEMA hole patterns for cable termination.
Modular configurations:
Surge arresters
Instrument transformers - current transformers (CTs) or voltage transformers (VTs)
Control power transformer (CPT)
Power meter
Other auxiliary equipment.
Standard outdoor features:
Bottom cable-entry cover plate
Removable filters
6" (152 mm) formed steel base
Outdoor NEMA 3R enclosure.
Optional:
UL and C-UL listings
Indoor type 2 drip-proof enclosure
Indoor type 12 dust-resistant enclosure
Tin-plated copper bus bars
Motor-operated mechanism
High-track resistance bus support
Auxiliary switches (2 NO-2 NC)
Mimic bus
Ground studs
Screens and filters (indoor)
- Special paint color
- Channel sills.
Construction, standards, and switch types
Construction
SIEBREAK metal-enclosed interrupter switchgear enclosure is of metal-enclosed construction as described in ANSI/IEEE standards. The equipment is tested and factory assembled into convenient shipping groups. It is ruggedly constructed of 11-gauge sheet steel including the doors. The assembly employs bolted construction. SIEBREAK's modular design is available in many different enclosure types and bus configurations. The switch mechanism is arranged in the upper portion of the enclosure while the fuses are located in the lower portion. Switch and fuses are arranged for ease of operation and inspection. A large viewing window is standard for observing the position of the switch blades when the door is closed. The front door and switch operating mechanism are interlocked to prohibit access to the switch compartment when the switch is closed and prohibit operating the switch operating mechanism when the door is open.
Standards
SIEBREAK metal-enclosed switchgear meets or exceeds the requirements of the following standards:
- ANSI/IEEE C37.20.3
- ANSI/IEEE C37.20.4
- ANSI C37.57
- ANSI C37.58
- CSA 22.2 No. 31 (for Canada)
- CSA 22.2 No. 58 (for Canada)
- CSA 22.2 No 193 (for Canada).
SIEBREAK switchgear assemblies can optionally be listed with UL and, for use in Canada, have C-UL listing certifying compliance with Canadian standards and codes.
A complete line of switch types: single, duplex, and selector.
Single-source application: Single (left in image)
Single vertical section equipped with one 600 A or 1,200 A load-interrupter switch rated up to 15 kV with cable incoming-line termination and load-cable termination. Cable direction for incoming and outgoing cable entry either top or bottom with an option for close-coupled line or load connection to dry- or liquid-filled type transformer.
Dual-dource application: Duplex (center in image)
Two close-coupled vertical sections each equipped with one 600 A or 1,200 A load-interrupter switch rated up to 15 kV. Incoming and outgoing cable direction for either top or bottom cable entry with an option for close-coupled load connection to dry- or liquid-filled type transformer.
Dual-source application: Selector (right in image)
Single vertical section equipped with one 600 A load-interrupter switch rated up to 15 kV and one 600 A non-load-interrupting, two-position selector switch for selective source capability. Cable direction for incoming and outgoing cable entry either top or bottom with an option for close-coupled load connection to dry- or liquid-filled type transformer.
TechTopics is a series of papers that discuss issues of interest to users or specifiers of electrical equipment.
- No. 07 - Current transformers - Use of 600 V CTs in metal-clad switchgear
- No. 15 - Expected life of electrical equipment
- No. 16 - Bus joint fundamentals
- No. 17 - Main bus continuous current rating
- No. 18 - Bus joint and primary disconnect plating
- No. 19 - Bus joint current density
- No. 26 - Ground bus ratings
- No. 30 - Altitude correction factors
- No. 31 - Solar radiation correction factors
- No. 33 - Clearance requirements in switchgear and control equipment
- No. 44 - Anatomy of a short circuit
- No. 56 - Switchgear outdoor enclosure type - Why isn’t it NEMA 3?
- No. 57 - Arc-flash hazard labels
- No. 59 - Control power sources for switchgear
- No. 60 - Use of cable for connections in medium-voltage switchgear
- No. 66 - Clearances
- No. 75 - Ferroresonance in ungrounded systems with voltage transformers connected line-to-ground
- No. 79 - Working space required around electrical equipment
- No. 81 - Arc-flash incident energy mitigation
- No. 82 - Continuous current capability in ambient temperatures other than 40 °C
- No. 84 - Space heater - sizing and application principles
- No. 85 - Temperature limitations for user’s power cables
- No. 86 - Use of unshielded cables for connections in medium-voltage switchgear and motor controllers
- No. 88 - Application of maintenance grounds in switchgear
- No. 90 - Temperature ratings for external cables
- No. 91 - Current transformer relaying accuracies - IEEE compared to IEC
- No. 96 - Phase sequence versus phase arrangement
- No. 100 - Third-party listing - UL, C-UL and CSA
- No. 102 - Tapered bus
- No. 110 - Corrosion prevention effects on electrical equipment life
- No. 115 - Third-party listing/labeling and recognition
- No. 118 - Bolted construction vs. welded construction
- No. 119 - Momentary ratings – peak or rms?
- No. 120 - High-potential testing – current doesn’t matter!
- No. 122 - Current transformer thermal-rating factor
- No. 126 - Testing of vacuum interrupters with dc test sets
- No. 127 - High-voltage fuses - expulsion (power) and current-limiting types
- No. 131 - Heat generation estimation for SIEBREAK™ metal-enclosed interrupter switchgear
- Entire TechTopics catalog
Air-insulated, medium-voltage, non-arc-resistant, switch and circuit breaker combination metal-enclosed interrupter switchgear, type SIEBREAK-VCB
Siemens SIEBREAK-VCBTM metal-enclosed interrupter switchgear design is a modular product available in switch and fixed-mounted vacuum circuit breaker configuration assembled and fully integrated both mechanically and electrically to provide medium-voltage circuit protection. All components are fully tested to perform in accordance with Siemens' standards for reliability, quality, and service.
Siemens SIEBREAK-VCB metal-enclosed switch and circuit breaker combination is modular assembly consisting of a load-interrupter switch mechanism connected in series with a Siemens fixed-mounted vacuum circuit breaker to provide a safe, cost effective, reliable, and flexible solution for use in standalone, low-voltage substations transformer primary, and lineup configurations. Visible disconnect is provided by the load-interrupter switch and protection is provided by the fixed-mounted vacuum circuit breaker
A complete product line for various distribution applications:
- Standalone bay
- Transformer primary
- Lineups (i.e., main-tie-main, main feeders, automatic transfer).
A complete line of switch types:
- Single switch
- Duplex switch.
Vacuum interrupters
Vacuum interrupters are the centerpiece of our medium-voltage products. The hermetically sealed vacuum contact gap keeps the switching characteristics of the interrupters constant throughout their entire lifecycle. Special contact materials made by Siemens ensure that our vacuum interrupters offer absolutely top performance. With valuable features that include high short-circuit switching capacity and minimum forward resistance, they ensure reliable switching even under difficult environmental conditions – like vibration and fluctuating frequencies – regardless of whether they’re installed horizontally or vertically. Our vacuum interrupters can perform up to 30,000 operating cycles when used in circuit breakers and up to three million for contactors.
Air-insulated, medium-voltage, non-arc-resistant, switch and circuit breaker combination, metal-enclosed interrupter switchgear
Features
Features include:
- 5 kV and 15 kV voltage classes
600 A and 1,200 A continuous current
Siemens overcurrent protection relay
Indoor type 1 enclosure
Single and duplex switch types
Large 8” x 18” (203 mm x 457 mm) viewing window
Hinged, grounded metal barrier in front of switch blades
11-gauge doors, covers, and barriers
Silver-plated copper bust
Provisions for key interlocking
Mechanical door and switch interlock
Upper and lower ventilation louvers
Glass-polyester bus supports
Non-corrosive nameplate
Space heater with thermostat (optional)
NEMA CC1 hole patterns for cable termination
Current transformers (CTs) - one per phase.
Modular configurations:
- Surge arresters
- Instrument transformers - current transformers (CTs) or voltage transformers (VTs)
- Control power transformer (CPT)
- Power meter.
Standard outdoor features:
- Long-life space heaters (half-voltage)
Bottom cover plate
Externally removable filters
6” (152 mm) formed steel base.
Optional:
- UL or C-UL Listing
Indoor type 2 drip-proof enclosure
Indoor type 12 dust-resistant enclosure
Outdoor non-walk-in type 3R enclosure
High-track resistance bus supports
Auxiliary switches (2 NO-2 NC)
Mimic bus
Ground studs (ball stud) type
Screens and filters (indoor)
Tin-plated copper bus
Second set of current transformers.
Construction, standards, and switch types
Construction
SIEBREAK-VCB metal-enclosed interrupter switchgear enclosure is of metal-enclosed construction as described in ANSI/IEEE standards. The equipment is tested and factory assembled into convenient shipping groups. It is ruggedly constructed of 11-gauge sheet steel including the doors. The assembly employs bolted construction. SIEBREAK-VCB's modular design is available in many different enclosure types and bus configurations. The switch mechanism is arranged in the upper portion of the enclosure while the fuses or fixed-mounted circuit breaker are located in the lower portion. Switch and fuses or fixed-mounted circuit breaker are arranged for ease of operation and inspection. A large viewing window is standard for observing the position of the switch blades when the door is closed. The front door and switch operating mechanism are interlocked to prohibit access to the switch compartment when the switch is closed and prohibit operating the switch operating mechanism when the door is open.
Standards
SIEBREAK-VCB metal-enclosed switchgear meets or exceeds the requirements of the following standards:
- ANSI/IEEE C37.20.3
- ANSI/IEEE C37.20.4
ANSI/IEEE C37.04
ANSI/IEEE C37.09
ANSI C37.54.
- ANSI C37.57
- ANSI C37.58
- CSA 22.2 No. 31 (for Canada)
- CSA 22.2 No. 58 (for Canada)
- CSA 22.2 No 193 (for Canada).
SIEBREAK-VCB switchgear assemblies can optionally be listed with UL and, for use in Canada, have C-UL listing certifying compliance with Canadian standards and codes.
A complete line of switch types: single, duplex, and selector.
Single-source application: Single switch and circuit breaker (left in image)
Single vertical section equipped with one 600 A or 1,200 A load-interrupter switch and fixed-mounted vacuum circuit breaker rated up to 15 kV with cable incoming-line termination and load-cable termination. Cable direction for incoming and outgoing cable entry either top or bottom with an option for close-coupled line or load connection to dry or liquid-filled type transformer.
Dual-dource application: Duplex (right in image)
Two close-coupled vertical sections each equipped with one 600 A or 1,200 A load-interrupter interrupter switch and a common bus connection to a fixed-mounted vacuum circuit breaker rated up to 15 kV. Incoming and outgoing cable direction for either top or bottom cable entry with an option for close-coupled load connection to dry- or liquid-filled type transformer.
Reducing the arc-flash incident energy in low-voltage substation applications with SIEBREAK-VCB™ metal-enclosed interrupter switchgear with OMARS
Arc-flash mitigation is at the forefront today
NFPA 70E Standard for Electrical Safety in the Workplace® has increased the emphasis for greater measures for reducing arc-flash hazards in the secondary bus protection in the substation. Siemens SIEBREAK-VCB with operation and maintenance arc-flash reduction system (OMARS) offers a practical approach to providing both primary and secondary bus protection to reduce the incident energy associated with an arcing fault on the line side of the low-voltage
main circuit breaker, or on the low-voltage main bus if there is no low-voltage main circuit breaker.
The right solution to arc-flash hazard
SIEBREAK-VCB with OMARS solves the arc-flash safety hazard situation present in many existing installed substations in operation today with the traditional fused load-interrupter switch.
The fused primary load-interrupter switch in the existing substations can be replaced with SIEBREAK-VCB with OMARS to reduce the arc-flash hazard.
Configuration
Current transformers or sensors and protective relays can be installed in the low-voltage switchgear or switchboard for
input into SIEBREAK-VCB circuit protection system. In this configuration, the bus protection will be provided on the both the primary and secondary bus to reduce the arc-flash incident energy on the secondary.
Three ways for reducing the arc-fault incident energy
SIEBREAK-VCB is available in three advanced ways for reducing the incident arc-fault energy on the secondary bus of substation:
- Relay maintenance mode setting
- Fiber optics arc-flash detection system
- Short-circuit relay protection on the secondary bus.
Double-ended substation arrangement features and options
SIEBREAK-VCB applied in a double-ended substation arrangement offers several optional features including:
- Short-circuit protection on the secondary side of each transformer (secondary bus in the low-voltage equipment)
- Increased reliability and protection with redundancy between the protective relays located in each SIEBREAK unit
- Power metering with voltage transformer installed in SIEBREAK or the secondary equipment
- Transformer differential relay (87T) protection for enhanced system and transformer protection
- Arc-flash detection fiber for increased the safety against arc flash can be installed throughout the low-voltage equipment.
SIEBREAK-VCB configuration in low-voltage or medium-voltage substations
Reduction of arc-flash incident energy
For the configurations where SIEBREAK-VCB is used as the transformer primary for the low-voltage substation that is
configured with the arc-flash reduction technology, the incident energy can be reduced to as low as 2.1 cal/cm2 with an
interrupting time of 60 ms.
By contrast, for the scenario where the traditional fused load-interrupter switch is used as the transformer primary for the low-voltage substation, the incident energy can be as high 38.3 cal/cm2 (or even higher) with an interrupting time of 900 ms.
SIEBREAK-VCB is available in four advanced configurations for reducing the incident arc-fault energy on the secondary bus of substation:
Configurations #1 and #3: Low-voltage circuit breaker configurations
SIEBREAK-VCB equipped with a Siemens 7UT8 transformer differential protective relay along with an additional set of current transformers located in the auxiliary compartment of the low-voltage equipment provides a reliable system for reducing the incident energy on the secondary bus thus reducing the arc-flash hazard in this area. Optionally, the protective relay can be equipped with an arc-flash detection module for additional arc-flash protection and mitigation.
Configurations #2 and #4: Virtual main configuration
Same as configurations #1 and #3 except the low-voltage equipment is installed remote from the SIEBREAK-VCB panel. The current transformers in the low-voltage auxiliary compartment will be hardwired directly to the 7UT8 protective relay in the SIEBREAK-VCB panel. The type Siemens7SJ82 protective relay located in the low-voltage switchgear or switchboard is used primarily for the optional arc-flash detection system to transfer the trip signal to the 7UT8 protective relay. For this option, the 7SJ82 protective relay connection is hardwired or fiber-optic cable connected to the 7UT8 protective relay located in the SIEBBREAK-VCB panel. The type or connection is depended upon the customer‘s preference to run hardwires or fiber-optic cables. In most cases, the decision on whether to use hardwire or fiber optic is based on various factors. Please consult factory.
TechTopics is a series of papers that discuss issues of interest to users or specifiers of electrical equipment.
- No. 07 - Current transformers - Use of 600 V CTs in metal-clad switchgear
- No. 15 - Expected life of electrical equipment
- No. 16 - Bus joint fundamentals
- No. 17 - Main bus continuous current rating
- No. 18 - Bus joint and primary disconnect plating
- No. 19 - Bus joint current density
- No. 26 - Ground bus ratings
- No. 30 - Altitude correction factors
- No. 31 - Solar radiation correction factors
- No. 33 - Clearance requirements in switchgear and control equipment
- No. 44 - Anatomy of a short circuit
- No. 56 - Switchgear outdoor enclosure type - Why isn’t it NEMA 3?
- No. 57 - Arc-flash hazard labels
- No. 59 - Control power sources for switchgear
- No. 60 - Use of cable for connections in medium-voltage switchgear
- No. 66 - Clearances
- No. 75 - Ferroresonance in ungrounded systems with voltage transformers connected line-to-ground
- No. 79 - Working space required around electrical equipment
- No. 81 - Arc-flash incident energy mitigation
- No. 82 - Continuous current capability in ambient temperatures other than 40 °C
- No. 84 - Space heater - sizing and application principles
- No. 85 - Temperature limitations for user’s power cables
- No. 86 - Use of unshielded cables for connections in medium-voltage switchgear and motor controllers
- No. 88 - Application of maintenance grounds in switchgear
- No. 90 - Temperature ratings for external cables
- No. 91 - Current transformer relaying accuracies - IEEE compared to IEC
- No. 96 - Phase sequence versus phase arrangement
- No. 100 - Third-party listing - UL, C-UL and CSA
- No. 102 - Tapered bus
- No. 110 - Corrosion prevention effects on electrical equipment life
- No. 115 - Third-party listing/labeling and recognition
- No. 118 - Bolted construction vs. welded construction
- No. 119 - Momentary ratings – peak or rms?
- No. 120 - High-potential testing – current doesn’t matter!
- No. 122 - Current transformer thermal-rating factor
- No. 126 - Testing of vacuum interrupters with dc test sets
- No. 127 - High-voltage fuses - expulsion (power) and current-limiting types
- No. 128 - Arc-fault mitigation in unit substations with type SIEBREAK-VCB primary switchgear
- No. 131 - Heat generation estimation for SIEBREAK™ metal-enclosed interrupter switchgear
- Entire TechTopics catalog

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