The document summarizes the MNS-SG low voltage switchgear. It discusses the workshop agenda, industry standards the switchgear complies with, its arc-resistant and mechanical features. Key specifications like ratings, dimensions and components are outlined. The switchgear is designed for oil/gas, mining, utilities and other industrial markets.

1. MNS Systems Workshop 2013
MNS-SG Technical Description
29th – 30th October 2013, Rodrigo Morales

2. © BU 3101 Low Voltage Systems
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MNS-SG
 Arc Flash
 Industry Standards/Markets
 Arc Resistant Features
 Equipment Ratings
 Mechanical Overview
 Electrical Overview
 Arc Flash Mitigation
 Arc Mitigation

3. Industry Standards
MNS-SG Switchgear is designed, tested, and constructed to meet/exceed these standards:
 UL 1558 — Metal-Enclosed Low Voltage Power Circuit Breaker Switchgear
 ANSI C37.20.1 — IEEE Standard for Metal-Enclosed Low Voltage Power Circuit Breaker
Switchgear
 ANSI C37.20.7 ---- IEEE Guide for Testing Metal-Enclosed Switchgear Rated Up to 38kv
for Internal Arcing Faults
 ANSI C37.50 — Test Procedure for Low Voltage AC Power Circuit Breakers Used in
Enclosures
 ANSI C37.51 — Conformance Testing of Metal-Enclosed Low Voltage AC Power Circuit
Breaker Switchgear Assemblies
 Seismic Qualification to IBC-2009 and ASCE7-10
Emax Circuit Breaker is designed, tested, and constructed to meet/exceed these standards:
 ANSI C37.13 — Low Voltage AC Power Circuit Breakers Used in Enclosures
 ANSI C37.16 — Preferred Ratings, Related Requirements, and Application for Low Voltage Power
Circuit Breakers and AC Power Circuit Protectors
 ANSI C37.17 — Trip Devices for AC and General Purpose DC Low-Voltage Power Circuit Breakers
 UL1066 – Low Voltage AC and DC Power Circuit Breakers Used in Enclosures
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4. © BU 3101 Low Voltage Systems
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Market Segments
The MNS-SG is designed to meet the most
stringent industry requirements in the
following markets:
 Oil and Gas
 Mining and Metals
 Utility and co-generation
 Steel Mill
 Pharmaceutical
 Waste Water
 Semiconductor Manufacturing
 Power Generation
 Food and Beverage
 Aerospace
 Critical Power and Data Centers
 Pulp and Paper
Industrial facilities
Oil and gas
Utilities

5. © BU 3101 Low Voltage Systems
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Equipment Ratings
Rated continuous current 1600, 2000, 3200, 4000A, 5000A
Rated tested maximum voltage (Arc Resistant) 254Vac, 508Vac
Rated voltage (Arc Resistant) 240Vac, 480Vac
Rated tested maximum voltage (Non Arc Resistant)254Vac, 508Vac, 635Vac
Rated voltage (Non Arc Resistant) 240Vac, 480Vac, 600Vac
Phases 3 phase 3 wire, 3 phase 4 wire
Neutral (when required on 4Wire Systems) 100% rated
Frequency 60 Hz
Short circuit current withstand at 480Vac up to 100ka
Short circuit current withstand at 600Vac Non Arc
Resistant
up to 85kA
Bus Bracing up to 100ka @ 480v, up to 85ka @ 600V
Enclosure Rating (Arc Resistant) NEMA 1
Enclosure Rating (Non Arc Resistant) NEMA 1 (with and without Gasketing)
Seismic Ratings IBC2009, ASCE7-10

6. Mechanical Overview
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Roof Flaps
Rear Ventilation Flaps

7. © BU 3101 Low Voltage Systems
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Mechanical Overview-Dimensions
 Width- 23.6” (600mm), 27.6” (700mm,
31.5 (800mm)”, 39.4” (1000mm)
 Depth- 70.87” (1800mm)
• Height-
• Arc-Resistant (top of chimney)
96.1“ (2439.7mm)
• Arc-Resistant w/overhead lifting
device 99.4“ (2524mm)
• Arc-Resistant (top of plenum)
122.1“ (3100.5mm)

8. Mechanical Overview- Frame
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 Heavy duty Galvanized C Channel Steel Profile used for all framing
structure
 Exterior sheet metal is 12 or 14 Gauge Galvanized Painted Steel
 Interior parts are 11 to 14 Gauge Galvanized Steel or Glastic

9. Mechanical Overview- Roof Chimney
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Roof chimney flaps automatically open to safely exhaust pressure
and gasses independent of the arc origination point inside the
switchgear

10. Mechanical Overview- Rear Flaps
© BU 3101 Low Voltage Systems
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• Design uses Rear Flaps for:
• Additional ventilation for Thermal Cooling
• Automatically seals gases and pressure inside the equipment during Arc Fault
• Operator Safety by channeling the gasses away from outside enclosure
• Additional protection of operation and surrounding equipment during Arc Fault
• Flaps can be opened/closed from the outside of the equipment

11. Mechanical Overview- Door Mechanisms
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• Enhanced (3) point latches are provided on front
doors as standard
• Top/Bottom horizontal wireways have 180 degree
locking latching mechanism
• Optional rear doors have (3) point latching
mechanism
Optional Rear Door
Mechanism
Front Door Mechanism

12. Mechanical Overview- Floor Plate
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Floor plate is 14 Gauge Galvanized Steel construction
Floor plate with Control Conduit cover Floor plate with Power Conduit cover

13. Mechanical Overview- Bus Compartment
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 Bus phasing is N A B C top to bottom
 Main distribution bus ampacity is up to 5000A with bus bracing up to 100kA
 Vertical distribution bus ampacity is up to 5000A with bus bracing up to 100kA
 Non-insulated bus is silver plated with optional tin-plating available
 Main bus Splice Plate that slides into final assembly position

14. Mechanical Overview-Cable Compartment
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Mechanical and Compression Lugs
Available

15. Mechanical Overview- Barriers
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 Galvanized Steel and Glastic Barriers
separating Main Bus compartment
from cable compartment
 Vertical Galvanized Steel Barriers
separating cable compartment
sections

16. Mechanical Overview- Grounding
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• Ground bus bar is available with silver,
tin, bare plating
• Door Ground Strap

17. Mechanical Overview- Plenum
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• The optional plenum collects and contains the
exhaust pressure and gasses for safe
channeling to a designated area
• The direction of the outlet flap can be
specified by the customer

18. Electrical Overview- Wiring
 As a standard, all control wiring is #14 AWG SIS
 Control wire for current transformers is #10 AWG SIS
 Potential transformers are #12 AWG
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19. Electrical Overview- Wireway
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 Wireway are location at the top, bottom
and vertically within a section
 The top wireway is 4” (100mm) high
 The bottom wireway is 6” (150mm) high
 Wireway doors are hinged and secured
with quarter-turn latches
Pic of vertical wireway

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Electrical Overview- Emax Power Circuit Breaker
1. Trademark, size of CB
2. Trip unit
3. PB for manual opening
4. PB for manual closing
5. Lever to manually charge
closing spring
6. Label with electrical
characteristics
7. Mechanical device to signal
CB open “O” and Closed “I”
8. Signal for springs charged
or discharged
9. Mechanical indication of trip
10. Key lock in open position
11. Key lock and padlock in
racking-in, racking-out position
12. Racking-in, racking-out device
13. Terminal box
14. Sliding contacts
15. CB position indicator

21. Electrical Overview- Emax Cradle
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1 Sheet steel supporting structure
2 Single Grounding pilers mounted on the
left for E1, E2, and E3 double grounding
pilers for E4 and E6
3 Automatic Safety shutters
4 Terminal support base
5 Terminals
6 Contacts signaling that the circuit breaker
is connected, isolated for test, racked-out
7 Sliding contacts
8 Padlock device for safety shutters
9 Fixing points (4 for E1, E2, E3, and 6 for
E4, E6)

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Electrical Overview- Emax Trip Units
 PR121
 Protection Features Only
 PR122
 Protection Features
 LCD Display
 Current Measurement
 Contact Wear
 Communications option
 PR123
 PR122 Features
 Harmonic Measurements
 Communications option

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Electrical Overview- Instrumentation
 Indicating Lights
 Volt, amp, and watt meters
 Control switches
 Multifunction Metering
 Solid-state Relays
 Surge Protectors
 Test Switches

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Electrical Overview- Transfer Scheme
Main-Tie-Main transfer
scheme (open transition)
 Relay controlled
 Kirk Key Interlock

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Electrical Overview- Communications
 Modbus (Standard)
 Profibus
 DeviceNet
 Ethernet

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Arc Mitigation
 Maintenance Switch
 Provides option to dial
down to a lower
instantaneous setting on
trip unit for performing
instantaneous
 REA Relay Arc Flash System
 Detects an arc anywhere in
the bus compartment and
cable compartment utilizing
long-fiber sensor system,
tripping upstream main
breaker in order to provide
minimal damage to
equipment

27. Arc Mitigation
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• Infrared Windows
• IR cameras are used for thermal
scanning of connections
• Minimizes the exposure to live
conductors
• Quantity and location of the IR
windows are dependent breaker
stacking arrangement

28. Local solutions
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• Low Voltage Switchgear must common Integrations
• GE Multilin Relays (C60´s , SR750, SR 760 , PQM II, Multilin F35..)
• High Resistance Grounding systems (post glover, Startco…etc..)
• MNS-MCC and MNS-SG Bus Transition Sections
• Customized coupling bus sections
• Customized Bus duct incoming
• Customized Transfer Schemes
Many more…

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