General Information
Introduction
MasterPact™ NW Circuit Breakers are designed to protect electrical systems from damage caused by short circuits. All MasterPact circuit breakers are designed to open and close a circuit manually, and to open the circuit automatically at a predetermined overcurrent setting.
Selection of a dc circuit breaker is based on the type of dc system, the rated voltage, and the maximum short-circuit current at the point of installation. UL® Listed circuit breakers are for use on ungrounded systems rated 500 Vdc (600 Vdc unloaded) or less. IEC Rated circuit breakers are for use on ungrounded, grounded middle point, or grounded negative systems up to 750 Vdc.
Codes and Standards
MasterPact circuit breakers are manufactured and tested in accordance with the following standards:
| Insulated Case Circuit Breaker | IEC Rated Circuit Breaker | IEC Extreme Atmospheric Conditions |
|---|---|---|
| UL 489 (UL Listed to Supplement SC) NEMA AB1 CSA C22.2 No. 5 |
IEC 60947-2 | IEC 68-2-1: Dry cold at –55°C IEC 68-2-2: Dry heat at +85°C IEC 68-2-30: Damp heat (temp. +55°C, rel. humidity 95%) IEC 68-2-52 Level 2: Salt mist |
Circuit breakers should be applied according to guidelines detailed in the National Electrical Code (NEC®) and other local wiring codes.
MasterPact circuit breakers are available in Square D™ or Schneider Electric™ brands.
UL File Numbers:
MasterPact NW: E63335, Vol. 4, Sec. 1
Features and Benefits
100% Rated Circuit Breaker
MasterPact circuit breakers are designed for continuous operation at 100% of their current rating.
Two-Step Stored Energy Mechanism
MasterPact circuit breakers are operated via a stored-energy mechanism which can be charged manually or by a motor. The closing time is less than five cycles. Closing and opening operations can be initiated by remote control or by push buttons on the circuit breaker front cover. An O–C–O cycle is possible without recharging.
Drawout or Fixed Mount, 3-Pole (3P) or 4-Pole (4P) Construction
UL Listed (3P only) and IEC Rated (3P or 4P) MasterPact circuit breakers are available in drawout or fixed mounts.
Field-Installable Accessories
Most accessories are field installable with only the aid of a screwdriver and without adjusting the circuit breaker. The uniform design of the circuit breaker line allows most accessories to be common for the whole line.
Reinforced Insulation
Two insulation barriers separate the circuit breaker front from the current path.
Isolation Function by Positive Indication of Contact Status
The mechanical indicator is truly representative of the status of all the main contacts.
Segregated Compartment
Once the accessory cover has been removed to provide access to the accessory compartment, the main contacts remain fully isolated. Furthermore, interphase partitioning allows full insulation between each pole even if the accessory cover has been removed.
Front Connection of Secondary Circuits
All accessory terminals (ring terminals are available as an option) are located on a connecting block which is accessible from the front in the connected, test and disconnected positions. This is particularly useful for field inspection and modification.
All MasterPact NW circuit breakers are designed with an anti-pumping feature that causes an opening order to always takes priority over a closing order. Specifically, if opening and closing orders occur simultaneously, the charged mechanism discharges without any movement of the main contacts keeping the circuit breaker in the open (OFF) position.
In the event that opening and closing orders are simultaneously maintained, the standard mechanism provides an anti-pumping function which continues to keep the main contacts in the open position.
In addition, after fault tripping or opening the circuit breaker intentionally (using the manual or electrical controls and with the closing coil continuously energized) the circuit breaker cannot be closed until the power supply to the closing coil is discontinued and then reactivated.
Disconnection Through the Front Door
The racking handle and racking mechanism are accessible through the front door cutout. Disconnecting the circuit breaker is possible without opening the door and exposing live parts.
Racking Handle and Mechanism
Drawout Mechanism
The drawout assembly mechanism allows the circuit breaker to be racked in four positions (connected, test, disconnected, or withdrawn), as shown in the figure below.
Racking Positions (Cluster Shield Not Shown)
Arc Chamber
Reduced Maintenance
Under normal operating conditions, the circuit breaker does not require maintenance. However, if maintenance or inspection is necessary, the arc chambers are removable to allow visual inspection of the contacts and wear indicator groove (see Contact Wear Indicators for how wear is indicated). The operation counter can also indicate when inspections and possible maintenance should be done.
Operating Conditions
See bulletin 0613IB1202, available in the Schneider Electric technical library, for information on normal and adverse operating conditions.
Ambient Temperature
MasterPact circuit breakers can operate under the following temperature conditions:
-
The electrical and mechanical characteristics are stipulated for an ambient temperature between -13°F (25°C) and 158°F (70°C). Mechanical closing of the circuit breaker (by pushbutton) is possible down to -31°F (-35°C).
-
At altitudes +13,000 ft. (3900 m).
MasterPact circuit breakers have been tested for operation in industrial atmospheres. It is recommended that the equipment be cooled or heated to the proper operating temperature and kept free of excessive vibration and dust. Operation at temperatures above 104°F (40°C) may require derating or overbussing the circuit breaker. See the appropriate instruction bulletin and Correction Factors of this catalog for additional information.
Storage Temperature
Circuit breakers with trip units without LCD displays may be stored in the original packaging at temperatures between -40°F (-40°C) and 185°F (85°C).
For circuit breakers with trip units with LCD displays, this range is -13°F (-25°C) to 185°F (85°C).
Altitude
MasterPact circuit breakers are suitable for use at altitudes of 13,000 ft. (3900 m) and below. See Altitude Correction Factors for altitude correction factors.
Vibration
MasterPact circuit breakers meet IEC 60068-2-6 Standards for vibration.
-
2 to 13.2 Hz and amplitude 0.039 in. (1 mm)
-
13.2 to 100 Hz constant acceleration 0.024 oz. (0.7 g)
Humidity
MasterPact circuit breakers have been tested to the following:
-
IEC68-2-30—damp heat (temperature +55°C and relative humidity of 95%)
-
IEC 68-2-52 level 2—salt mist
The materials used in MasterPact NT and NW circuit breakers will not support the growth of fungus and mold.
MasterPact NW Circuit Breaker Design
| A | Overcurrent Trip Switch (SDE1) | ||
| B | Circuit Breaker Communication Module | ||
| C | Overcurrent Trip Switch (SDE2) or Electric Reset | ||
| D | Cluster | ||
| E | Cradle Rejection Kit | ||
| F | Lifting Tab | ||
| G | Trip Connection to Overcurrent Trip Switch | ||
| H | Auxiliary Control Connection | ||
| I | Shunt Trip (MX2) or Undervoltage Trip Device | ||
| J | Arc Chamber | ||
| K | Shunt Trip (MX1) | ||
| L | Auxiliary Contact Connection | ||
| M | Two Blocks of Four Additional Switches (OF) or Combined “Connected,Closed” Switches (EF) | ||
| N | Block of Four Form C Auxiliary Contacts (OF) | ||
| O | Shunt Close (XF) | ||
| P | Ready-to-Close Contact (PF) | ||
| Q | Charging Handle | ||
| R | Spring-Charging Motor (MCH) | ||
| S | Closing Push Button | ||
| T | Opening Push Button | ||
| U | Operations Counter | ||
| V | Trip Unit | ||
| W | Accessory Cover | ||
| X | Open/Close Push Button Close (Lockable with Padlock) | ||
| Y | Faceplate | ||
| Z | Charged/Discharged Indicator | ||
| AA | Open/Close Indicator | ||
| AB | Push-to-Reset on Fault Trip | ||
| AC | Electrical Close Push Button (BPFE) | ||
| AD | Padlock Attachment | ||
| AE | Key Interlock | ||
| AF | Mounting Plate for Fixed Circuit Breaker | ||
MasterPact NW Cradle Design
| A | Stop Release Button | ||
| B | Padlock Provision | ||
| C | Key Interlock | ||
| D | Door Interlock for Connected Device | ||
| E | Pull-Out Hand Grip | ||
| F | Rejection Feature | ||
| G | Primary Stabs (UL)/Clusters (IEC) | ||
| H | Lifting Tab | ||
| I | Cradle Back Mold | ||
| J | Position Indicating Contact Terminal Block | ||
| K | Overcurrent Trip Switch Terminal Block | ||
| L | Arc Chamber Cover | ||
| M | Tool Shield | ||
| N | Position Indicating Contact Terminal Block | ||
| O | Accessory Control Terminal Block | ||
| P | Auxiliary Contact Terminal Block | ||
| Q | Terminal Cover | ||
| R | Position Indicating Contact Terminal Block | ||
| S | Wiring Cover | ||
| T | Shutter | ||
| U | Racking Interlock for Open Door | ||
| V | Crank Storage Space | ||
| W | Racking Crank | ||
| X | Position Indicator | ||
| Y | Crank Insertion Opening | ||
DC Systems
Selection of a dc circuit breaker is based on the type of dc system, the rated voltage, and the maximum short-circuit current at the point of installation.
The three types of dc systems are:
Distribution System
| Distribution System | Faults | Fault Comments | Worst Case |
|---|---|---|---|
| Isolated Source |
Fault B | Isc
maximum Both polarities (positive and negative) are involved in the fault |
Simultaneous
faults at A and D or C and E Either polarity may be involved at Voltage U. |
| Fault A or C | No consequences | ||
| Faults
A and D or Faults C and E |
Isc
max Either polarity may be involved at voltage U |
||
| Grounded Middle Point |
Fault B | Isc
maximum Both polarities (positive and negative) are involved in the fault |
Fault
B Each polarity may be involved at voltage U/2. |
| Fault A or C | Isc
< Isc maximum at U/2 The negative or positive polarity is involved |
||
| Grounded Negative |
Fault A | Isc
maximum Positive polarity is involved in the fault |
Fault A All poles taking part in breaking must be placed in series on the positive polarity. If the negative polarity is grounded, an additional pole must be provided to be used for isolation of the negative pole but not for breaking. |
| Fault B | Isc maximum Both polarities (positive and negative) are involved in the fault |
Circuit Breaker Connection
Circuit Breaker Connection Based on Distribution System
| Type | Grounded Negative |
Grounded Middle Point |
Isolated Source Only system applicable to UL Listed circuit breakers |
|||
|
Type N (IEC circuit breakers) Type N and H (UL Listed circuit breakers, Isolated Source only) 24 Vdc ≤ UN ≤ 500 Vdc |
Version C |
Version C |
Version C |
Version C1–Split |
||
| Version C1–Series |
||||||
|
Type H 24 Vdc ≤ UN ≤ 500 Vdc |
Version D |
Version C |
Version E |
|||
|
Type H 500 Vdc ≤ UN ≤ 750 Vdc |
Version D |
Version E |
Version E |
|||
|
Type H 750 Vdc ≤ UN ≤ 900 Vdc |
Version D |
Version E |
Version E |
|||
Frame Sizes and Interrupting ratings
Load Diagrams
Version C
Version C1—Split
Version C1—Series
Version D
Version E
Interrupting Ratings for UL 489 Listed MasterPact NW Circuit Breakers
| Model Number (Version C) | Circuit Breaker Rating | Endurance Rating (C/O cycles) (with no maintenance) |
Breaking Capacity* 500 Vdc (max 600 Vdc unloaded) L/R 8 ms |
Breaking Time | Closing Time | |
|---|---|---|---|---|---|---|
| Mechanical | Electrical | |||||
| 800 A | 10,000 | 2800 | 35 kA | 30 to 75 ms |
<70 ms | |
| 1000 A | ||||||
| 1200 A | ||||||
| 1400 A | ||||||
| 1600 A | ||||||
| 2000 A | 10,000 | 1000 | ||||
| 2500 A | 10,000 | 1000 | ||||
| 3000 A | ||||||
| 4000 A | 10,000 | 1000 | ||||
| 800 A | 10,000 | 2800 | 85 kA | 30
to 75 ms |
<70 ms | |
| 1000 A | ||||||
| 1200 A | ||||||
| 1400 A | ||||||
| 800 A | 10,000 | 2800 | ||||
| 1000 A | ||||||
| 1200 A | ||||||
| 1400 A | ||||||
| 1600 A | ||||||
| 2000 A | 10,000 | 1000 | ||||
| 2500 A | 10,000 | 1000 | ||||
| 3000 A | ||||||
| 4000 A | 10,000 | 1000 | ||||
Ratings for IEC 60947-2 Rated MasterPact NW Circuit Breakers
| Circuit Breaker Frame | NW10 | NW20 | NW40 | |||||||
|---|---|---|---|---|---|---|---|---|---|---|
| Circuit Breaker Designation (AIR) | N | H | N | H | N | H | ||||
| Rated Current | In | 1000 A | 2000 A | 4000 A | ||||||
| Circuit Breaker Type | N | H | N | H | N | H | ||||
| Ultimate Breaking Capacity | Icu | L/R ≤ 5 ms | 500 Vdc | 85 kA | 100 kA | 85 kA | 100 kA | 85 kA | 100 kA | |
| 750 Vdc | — | 85 kA | — | 85 kA | — | 85 kA | ||||
| 900 Vdc | — | 85 kA | — | 85 kA | — | 85 kA | ||||
| L/R ≤ 15 ms | 500 Vdc | 35 kA | 85 kA | 35 kA | 85 kA | 35 kA | 85 kA | |||
| 750 Vdc | — | 50 kA | — | 50 kA | — | 50 kA | ||||
| 900 Vdc | — | 35 kA | — | 35 kA | — | 35 kA | ||||
| L/R ≤ 30 ms | 500 Vdc | 25 kA | 50 kA | 25 kA | 50 kA | 25 kA | 50 kA | |||
| 750 Vdc | — | 50 kA | — | 50 kA | — | 50 kA | ||||
| 900 Vdc | — | 25 kA | — | 25 kA | — | 25 kA | ||||
| Rated Service Breaking Capacity (kA) | Ics | % Icu | 100% | 100% | 100% | |||||
| Rated Short-Time Withstand Current (kA) |
Icw | 1 s | 50 | 85 | 50 | 85 | 50 | 85 | ||
| Rated Making Capacity (kA) | Icm | % Icu | 100% | 100% | 100% | |||||
| Break Tme | 30 to 75 ms | 30 to 75 ms | 30 to 75 ms | |||||||
| Closing Tme | < 70 ms | < 70 ms | < 70 ms | |||||||
| Switch Designation (AIR) | — | HA | — | HA | — | HA | ||||
| Rated Making Capacity (kA) | Icm | 85 | 85 | 85 | ||||||
| Rated Short-Tme Withstand Current (kA) |
Icw | 1 s | 85 | 85 | 85 | |||||
| Installation and maintenance | ||||||||||
| Service
Life C/O cycles x 1000 |
Mechanical | Without Maintenance | 10,000 | |||||||
| Electrical | Without Maintenance | 500 Vdc | 8500 | 8500 | 5000 | 5000 | 2000 | 2000 | ||
| 900 Vdc | — | 2000 | — | 2000 | — | 1000 | ||||
Correction Factors
Temperature Correction Factors
| Maximum Ambient Temperature | |||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|
| °F | 140 | 122 | 104 | 86 | 77 | 68 | 50 | 32 | 14 | –4 | –22 |
| °C | 60 | 50 | 40 | 30 | 25 | 20 | 10 | 0 | –10 | –20 | –30 |
| Current | 0.83 | 0.92 | 1 | 1.07 | 1.11 | 1.14 | 1.21 | 1.27 | 1.33 | 1.39 | 1.44 |
Altitude Correction Factors
| < 6600 ft. (2000 m) | 8500 ft. (2600 m) | 13,000 ft. (3900 m) | |
|---|---|---|---|
| Voltage | 1 | 0.95 | 0.8 |
| Current | 1 | 0.99 | 0.96 |
Shipping Weights
Weights for UL 489 Listed MasterPact NW Circuit Breakers
| Frame Rating | Connector Type | Weights (lbs./kg.) | ||||
|---|---|---|---|---|---|---|
| Circuit Breaker | Cradle | Connector | Pallet | Total | ||
| 800–2500 A Drawout | RCTH/RCTV | 109 lbs. (50 kg) | 97 lbs. (44 kg) | 17 lbs. (8 kg) | 17 lbs. (8 kg) | 240 lbs. (109 kg) |
| 800–2500
A Fixed-Mounted |
RCTH/RCTV | 109 lbs. (50 kg) | — | 17 lbs. (8 kg) | 17 lbs. (8 kg) | 143 lbs. (65 kg) |
| 3000–4000 A Drawout | RCTH/RCTV | 109 lbs. (50 kg) | 97 lbs. (44 kg) | 26 lbs. (12 kg) | 17 lbs. (8 kg) | 249 lbs. (114 kg) |
| 3000–4000
A Fixed-Mounted |
RCTH/RCTV | 109 lbs. (50 kg) | — | 26 lbs. (12 kg) | 17 lbs. (8 kg) | 152 lbs. (70 kg) |
Weights for IEC 60947-2 Rated MasterPact NW Circuit Breakers
| Version | Circuit Breaker | Z-Connector | |||||
|---|---|---|---|---|---|---|---|
| NW10DC–NW20DC | NW40DC | ||||||
| Type | Weight | Type | Weight | Type | Weight | ||
| C/D | 3P Fixed | 132
lbs. (60 kg) |
6 lbs. (2.5 kg) |
29 lbs. (13 kg) |
|||
| 3P Drawout | 198
lbs. (90 kg) |
||||||
| E | 4P Fixed | 176
lbs. (80 kg) |
|||||
| 4P Drawout | 264 lbs. (120 kg) |
||||||