Introduction

• The PowerPacT B-frame circuit breakers are designed and certified to multiple standards in order to meet the needs of customers who have global designs or build and sell in regions with various standards. One product can be used and sourced globally.

• B-frame circuit breakers have the smallest footprint in the PowerPacT family of industrial molded case circuit breaker products from Square D™ by Schneider Electric™.

• PowerPacT B-frame circuit breakers are designed to protect electrical systems from damage caused by overloads and short circuits.
  They are available with thermal-magnetic trip units from 15 to 125 A, with a breaking capacity up to 65 kA at 480 Vac and 50 kA at 250 Vdc.

• The B-frame circuit breakers are offered in one-, two-, and three-pole versions in both I-Line and unit-mount constructions. There is also a four-pole version, offered in unit mount construction only, with a 100% protected neutral located in the far left pole. It is used in countries where the neutral is also switched (not typical for USA domestic applications).

• The B-frame product offers a flexible platform in which customer needs for various types of mounting and terminations can be accommodated with simple alterations of the base product. Field installable features and termination variety empower the customer to configure the product to their exact needs for control panel or power panel applications.

• B-frame circuit breakers with thermal-magnetic trip units contain individual thermal (overload) and instantaneous (short circuit) sensing elements in each pole. The amperage ratings of the thermal trip units are calibrated at 104°F (40°C) free air ambient temperature. Per the National Electric Code^® (NEC^®) and the Canadian Electrical Code, standard circuit breakers may only be applied continuously at up to 80% of their rating.

All PowerPacT B-frame circuit breakers are equipped with dual-break rotating contacts that reduce the amount of peak current during a short circuit fault. This reduces the let-through currents and enhances equipment protection.

The moving contact has the shape of an elongated “S” and rotates around a floating axis. The shape of the fixed and moving contacts are such that the repelling forces appear as soon as the circuit reaches approximately 15 times nominal current rating (In).

Due to the rotating movement, repulsion is rapid and the device greatly limits short-circuit currents, whatever the interrupting level of the unit. The fault current is extinguished before it can fully develop. Lower let-through currents provide less peak energy, reducing the required bus bar bracing, lowering enclosure pressure, and delivering improved series or combination ratings.

For let-through energy values, seePowerPacT B-Frame Let-Through Energy Curve.

For peak let-through current values, seePowerPacT B-Frame Peak Let-Through Curve.

PowerPacT B-frame circuit breakers have an over-center toggle mechanism providing quick-make, quick-break operation. The operating mechanism is also trip-free, which allows tripping even when the circuit breaker handle is held in the “ON” position.

Internal cross-bars provide common opening and closing of all poles with a single “ON” position.

All PowerPacT circuit breakers have an integral push-to-trip button in the cover to manually trip the circuit breaker. This should be used as part of a regular preventive maintenance program.

The circuit breaker handle can assume any of three positions: ON, tripped or OFF.

The tripped position provides positive visual indication that the circuit breaker has tripped.

The circuit breaker can be reset by first pushing the handle to the extreme “OFF” position. Power can then be restored to the load by pushing the handle to the “ON” position.

B-frame circuit breakers are manufactured and tested in accordance with the following standards.

Marine Type Approval Certification

PowerPacT B-frame circuit breakers comply with most marine classification companies specifications:

Industrial Control Panels

PowerPacT B-frame circuit breakers are used for various circuit protection and switching functions in industrial control panels.

They serve as an incoming main circuit breaker and control panel disconnect, as branch circuit protective devices for final loads, or as feeder circuit protective devices (often combined with motor starters).

• Suitable for use in UL508 Industrial Control Equipment.

• In compliance with worldwide product standards including UL 489 / CSA C22.2 N° 5 and IEC 60947-2.

• Provide overload and short-circuit protection.

• For installation in universal and process-specific type enclosures.

Many PowerPacT B-frame circuit breaker mechanical and electrical accessories are designed specifically for industrial control panel applications.

Electrical Distribution

PowerPacT B-frame circuit breakers are also used in electrical distribution for building applications. They can be used as incoming main circuit breakers but are more commonly applied in North American distribution equipment for outgoing feeder and branch circuit protection.

PowerPacT B-frame unit-mount circuit breakers are both back-pan and DIN-rail mountable, compatible with all kinds of enclosures.

PowerPacT B-frame circuit breakers are available with the unique I-Line™ plug-on connections. These group-mounted circuit breakers are featured in Square D brand Power-Style™ Switchboards and I-Line Panelboards.

A variety of PowerPacT B-frame circuit breaker accessories are also well suited for electrical distribution applications.

The interrupting rating is the highest current at rated voltage the circuit breaker is designed to safely interrupt under standard test conditions. Circuit breakers must be selected with interrupting ratings equal to or greater than the available short-circuit current at the point where the circuit breaker is applied to the system (unless it is a branch device in a series rated combination). Interrupting ratings are shown on the front of the circuit breaker.

The standard unit-mount and I-Line circuit breakers have sealed trip units and may be reverse fed.

The B-frame circuit breaker complies with the following special ratings:

• HACR rating

• Automatic Molded case Switches are rated 600 Vac Delta (refer to switch table 125 A PowerPacT B-Frame Switches)

• 100% Ratings (Optional)

  
  

  B-frame 15–60 A circuit breakers are UL Listed/CSA Certified to be applied at up to 100% of their current rating. Because of the additional heat generated, the use of specially-designed enclosure and 194°F (90°C) rated wire is required when applying circuit breakers at 100% of continuous current rating. Markings on the circuit breaker indicate the minimum enclosure size and ventilation required. The 194°F (90°C) rated wire must be sized according to the ampacities of the 165°F (75°C) wire column in the NEC. Circuit breakers with 100% rating can also be used in applications requiring only standard (80%) continuous loading.

• Grounded B-Phase Systems (Corner-Grounded Delta)

  
  

  Circuit breakers suitable for 240 Vac corner-grounded circuits are marked Ø1-Ø3.

Impact on Protective Devices

The current in 400 Hz systems have higher losses caused by eddy currents and an increase in the skin effect (reduction in the useful cross-sectional area of conductors). The higher losses cause additional temperature rise in circuit breakers subjected to the higher frequency current. To remain within the rated temperature-rise limits of devices, current derating is required. On circuit breakers equipped with thermal-magnetic trip units, the current rating (In) must be derated and the magnetic trip setting Im must be increased.

Breaking Capacity in 400 Hz, 480 V Systems

Power levels of 400 Hz applications rarely exceed a few hundred kW with relatively low short circuit currents, generally not exceeding four times the rated current.

Thermal-Magnetic Trip Units

Thermal-magnetic trip units require the current rating (In) to be derated and the magnetic trip setting (Im) to be increased.

Shunt Trip (MX) or Undervoltage Trip (MN) Voltage Release at 400 Hz and 440 V

Undervoltage releases (MN) rated 24 Vac/dc, 48 Vac/dc, or 110/130 Vac/dc are 400 Hz compliant with their nominal voltages. For voltages greater than 110/130 Vac/dc, please contact Schneider Electric for additional information.

For all voltages of shunt trips (MX), please contact Schneider Electric for additional information.

Power Loss and Resistance Per Pole

Thermal power loss values are used to calculate total temperature rise in the equipment in which the circuit breakers are installed. The values indicated in the tables below are typical values for a device at full rated load and 50/60 Hz.

• Power Loss per Pole (P/pole) in Watts (W)

  • The value indicated is the power loss at In, 50/60 Hz, for a three-pole or four-pole circuit breaker. Measurement and calculation of power loss are carried out in compliance with Annex G of standard IEC 60947–2.

• Resistance per pole (R/pole) in milliohms (mΩ)

  • The value of the resistance per pole is provided as a general indication for a new device.

  • The value of the contact resistance is determined on the basis of the measured voltage drop, in accordance with the manufacturer’s test procedure.
    NOTE: This measurement is not sufficient to determine the quality of the contacts, i.e. the capacity of the circuit breaker to carry its rated current.

• Calculation of the total power loss

  • Total power loss at full rated load and 50/60 Hz is equal to power losses per pole multiplied by the number of poles.

Circuit breaker type		BD		BG		BJ		BK
Number of poles		1	2-4	1	2-4	1	2-4	1	2
Amperage range (A)		15–125	15–125	15–125	15–125	15–125	15–125	15–30	15–30
UL 489 circuit breaker ratings — 50/60 Hz
UL/CSA/NOM (kA rms)	208Y/120 Vac	25	25	65	65	100	100	100	100
	240 Vac	25	25	65	65	100	100	100	100
	480Y/277 Vac	18	18	35	35	65	65	65	65
	480 Vac	—	18	—	35	—	65	—	65
	600Y/347 Vac	14	14	18	18	25	25	65	65
	125 Vdc	10	—	20	—	50	—	—	—
	250 Vdc	—	10	—	20	—	50	—	—
IEC/EN 60947-2 circuit breaker ratings — 50/60 Hz
Ultimate breaking capacity (Icu) (kA rms)	220–240 Vac	25	25	65	65	65	100	—	—
	380–415 Vac	—	18	—	35	—	65	—	—
	440 Vac	—	18	—	35	—	65	—	—
	500–525 Vac	—	14	—	18	—	25	—	—
	690 Vac	—	—	—	—	—	10	—	—
Service breaking capacity (Ics) (kA rms)	220–240 Vac	25	25	65	65	65	100	—	—
	380–415 Vac	—	18	—	35	—	65	—	—
	440 Vac	—	18	—	35	—	65	—	—
	500–525 Vac	—	14	—	18	—	25	—	—
	690 Vac	—	—	—	—	—	2.5	—	—
Rated insulation voltage	Ui	800 V
Rated impulse withstand voltage	Uimp	8 kV
Rated operational voltage (V)	Ue	240	525	240	525	240	690	—	—
Rated current (A)	In (40 °C)	15–125
Utilization category		A
Suitability for isolation		Yes
Pollution degree		3
Durability operations (Open-Close cycles)(as per IEC947–1 annex K)
Mechanical durability		15000
Electrical durability	240 Vac–In (1P)	10000
	440 Vac–In (2P/3P/4P)	10000
Protection
Overload/short-circuit protection	Thermal-Magnetic	X
Dimensions/ Weight See PowerPacT B-Frame Circuit Breaker Physical Properties
Connections
Connections / Terminations	I-Line™ Connection	X
	EverLink™ Lug	X
	Terminal Nut	X
	Mechanical Lugs	X

PowerPacT B-Frame Circuit Breaker Physical Properties

Property		Unit Mount Circuit Breaker				I-Line Circuit Breaker
		1P	2P	3P	4P	1P	2P	3P
Dimensions mm (in.)	Height	5.39 (137)	5.39 (137)	5.39 (137)	5.39 (137)	9.70 (246.5)	9.70 (246.5)	9.70 (246.5)
	Width	1.06 (27)	2.12 (54)	3.19 (81)	4.25 (108)	1.48 (37.6)	2.98 (75.6)	4.48 (113.8)
	Depth	3.15 (80)	3.15 (80)	3.15 (80)	3.15 (80)	5.17 (131.3)	5.17 (131.3)	5.17 (131.3)
Product weight		1.0 lbs (455 g)	1.8 lbs (810 g)	2.5 lbs (1140 g)	3.3 lbs (1487 g)	1.2 lbs (560 g)	2.3 lbs (1020 g)	3.1 lbs (1400 g)

An automatic switch can be used to open and close a circuit under normal operating conditions. They are similar in construction to circuit breakers, except that the switches open instantaneously at a factory-set, non-adjustable trip point calibrated to protect only the molded case switch.

Molded case switches are intended for use as a disconnect device only. UL489 requires molded case switches to be protected by a circuit breaker or fuse of equivalent rating. Molded case switches are labeled with their appropriate withstand ratings. The withstand rating of a switch is defined as the maximum current at rated voltage that the molded case switch will withstand without damage when protected by a circuit breaker with an equal continuous current rating.

PowerPacT B-frame automatic switches are available in unit mount versions. They use the same accessories and offer the same connection possibilities as the circuit breaker versions.

Switches are Listed under UL file E103740 and Certified under CSA file LR88980.

The automatic switch can make and break its rated current. For an overload or a short circuit, it must be protected by an upstream device, in compliance with installation standards.

Switch type			BD	BG	BJ
Number of poles			2-3	2-3	2-3
Amperage (A)			125	125	125
UL489 automatic switch withstand ratings - 60 Hz
UL/CSA (kA rms)		208Y/120 Vac	25	65	100
		240 Vac	25	65	100
		480Y/277 Vac	18	35	65
		480 Vac	18	35	65
		600 Vac	14	18	25
		250 Vdc	10	20	50
Durability operations (Open-Close cycles)
Mechanical durability			15000
Electrical durability		440 Vac- In (2P/3P)	10000
Dimensions / Weight / Connections
Dimensions (H x W x D) mm (in.)		2P Unit Mount	5.39 x 2.12 x 3.15 (137 x 54 x 80)
		3P Unit Mount	5.39 x 3.19 x 3.15 (137 x 81 x 80)
Product weight — kg (lb.)		2P Unit Mount	0.77 (1.7)
		3P Unit Mount	1.07 (2.4)
Connections / Terminations		EverLink™ Lug	X
		Terminal Nut	X
		Mechanical Lugs	X

Ii	Rated Current (A)
	15	20	25	30	35	40	45	50	60	70	80	90	100	110	125
Hold (A)	400	400	400	400	400	400	400	480	640	640	800	1000	1000	1000	1000
Trip (A)	600	600	600	600	600	600	600	720	960	960	1200	1500	1500	1500	1500

The Time Current Curves (trip curves) provide the complete time-current characteristics of the circuit breaker when applied on an AC system. When applying thermal-magnetic circuit breakers on DC systems, they retain the same thermal tripping characteristics, but the magnetic trip levels vary. See table for the appropriate DC magnetic hold and trip levels.

Ii	Rated Current (A)
	15	20	25	30	35	40	45	50	60	70	80	90	100	110	125
Hold (A)	460	460	510	510	510	510	510	510	790	900	900	1200	1200	1200	1200
Trip (A)	680	680	800	800	800	800	800	800	1240	1420	1420	1850	1850	1850	1850