ABB Low Voltage FAQ

Frequently Asked Questions For ABB EMAX Circuit Breakers

ABB 3/15/2018
Frequently Asked Questions For ABB EMAX Circuit BreakersQ: What is the temperature rating on the EMAX circuit  breaker?
A: The base rating on all EMAX circuit breakers is 40 degrees Celsius. However, they can  operate at higher temperatures in certain installation conditions, breaker types and frame sizes. For example, the EMAX E1, 800 A frame breaker can operate under full load up to 70 degrees Celsius. The EMAX E3, 1600 A frame breaker can also operate under full load up to 70 degrees Celsius. Charts are available for selecting the right breaker for a given application.

Q: Can an electrically operated breaker be mechanically closed after an electrical trip?
A: Yes. As long as there is no electrical trip signal to the breaker, it can be mechanically charged and closed locally. This assumes that the reason for needing to use this procedure is loss of control power. No circuit breaker that has opened under  a fault condition should be re-closed until the operator has determined that the fault has been cleared.

Q: Can I upgrade to a trip unit with more features at a later date?
A: Yes. The EMAX breaker offers a wide range of field-installable trip units with upgrades to include communications ability, power metering and power quality monitoring. Simply remove the existing trip unit and replace it with the new one.

Q: Are the EMAX power circuit breakers suitable for reverse feeding?
A: Yes. All ABB power circuit breakers and molded case circuit breakers are suitable for reverse feeding.

Q: Can I change my breaker from mechanically operated to electrically operated in the  field?
A: Yes. The EMAX electrical accessories are listed for field installation and were designed with this modification in mind. All internal accessories are pre-wired and terminated with plug-in connectors for quick and easy installation. Most accessories also operate on both AC and DC voltages.

Q: Are EMAX circuit breakers 100 percent rated?
A: Yes. EMAX power circuit breakers are listed in accordance with UL Standard 1066 and  ANSI C37 for use at their rated continuous current.

Q: Can the shunt trip and closing coil accessories be continuously powered?
A: Yes. The shunt trip and closing coils of the EMAX circuit breakers can be continuously powered without damaging the device.

Q: Does the  draw-out version of the EMAX circuit breaker require maintenance/adjustment of the spring tension on the terminal jaws?
A: No. The ABB EMAX is constructed with heat treated steel leaf springs within the fixed cradle. These springs permanently maintain the required tension on the jaw connections.

Q: Can EMAX circuit breakers of different sizes be mechanically interlocked?
A: Yes. With the standard cable interlocking systems all frame sizes of the EMAX circuit breakers can be mechanically interlocked. As well as interlocking all frames, the cable interlocks can also interlock fixed breakers with withdrawable breakers. Separately, adapters for Kirk key locks are also available.

Q: The EMAX breakers come with 2A/2B auxiliary contacts. Can they be reconfigured?
A: Yes. All auxiliary contacts provided with the EMAX circuit breakers can be reconfigured for either normally open or normally closed operation.

Q: Can I rack the breaker in and out of the connected position with the door closed?
A: Yes. Although the front of the breaker is accessible with the door closed, the racking rails and components are behind the door when it is closed. This allows the operator to rack the breaker  in and  out with the door securely fastened.

Q: Is the EMAX breaker insulated case or molded case?
A: Neither. The EMAX breaker is an air power circuit breaker.

Q: Is there an extensive spare parts requirement for the EMAX breaker?
A: No. The fixed parts for withdrawable circuit breakers are common to each model, irrespective of the rated current and interrupting capacity. This commonality of parts minimizes the need for an extensive spare parts inventory.

Q: Can I get additional auxiliary contacts to interface with my existing control scheme?
A: Yes. The EMAX breaker has many options for added contact configurations.
Q: Why remove a vintage low voltage power circuit breaker and install a roll-in replacement?
A: See below for many reasons:
• Safety: Older power circuit breakers from various manufacturers often contain asbestos arc chutes and are now an environmental liability and safety issue with maintenance personnel.
• Parts: Original manufacturer’s replacement parts for vintage circuit breakers may no longer be available. The used equipment market may no longer be able to supply dependable parts. Purchasing used parts may be buying another person’s problem.
• Application Change: Power circuit breakers are being asked to do more than ever before. Some have been pressed into service for motor starting duty and other repetitive operational requirements. Others are operated beyond the rating limits of the original designs.
• Minimum Feeder Outage: With roll-in replacement circuit breakers, a feeder outage is reduced to the time it takes to remove the existing breaker from the cell and rack in the replacement breaker. No need for a complete bus outage.
• Lower Operating Cost: Older circuit breakers require continual maintenance and repetitive refurbishing in order to preserve reliability and avoid unexpected downtime. ABB low voltage replacement breakers are virtually maintenance-free,  provide enhanced performance and reliability, and offer a cost effective option to complete switchgear replacement.
• Microprocessors: Today’s technology can provide event marking and data storage, communication with SCADA and DCS systems, self- diagnostics, measurements and more. Maintenance personnel can interrogate the circuit breaker locally or remotely to determine contact wear, peak load, etc.