Eaton AQB Breaker for Naval and Marine Electrical

Protect naval and marine electrical distribution systems

Table Of Contents
  1. Eaton AQB Breakers
  2. AQB Breaker Series
  3. Eaton ITE and Siemens
  4. AQB Navy Applications
  5. AQB Breaker Families
  6. AQB Nameplate
  7. Legacy ITE vs Eaton
  8. AQB Ratings
  9. Select a Replacement
  10. AQB Part Numbers
  11. Find an AQB Breaker
  12. Eaton AQB Breaker FAQ
  13. Eaton AQB Breaker Glossary

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Eaton AQB Breakers

Eaton AQB Breakers for Navy and Marine Electrical Distribution

Marine and naval electrical distribution systems are the main applications for Eaton AQB breakers. You need to determine the full breaker before determining whether a reconditioned legacy breaker or a factory-new Eaton product is right because AQB ratings, trip patterns, and mounting configurations differ.

AQB Breaker Series

Understanding the Eaton AQB Breaker Series

In naval distribution panels and switchboards, AQB breakers give switching and overcurrent protection. For demanding naval applications, the series has different frame sizes, trip designs, and interrupting ratings.

Unlike a typical commercial molded-case breaker, an AQB type can operate at 500 VAC, 250 VDC, 60 Hz, or 400 Hz. Eaton also has AQB breakers with custom mounting configurations, electronic protection, and preset thermal-magnetic trips.

Eaton ITE and Siemens

Eaton, ITE and Siemens AQB Names Explained

Older ITE AQB circuit breakers are now in service. ITE is the legacy OEM for these breakers, and Eaton is the current AQB manufacturer.

Siemens brand and ITE equipment appear in one catalog classification. Relectric’s Siemens/ITE circuit-breaker catalog includes the AQB-A250F as an ITE breaker frame. This catalog helps you locate an older part. So, a Siemens ITE AQB breaker replacement should be selected from the complete nameplate information rather than the manufacturer category used on a website.

AQB Navy Applications

Where AQB Navy Circuit Breakers Are Used

Shipboard electrical systems, machinery circuits, auxiliary systems, and other naval power applications use AQB Navy circuit breakers. Vibration, space constraints, DC circuits, 400 Hz electricity, and qualification requirements not seen in regular building distribution systems are in maritime electrical installations.

Eaton identifies current AQB products as Navy and Marine molded-case circuit breakers. One published AQB-A101 configuration is a three-pole breaker rated 500 VAC and 250 VDC with separate interrupting ratings for AC and DC service. It’s also listed as compliant with MIL-DTL-17361. Review Eaton’s AQB-A101 specifications.

AQB Breaker Families

Common AQB Breaker Families

The AQB designation covers several breaker families rather than one interchangeable design.

AQB familyGeneral descriptionWhat you should verify
AQB-A50 and A51Smaller shipboard breaker framesAmperage, frequency, mounting and trip
AQB-A100 and A101Breakers commonly found in older naval systemsExact model, suffix, accessories and voltage
AQB-A250 and A253Intermediate-size naval breaker framesTrip unit, interrupting rating and terminals
AQB-A400 and A402Larger insulated-housing shipboard breakersFrame, trip assembly and mounting
AQB-A800 seriesHigher-current shipboard breakersSensor, trip functions and qualification
AQB-A1600 seriesLarge naval-distribution breakersComplete catalog and application data
AQB-L and AQB-LFCurrent-limiting versionsExact frame and interrupting characteristics

Eaton’s Navy-service technical resources include documentation for AQB-A101, AQB-A253, AQB-L253, AQB-L803 and AQB-A1603 breakers.

AQB Nameplate

Understanding the AQB Nameplate

A designation like AQB-A101 identifies the breaker family, but it usually doesn’t identify every product attribute needed for replacement. Breakers in the same family can have different continuous-current ratings, magnetic-trip ranges, accessories and mounting arrangements.

Before searching for a replacement, record:

  • Complete AQB type and catalog number
  • Manufacturer shown on the nameplate
  • Continuous-current rating
  • Number of poles
  • AC and DC voltage ratings
  • Frequency rating
  • Interrupting capacity
  • Trip type and trip range
  • Shunt-trip or auxiliary-switch information
  • Mounting and terminal configuration

Photograph the front and side labels, terminals, mounting and panel identification. Relectric’s guide on identifying a circuit breaker can help you collect the necessary information.

Legacy ITE vs Eaton

Comparing Legacy ITE and Current Eaton AQB Breakers

A current Eaton breaker shouldn’t be seen as a natural drop-in replacement for every legacy ITE AQB model. Product generations differ in trip construction, accessories, mounting bases, connections and qualification details.

Within an AQB-A101 family, Eaton documents different amperage and magnetic-trip ranges. Eaton also has mounting bases identified for use with AQB-A101, AQB-A103, NQB-A101 and NQB-A103 breakers. This shows why mechanical mounting is confirmed along with the electrical ratings.

If the original model is obsolete, your options can include a current Eaton configuration, a professionally reconditioned legacy breaker or replacement. The correct choice depends on the equipment, application and industry standards.

AQB Ratings

AQB Ratings You Need to Verify

Start with frame size and continuous current. The frame identifies the breaker’s general physical and current class, and the trip rating determines how the installed breaker responds to an overload. Matching the frame without matching the trip doesn’t mean you’re done.

Next, confirm voltage and frequency. A 500 VAC marking doesn’t automatically establish suitability for a 250 VDC circuit, and a 60 Hz breaker doesn’t necessarily make it suitable for 400 Hz service. The exact nameplate and OEM documentation must support the application.

Interrupting capacity is just as important. The replacement needs to be capable of interrupting the available fault current at the system voltage. You should also verify whether the breaker uses a non-interchangeable thermal-magnetic trip, an interchangeable trip assembly or electronic protection.

Finally, confirm the required naval or military qualification. A breaker that physically fits may be unacceptable if it doesn’t carry the required compliance or application documentation.

Select a Replacement

How to Select an AQB Replacement

Use this AQB breaker replacement guide as a starting process:

  1. Record the complete breaker nameplate.
  2. Identify the exact AQB frame and suffix.
  3. Verify amperage, poles, voltage and frequency.
  4. Confirm AC and DC interrupting ratings.
  5. Identify the trip technology and settings.
  6. Compare mounting, terminals and physical orientation.
  7. Check shunt trips, auxiliary contacts and locking devices.
  8. Confirm naval qualification and application requirements.

Don’t substitute an AQB breaker based only on amperage or physical dimensions. Relectric’s explanation of circuit-breaker interchangeability shows the need to verify that a breaker is approved and ready for install.

AQB Part Numbers

Example AQB Part Numbers
Part numberAQB typeDescription
AQB-A50AQB-A5050 A, three-pole, 500 V breaker listing
AQB-A100AQB-A100100 A, three-pole, 500 V breaker listing
1244C52G01AQB-A5010 A, three-pole, 500 VAC naval breaker
1244C52G02AQB-A5015 A, three-pole, 500 VAC naval breaker
1244C52G13AQB-A5030 A, three-pole, 500 VAC, 400-cycle breaker
458D509G11AQB-A10115 A, three-pole breaker with dual magnetic-trip ranges
458D509G12AQB-A10125 A, three-pole, 500 VAC and 250 VDC Eaton breaker
5682D24G15AQB-A10150 A, three-pole Eaton naval breaker
315C574G26AQB-A250250 A, three-pole, 400 Hz Eaton naval breaker
AQB-A250FAQB-A250FITE frame listed in the Siemens/ITE catalog

These are identification examples, not universal substitutes. Compare the complete specifications before ordering.

Find an AQB Breaker

Finding an AQB Replacement

Relectric supplies Eaton, Cutler-Hammer and Westinghouse molded-case breakers, obsolete and reconditioned electrical equipment. When getting help, provide the complete part number and clear nameplate photographs.

If you need an AQB breaker, request a quote from Relectric. Including the system voltage, frequency, required interrupting rating, mounting arrangement and application will support the search.

Eaton AQB Breaker FAQ

What is an Eaton AQB circuit breaker?
An Eaton AQB is a specialized circuit breaker used primarily in naval and marine electrical-distribution systems. AQB models are available in different frame sizes, current ratings, trip configurations, voltage ratings and mounting arrangements.
Who currently manufactures AQB breakers?
Eaton is the current OEM for AQB Navy and Marine circuit breakers. Older installed breakers may carry ITE or other legacy markings, so the complete breaker nameplate should be recorded before selecting a replacement.
Why are some AQB breakers identified as ITE or Siemens/ITE?
ITE is a legacy OEM associated with AQB breakers still found in service. Siemens/ITE may appear as a distributor or catalog classification, but that category doesn’t replace the need to verify the manufacturer, AQB type, catalog number and electrical ratings shown on the breaker.
Can a current Eaton AQB breaker directly replace an older ITE AQB breaker?
Not automatically. You must compare the complete AQB type, amperage, poles, voltage, frequency, interrupting rating, trip characteristics, mounting, terminals, accessories and required naval qualifications. Similar frame numbers or physical fit alone don’t establish compatibility.
Are AQB breakers rated for both AC and DC systems?
Some AQB configurations have both AC and DC ratings, but the values and interrupting capacities can differ. An AC rating doesn’t automatically establish suitability for a DC circuit, so use the exact nameplate and OEM documentation for the proposed application.
Can a 60 Hz AQB breaker be used on a 400 Hz system?
You shouldn’t assume that it can. Frequency is an application-specific rating, and the selected breaker must be documented for the system frequency. Verify 60 Hz or 400 Hz suitability from the complete breaker markings and current OEM information.
What information is needed to identify an AQB replacement?
Provide the complete AQB type and catalog number, manufacturer, continuous-current rating, poles, AC and DC voltage ratings, frequency, interrupting capacity, trip type, trip range, accessories, terminals and mounting configuration. Clear photographs of the breaker, labels, connections and equipment are also helpful.

Eaton AQB Breaker Glossary

Term Definition
AQB breaker A specialized circuit-breaker family used primarily in naval and marine electrical-distribution systems.
Catalog number The complete manufacturer identifier used to distinguish a specific breaker configuration, rating and accessory arrangement.
Continuous-current rating The current a breaker is designed to carry continuously under its specified operating conditions.
Frame The breaker’s general physical and current-size classification. The frame designation alone doesn’t identify every trip, rating or mounting detail.
Interrupting rating The maximum prospective fault current a breaker is designed to interrupt safely at a specified voltage and under stated conditions.
Magnetic-trip range The current range associated with the breaker’s instantaneous magnetic response to high fault current.
MIL-DTL-17361 A military detail specification associated with qualified low-voltage shipboard AQB and NQB circuit-breaker types.
Mounting base The hardware or assembly that supports the breaker and establishes its intended mechanical and electrical connection within the equipment.
Thermal-magnetic trip A trip system combining a thermal response for sustained overloads with a magnetic response for high-current faults.