Circuit Breaker Markings and Compatibility Guide
Identify breaker voltage, interrupting ratings, pole and trip markings, and use panel labeling and classified replacement lists to check compatibility.
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Read the breaker markings
Read the breaker together with the panel’s equipment label and instructions. The handle amperes identify only one part of the device. A replacement decision also needs the exact breaker type, voltage application, equipment compatibility, and applicable interrupting-rating information.
| Mark / field | Meaning | Keep separate |
|---|---|---|
| Ampere rating / trip information | The marked current or identified trip arrangement | Not the conductor ampacity or a general permission to increase breaker size. |
| Voltage rating | The permitted voltage application | Slash ratings and straight ratings require different system checks; they are not interchangeable labels. |
| Interrupting rating | The device’s stated fault-interruption capability at specified conditions | Not its normal load current, and not automatically the complete assembly SCCR. |
| Type / catalog number | The breaker family and exact construction | Similar width, mounting, or brand appearance does not prove compatibility. |
| Pole / trip arrangement | The device arrangement as marked and documented | A handle tie and an internal common-trip mechanism are not the same feature. |
| Application markings | Additional uses where specifically marked, such as SWD or HID | Read the applicable marking and instructions rather than inferring a use from the handle. |
| Terminal markings | Wire range, material, preparation, and connection conditions | Separate from the handle rating and from any connector fitted to another breaker. |
| Classification / replacement statement | An evaluated replacement application with conditions | A classification applies to the specified equipment and list, not every panel. |
Check compatibility
- Record the panel manufacturer, catalog/model number, equipment label, and the permitted breaker types.
- Identify the proposed breaker by its complete type and catalog number, including special features.
- Compare it with the equipment instructions. For a classified replacement, retrieve the classification and the specific compatibility list for that replacement product.
- Check voltage/system suitability, poles, available fault current and interrupting requirements, terminal conditions, and any series-rating restrictions separately.
- Resolve missing or conflicting documentation with the equipment and breaker manufacturers before making a replacement decision.
“It fits,” “it is the same amperage,” and “it is made by the same corporate group” are not equivalent to an equipment compatibility record. This guide does not offer a universal cross-brand replacement chart.
Record unresolved information
Keep a photograph or transcription of the equipment label, the original breaker identification, the proposed replacement, and the applicable manufacturer/listing document. An unreadable label or missing compatibility list is missing information, not an implied approval.
The standard OCPD rating reference answers a different question: which standard ampere rating is listed. Use terminal markings for connection conditions and the existing fault-current screen only within its stated assumptions.
A device marking reference cannot approve a panel modification, establish a listed series combination, or replace an engineering fault-current evaluation.