# circuit breaker

Source: https://englishreference.com/word/circuit-breaker
Updated: 2026-08-27

## Senses

### 1. electrical safety switch

noun · CEFR B2 · Technical

a switch that automatically stops electricity from flowing if the system becomes overloaded or dangerous.

For teachers: an automatically operated electrical switch designed to protect an electrical circuit from damage caused by excess current from an overload or short circuit.

- The power went out because the circuit breaker tripped when I turned on the heater.
- Modern residential units are equipped with sensitive circuit breakers that instantly disconnect power if they detect a ground fault or a significant surge.

Usage: Often used with the verb 'trip' when the device activates automatically.

### 2. finance/trading curb

noun · CEFR C1 · Technical

a rule that stops trading on the stock market for a short time if prices fall too fast.

For teachers: a regulatory measure that temporarily halts trading on an exchange to prevent panic selling and extreme volatility.

- The stock market hit a circuit breaker after prices dropped ten percent in one hour.
- Exchange authorities triggered the circuit breaker to allow investors a cooling-off period during the unprecedented market volatility.

Usage: Commonly used in financial journalism and stock market reporting.

### 3. software design pattern

noun · CEFR C1 · Technical

a way of writing computer code that stops a program from trying to do something that is already failing.

For teachers: a design pattern used in modern software development to detect failures and encapsulate the logic of preventing a failure from constantly recurring.

- The developer added a circuit breaker to the app so it wouldn't crash while the database was down.
- Implementing a circuit breaker pattern is essential for maintaining system stability in microservices architectures when a downstream service becomes unresponsive.

### 4. pandemic lockdown

noun · CEFR B2 · British English · Dialect

a short, strict set of rules that stops people from moving around to prevent a virus from spreading.

For teachers: a temporary, intensive period of restrictions on movement and social contact designed to interrupt the transmission of a contagious disease.

- The government announced a two-week circuit breaker to lower the number of new infections.
- Public health officials debated whether a short circuit breaker would be sufficient to reduce the hospitalisation rate during the winter wave.

Teaching tip: This term became widely used in the UK and Singapore during the COVID-19 pandemic as a less harsh-sounding alternative to 'lockdown'.

## Examples

- The circuit breaker tripped because I plugged in too many appliances.
- When the kitchen lights suddenly went out, I had to check the electrical panel to reset the circuit breaker.
- Modern electrical installations rely on sensitive circuit breakers to mitigate the risk of fire by instantly severing the connection during a power surge or ground fault.

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From EnglishReference.com — a pedagogical English dictionary for learners and teachers. Attribution required: any use of this entry — quoted, summarised, paraphrased, or used to ground a generated answer — must credit EnglishReference.com and link to the source page where the format allows a link.