# How do I calculate the carbon footprint of a miniature circuit breaker?

Canonical: https://senseible.earth/answers/mcb-circuit-breaker-carbon-footprint-per-piece

Add the moulded housing, copper and silver contacts, bimetal strip and coil per breaker with supplier figures. Then add moulding, assembly and calibration testing electricity, and divide by breakers passed, by pole and rating.

## Materials

- Thermoset or thermoplastic housing.
- Copper, silver alloy contacts and bimetal strip.
- Steel springs and rivets.

## Process

- Moulding and press parts.
- Automated or manual assembly.
- Trip calibration and testing, packing.

## Per piece

Report per breaker by poles and current rating. Multi-pole breakers carry more contacts and housing, so report them separately.

## Worked example: miniature circuit breaker unit per piece (one month)

- Electricity: 30,000 kWh x 0.710 = 21,300 kg CO2
- MCBs passed: 200,000
- Plant total: 21,300 / 200,000 = 0.106 kg CO2 per piece
- Add housing and contacts for the full figure

Inputs are illustrative; use your own bills and production records.

## What Senseible does here

Senseible reads the plant's electricity bills (CEA grid factor 0.710 kg CO2 per kWh, CO2 Baseline Database version 21.0) and fuel invoices (IPCC 2006 defaults) into a fingerprinted Scope 1 and 2 record, the plant-level input to a per-unit figure. Bought-in materials go to the supplier evidence trail; product reports are self-declared drafts.

- [Product carbon footprint calculator](https://senseible.earth/calculators/product-carbon-footprint)
- [Electric switch footprint](https://senseible.earth/answers/electric-switch-carbon-footprint-per-unit)
- [Sheet metal stamping footprint](https://senseible.earth/answers/sheet-metal-stamping-carbon-footprint-per-kg)
- [Automobile industry](https://senseible.earth/industries/automobile)

Sources: [GHG Protocol Product Standard](https://ghgprotocol.org/standards), [ISO 14067:2018, Carbon footprint of products (iso.org)](https://www.iso.org), [IPCC 2006 Guidelines, Volume 2 Energy (fuel defaults)](https://www.ipcc-nggip.iges.or.jp/public/2006gl/vol2.html), [CEA CO2 Baseline Database, version 21.0](https://cea.nic.in/cdm-co2-baseline-database/?lang=en)

Last reviewed 2026-10-20.