Periodical replacement of breakers

Case example

The breakers used in our systems may cause abnormal overheating.

Cause

The breakers are estimated to become overheated because of an increase in contact resistance due to age deterioration.

Countermeasures

Please replace the breakers every 15 years or so, depending on the usage environment and condition.
If an electric wire or a breaker is found to be discolored when inspecting a control panel, discontinue use immediately and replace the breaker.

Reference: Guidance on replacement of industrial circuit breakers and earth leakage breakers issued from the Japan Electrical Manufacturers’ Association
https://www.jema-net.or.jp/jema/data/2009circuit_breaker.pdf