Question on Circuit Breakers

[Ahmed_Abozeid]

what does circuit breaker or any electrical protection element in general protects?

upstream or downstream ?

thanx

[RHH · Accepted solution]

Hello @Ahmed_Abozeid ,

Your circuit breakers protect your upstream.
Everything behind the circuit breaker gets protected by the circuit breaker's protection capabilities (Thermal, 30mA Person protection etc.)


If something happes in front of the line of the circuit breaker he may/can only react (according to its protection capabalities) and shut himself off, so your items which the breaker feeds (is in front of) are protected from the electrical error.

In case of 30mA Person protection Earth fault breaker will discontinue its service when he detects an earth fault down its line (behind the breaker) by a person putting a pencil/finger inside a socket (for instance).

Hope this gives you thoughtfull insight.