FIELD: electrical engineering.
SUBSTANCE: invention relates to fire-protection electrical equipment and solves a problem of increasing the reliability of protection of electrical network elements from overheating. The problem is solved with a system for protection from overheating of electrical network elements by means of connection between neutral (N) and protective (PE) conductors of normally opened thermo-relays, use of an emergency circuit breaker (hereinafter – ECB), an automatic switch, through which PE is connected, mechanically connected to ECB for simultaneous activation. Thermo-relays are installed near to possible sites of overheating of controlled electrical network elements. Thermo-relays, when overheating, generate leakage current exceeding nominal disconnecting differential current of ECB, as a result of which the network is de-energized. Nominal current of the automatic switch exceeds nominal disconnecting differential current of ECB activation, but does not exceed the maximum current, for which thermo-relay is designed.
EFFECT: use of an automatic switch mechanically connected to ECB for simultaneous activation limits current flowing through thermo-relay, prevents its overheating and possible firing with failure of ECB for any reason.
1 cl, 1 dwg
