What do the symbols on an electrical switch mean?

[AbdullahS]

Hi All,

I am just trying to understand a circuit but cannot figure out the meaning of the following symbol. Did not get very far from googling electrical symbols.

The symbol is given below. I know it is a switch but what does "x" mean on one of the wires and what do the half sine and square waves mean on the other wire?

Thanks you very much for any help that you can offer.

Regards,
Abdullah

 

[Tom.G]

The 'half sine' and square wave indicate respectively: a Circuit Breaker and a Heater.
The heater is sometimes shown as a resistor symbol as in this drawing.



The "10A" is the circuit breaker trip point rating and the heater indicates the circuit breaker is thermally activated.

As a guess, the X indicates the switch contact that is opened when the breaker trips. This would typically be the Hot lead of the incoming power, as opposed to the Neutral lead.

This general functionality is used as a time-delay trip for loads with high inrush (start-up) current, such as motors. The thermally activated breaker takes a bit of time to heat up and trip, allowing the high inrush current for the short time needed for the motor to get up to speed. If the current stays high, as when the motor is overloaded or fails to start, the breaker heats up, trips, and disconnects from the incoming power.

Cheers,
Tom

 

[AbdullahS]

Thanks Tom!