Hand switch (HS)

ISA 5.1-2009

Drawn as

A bubble with "HS" and a number, with an electric (dashed) signal line to the device it operates.

Meaning

Push-button or selector: local start/stop for a motor, open/close for an MOV, a manual ESD push-button (often HS with a solid bar = control room). Field HS buttons are usually on a local control station (local-control-station).

Variants

A solid bar in the bubble means panel/console mounted
ESD push-buttons are sometimes HZ or ESD-PB