Which component indicates the keying for a switch in electrical installations?

The SK symbol is used to indicate the keying for a switch in electrical installations. This symbol is part of a standardized system for labeling components in electrical systems, which helps ensure that switches are connected properly and safely. The keying feature is crucial for certain types of switches, especially when multiple similar devices are present, to prevent errors in connections that could lead to malfunction or safety hazards.

In terms of other options, a keyed terminal refers to a physical aspect related to the design of a connector that ensures correct orientation during installation but does not specifically indicate keying in the context of switch identification. A safety lock pertains to devices meant for securing equipment to prevent unauthorized use or injury, which does not directly relate to switch keying. An identification tag serves the purpose of labeling and identifying components but does not denote keying. Hence, the SK symbol is the most precise and relevant option for indicating switch keying.