Final answer:
Appliance shutoff valves and convenience outlets typically must be installed within a specific code-mandated distance from the appliance they serve, and the standard three-prong plug of a three-hole outlet ensures correct insertion for proper function.
Step-by-step explanation:
The question relates to the installation standards for appliance shutoff valves and convenience outlets as they pertain to their proximity to the appliances they serve. While the exact distance is not given in the provided reference material, typically these valves and outlets should be installed within a range specified by national or local electrical codes (such as NFPA 70: National Electrical Code in the USA), often within a few feet of the appliance for safety and functionality reasons. For example, outlets are usually required to be accessible and located so that the flexible cords can be without strain.
As for three-hole outlets, the standard three-prong plug design ensures that it can only be inserted in one way. This is crucial for maintaining the proper function of the three-wire system, with one prong for live, one for neutral, and one for grounding.