Final answer:
In a home that requires eight smoke alarm units, all eight should be interconnected. This is in accordance with safety guidelines which aim to ensure that occupants receive the earliest possible warning in the event of a fire.
Step-by-step explanation:
The question pertains to the number of interconnected smoke alarms required in a home when eight alarm units are needed. While the query about smoke alarms does not directly relate to the information provided about earthquake preparedness in Southern California, it is clear that the question is about safety standards in the household. According to most safety guidelines and codes, such as the NFPA (National Fire Protection Association), if a home is required to have multiple smoke alarms, they should all be interconnected. This means that when one alarm detects smoke and sounds its alarm, all the interconnected alarms will also sound. This interconnection is crucial for the early warning of all occupants in the home, no matter where they are in the house when smoke is detected.
For a home that requires eight alarm units, all eight should be interconnected to ensure that the safety features function optimally, allowing for the maximum possible warning time to evacuate in case of a fire. Therefore, in a scenario where eight alarm units are necessary, all eight alarms must be interconnected.