Baking soda is an effective fire reduction method. However, flour and baking powder are very dangerous around flames. Flour is flammable and it can also conduct electricity. The combination can cause serious injury from electrical shock and worsen the situation by adding fuel to the fire. Baking powder is also not an option as it's also highly flammable. 

First, it is crucial to check your local guidelines or building codes. You should typically have one smoke detector for every floor, bedroom, and kitchen. Another rule of thumb is to install one smoke detector for every 500 feet in a home. Reviewing manufacturing recommendations, especially for interconnected devices, is also a good idea to ensure proper connection and monitoring.

Yes, an electrical fire can start even if nothing is plugged into an outlet. While a correctly functioning outlet poses no risk, a fire can be caused by faulty wiring, damaged outlet components, an overloaded circuit, or other electrical problems hidden behind the walls. If you suspect a fault, immediately turn off the circuit breaker and contact a professional electrician to diagnose and repair the issue.

According to the National Fire Protection Association’s Code NFPA 25 (titled “Standard for the Inspection, Testing, and Maintenance of Water-Based Fire Protection Systems”), private fire hydrants must undergo inspection once per year, with an accompanying flow test and any necessary maintenance performed on the same schedule. Keep in mind that your town, city, or county may adopt more or less strict testing requirements.