Schools and churches have several special power quality issues. One of the most interesting involves what is called a power-line carrier system. These are systems which use the power system to carry signals between devices. By far the most common is the centralized clock found in most schools.
Due to transient or harmonic disturbances, it is possible to reset clocks in one part of the facility, while clocks in another continue with the correct time. That can become very confusing!
