|  | 8.10 | Network Power Supply Issues: Power Line Problems
| 8.10.4 | Sources of surges and spikes
There are numerous sources of electrical surges and spikes. Probably the most common one is a nearby lightning strike. Through induction, a nearby lightning strike can affect data lines. Utility switching operations performed by the local power company can also trigger electrical surges and spikes. Other sources of surges and spikes can be located inside your school, office, or building. For example, when equipment such as elevators, photocopiers, and air conditioners, cycle on and off, they create momentary dips and surges in power.