Avoid overloading by knowing how many circuits a structure has, what rooms those circuits service, the maximum capacity of each circuit and not trying to use more electricity on a given circuit than the maximum output. To discover this information, locate the circuit breaker in a structure. It is usually a rectangular gray panel somewhere within the structure. The breaker has several circuits that are typically labeled to which rooms they apply to as well as the ampere rating.
Modern homes and buildings have dozens of outlets so keeping track of the circuit breaker is vital to avoiding electrical overload. The configuration of these outlets can be strange with circuits typically grouping outlets by rooms but sometimes by walls. If the circuit breaker legend is confusing, test the circuits to make sure which outlets apply to which circuits by turning these breakers off and on at the circuit breaker.
The ampere rating of the circuit typically measures in amps while most electronic devices measure their electrical output in watts. Use the ampere rating to calculate the maximum safe watt load for all electrical devices. Monitor the devices plugged into that circuit and add their total wattage up to discover the total electrical load being put on that circuit. Make sure this load is no larger than the maximum safe load or risk electrical overload or the circuit blowing.