Short circuit and overload conditions are a bit different but they both pose similar dangers. Read on to see their slight differences.
We know that current flows in a path from point A to B – this is considered one phase. A short circuit occurs when current flow deviates from that path in two different ways: phase-to-phase (direct short) or phase-to-ground (ground fault). When current flows from one phase to another, also known as a direct short, that huge amount of current becomes unrestricted and it goes through the phases extremely quick. This causes the wires to heat up and burn through the insulation. The obvious issue with burning through insulation is the potential for a fire.
On the other hand, when current flows from phase to ground, such as a ground fault, it means the current flowing through that phased wire accidentally encounters a ground phase object. The object could be any metal that’s not intended to touch the phased wire. This path to ground is very dangerous and could cause a fire just as the phase-to-ground short circuit.
Circuit breakers could trip for a few reasons but if you’ve ever plugged in too many appliances all at once in one circuit then this might be due to an overload. Wires all have current ratings to signify how much amperage they can take. When an overload occurs, it means that the load draws current greater than the current (amperage) rating of that wire. This causes the wires to overeat and potentially cause a fire.
The conditions we discussed here are mainly based on residential applications but the foundational concepts apply to commercial / industrial applications as well. For instance, motors have amperage ratings that are not meant to be exceeded. If they were to be exceeded, this causes a motor overload condition, which will cause the motor to overheat and burn out. Same concept and hazards apply.