Most of us have witnessed the short burst of electricity or sparks that often take place when something is unplugged or plugged into an outlet. We may have even experienced a momentary shock from this occurrence. It’s only natural to wonder if these random occurrences are dangerous or matters of concern on some level. However, this is a question that actually has two answers.
Good Sparks
Sparks are a normal occurrence. Much of this can be explained by a simple explanation of how electricity works and what happens when an 
appliance is plugged into an outlet. The electrical system at a residence or business is made up of circuits. On any given circuit there may be many outlets that tie into it. These circuits form a continuous loop. When an appliance is plugged into an outlet there’s a slight interruption when the plug and the outlet connection almost touch. An electrical current can easily bridge this small gap and create a blue spark of electricity. Sometimes the spark is visible. However, regardless of whether the spark is visible or not, this happens every time an appliance is plugged in. This is a normal occurrence because electrical currents run hot on a continuous loop.
Sparks of Concern
Not all sparks are created equal. Although it’s normal to see visible sparks from time to time, there are situations that deserve closer inspection. 
Fortunately, there are tell-tell signs that will let you know if you are witnessing good sparks or dangerous sparks. There are four types of sparks that should be investigated because they could be potentially dangerous:
- Sparks that produce a strong odor
- Yellow or white sparks
- Sparks that lasts a long time
- Very large sparks
These four dangerous scenarios often occur for common yet dangerous reasons. A short-circuit may occur if a hot wire is touching a neutral or ground wire. A hot current can produce enough heat to melt wire sheaths and cause a fire. The same things can happen when there are too many appliances plugged into an outlet. Old outlets pose the same risk because the contacts can wear out over time causing the outlet to produce a current that’s not consistent. This is referred to as electrical arcing. Other situations where sparks can be dangerous include situations where someone has performed an electrical repair without the proper knowledge or certifications.
Moisture
According to Andrew from Electrician Thomastown , There is one other common scenario that should be mentioned-moisture. We all know that water and electricity don’t mix. If there is a leak inside your walls or water has somehow found its way inside an outlet cover, a short circuit or some form of electrical damage can occur. This is another common yet dangerous situation.
Sparking outlets can be hard to gauge when it comes to safety. However, if you know what to look for, it’s easy to differentiate between potentially dangerous situations and harmless ones. Become familiar with what to look for and don’t overload your outlets. Many dangerous situations can be avoided by exercising a little bit of common sense safety.