Why do you receive a nasty shock from a metallic object like a cylinder for example when the particular object was never plugged to electricity? This is the question I asked a colleague we worked together on the items from which he received the shock. The object is a sub-assembly item and until we add every other component there is no means to plug it to a socket. To confirm his claim I touched one of the stacked item and behold I got a sting!
However when I think over the problem, I concluded that static electric charge built on the stacked items during packaging and strapping with sheet of nylon materials. One item separated from the other by a kind of plastic material and they strapped them while moving hence static build up. For safety before handling the Item, we discharge them by using a metal to bridge them together two at a time and we clearly sees bluish spark. The discharge of this electricity is very dangerous on electronics damaging electronics devices; hospital especially emergency and operating rooms for risk of explosion with anesthetic agents. This is why it is important to prevent it.
And what is this static charge?
Static electricity manifest when two insulators for example; hair and comb; fur and silk; carpet and rubber and lots more rub against each other separated, separating and build up charges resulting in accumulation of positive and negative charges build up. Though there are positive applications elsewhere, this is very serious issues in electronics, hospital and some industries set up like paint and flour. Effects of electrostatic or static electricity are– electric shock, deafening sound, lightning, fire and explosion, damaging to electronics
Other obvious examples and effect of static electricity also known as electrostatics
- Walking along a carpeted floor in the winter in a dry and hot environment will generate enough static electricity to shock you if you touch a door knob or any other conductor like metal object for example.
- Static electricity is much pronounced in lightning bolts (thunderbolts) ripping through the sky with light and sound.
The damaging effects of electrostatic is felt when a charged human body discharges through a sensitive electronics such as computer, ultrasound machine, ECG machine, semiconductor materials and lots more. The damage is of two kinds gradual and instant resulting in intermittent or immediate failure of components, circuit boards and the electronic equipment.
- There is also the danger of fire and explosion if this occurs in Operating Room (Operating Theater) of hospital or any place where volatile anesthetic agent and mixture of chemical is in use. In Operating Room environment, there is risk of fire and explosion due to volatile anesthetic fluids and gases where an anti-static material is not used.
In summary the effects of electrostatic or static electricity are– electric shock, deafening sound, lightning, fire and explosion, damaging to electronics
Is it not wise to guard against the negative effects of static electricity?
Due to devastating effects of ESD, precautions should be taken to prevent it. How do we prevent ESD? To prevent occurrence of ESD, you need to do the following:
- Increase Relative Humidity (RH). Increase moisture. Relative humidity is inversely proportional to static electricity. Low RH results in high static electricity and vice versa. 40% to 60% RH is recommended, where RH is below 40% there is high risk of Electrostatic discharge.
- Use of antistatic mats/carpets, floor, clothing and footwear. You should remove any static electricity from your body before you start building your projects or working on any sensitive electronics to avoid damaging your electronics and components. The best way to do this is to ground yourself to allow any static electricity built up in your body to flow away into the ground. How would you do that? Build your projects, troubleshoot and carry out your repair put on proper conductive wrist wrap which connects to the mat. An anti-static wrist wrap works like a lightning rod, diverting the electricity into the wrist wrap. The mat is permanently connected to the general mass of earth; another way is to strap yourself to the metal chassis of the instruments to ensure you stay at the same potential thus not building up damaging static electricity.
The antistatic mats, wrist straps, floor, clothes, footwear are made of materials with good conductivity. (Anti-static shoes should not be confused with insulating shoes, which provide exactly the opposite benefit — some protection against serious electric shocks from the mains voltage)
This means that you are permanently grounded while you are working which ensures static is not able to collect in your body.