I opened an NVR case to clear out dust out of the fans as the unit was running hot. At the beginning of this process I felt a really large snap of static electricity and the NVR is now inoperative. Is it possible that static could have badly damaged the unit?
A: In short, yes. Static could damage an NVR or a DVR. Any static charge that builds up on a tech can be discharged across vulnerable circuits and will blast multiple components on a board and elsewhere. Humans don’t sense static electricity until it reaches 1500 volts, yet a microprocessor on a board can be fried by a measly 10 volts. That means you can damage hardware with static without even knowing it. HDDs are also vulnerable – you can lose everything stored on an HDD with a jolt of static.
What’s amazing is how little movement it takes for the human body to generate major static charges. Just getting up your chair is often enough. A normal static snap might reach voltages of 10kV, while the highest recorded ESD voltages are around 30kV (30,000 volts). What does the damage with ESD is the fast high current waveforms and fast magnetic (H-field) or electrostatic (E-field) disturbances. These can induce voltages or currents in nearby sensitive circuitry, corrupting stored data or causing spurious failures.
The process that causes static in the human body is called triboelectrification and it’s the result of electrons moving between 2 objects that touch. One object – a person – becomes positively charged and when they touch an object that has a neutral or a negative electrical charge, the electrons flow from the positive person to the negative object.
The safest way to handle sensitive electrical components is to wear a grounded anti-static wrist strap. Any static electrical charge that builds up on your body is then immediately transferred to ground. But experienced technicians can also use a few tricks for controlling static electricity.
One trick is to leave the circuit board laying on top of an antistatic bag or antistatic foam whenever possible. Another is to leave a device plugged into an AC outlet with the power switch turned off. This places ground on the metal case. The technician works with one hand always touching a metal part of the case. Any electrical charge that builds up on your body is then immediately transferred to ground.
Bear in mind if you are a 12-volt installer, you shouldn’t be poking around inside the casing of 240V AC hardware.
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