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Electrostatic Discharge (ESD) Problems


ESD occurs when two items with dissimilar static electrical charges are brought together. Nature doesn’t like things to be unequal, so static electrical charges will “jump” from the item with more electrons. This jump is seen as an electrical spark and thus is called an electrostatic discharge. ESD can damage electronic components because the several thousand electrons moving through delicate circuit junctions of silicon chips render the chips useless.


Static can be damaging to equipment and uncomfortable for users at the same time. For example, one worker had the habit of walking around the office without shoes. Walking across a nylon carpet in cotton socks created an immense static charge. When he got within 15 centimeters (not a typo) of the keyboard, the static charge jumped from his fingers to the keyboard. This not only caused him considerable pain, but it also burned out one of the horizontal scan rows on the keyboard, destroying it forever. Fortunately, the computer was properly grounded; otherwise, much more damage could have been done.


Properly grounding equipment can prevent static, as can maintaining room humidity in the 40-60 percent range.

Electromagnetic Interference (EMI) Problems


EMI occurs when magnetic fields intersect network or computer cables, causing interference in that cable. Motors and transformers, which are ubiquitous in an office (in air conditioners, heaters, and so on), are a


typical source of EMI. A common mistake is to run network cable through an elevator shaft or through a ceiling that hides a bank of transformers in fluorescent lights.


Finding the source of EMI can be a challenge. The best approach is to follow a cable with an inexpensive compass, noting strong, odd needle movement. When you find the source of the EMI, you can protect the cable against it by either replacing the cable with a shielded cable (or fiber-optic cable, which is immune to both EMI and RFI) or by moving the cable far away from the source of the EMI.

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