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Surges

Dr. Emmett Brown: But the only power source capable of generating 1.21 jigawatts of electricity is a bolt of lightning!Back to the Future

Lightning is a force of nature—it will hit what it wants, when it wants, and if that thing is electronic, it will almost certainly be destroyed. But if lightning strikes nearby (a power or phone line near your house, or the ground within a few miles of you), surges will appear on circuits in your home or business. With the proper equipment, you can largely protect your equipment from surge damage.

Surge Protection Features

Surges can appear on any wire (by induction), even if that wire is not connected to others, but the strongest surges usually come from power or telephone lines.

There are three basic techniques for combatting surges:

  • Absorb them: Absorption will be rated in joules and amperes (or amps)—bigger is better for both of these numbers. The surge suppressors we recommend below have absorption ratings of 2200 joules, and 85000 amps.
  • Divert them to ground: This capability will show up as a clamping voltage, and a smaller number is better. The AC surge supressors we recommend below have clamping voltages of 35V above the nominal voltage; the DNET1 data surge suppressors we recommend clamp at 7.5VDC. The best AC surge supressors use sine wave tracking to clamp the right amount at each instant in time.
  • Disconnect the circuit using a circuit-breaker, fuse, or something more exotic. This capability is rated in time (milliseconds, microseconds, or nanoseconds), and a smaller number is better. The surge suppressors we recommend below react in less than 1 nanosecond.

The best surge protectors have all three capabilities, and will be proud of their capabilities—so it should be easy to find the above ratings written on their box.

A few other features are often advertised in surge suppressors:

  • EMI protection: to filter electromagnetic noise from the line,
  • Diagnostic LEDs: to show which aspects of the suppressor are working,
  • Battery backup: A nice feature, but no substitute for good surge protection!
  • Phone line, Coax cable, or Data line protection: All useful, though phone supression can't be used for ethernet (and vice versa). The manufacturer is not likely to put the specifications of this protection on the box, so you may be better off using stand-alone supressors.
  • Insurance: As I mentioned at the beginning of this article, if your house receives a direct hit from lightning, or even a sufficiently strong surge, it's possible for equipment to be damaged even if it is very well surge-protected. This insurance takes care of that eventuality. I have never used this insurance (it's usually less hassle for me to replace the damaged equipment myself) but it might be an important feature for you.

These extra features are all useful, but make sure you have adequate basic surge suppression, then worry about the goodies above.

What to Protect

Your choice of what to protect will likely depend on your experience with surges. If you have a few pieces of equipment destroyed every year—the lightning likes you—it's probably worth it for you to protect most complex electronics in your home. If you've never had a problem, you may want to keep playing the odds.

Regardless of which equipment you decide to protect, you need to ensure that all lines connecting to that equipment are surge-suppressed. That means that all interconnected components need to be plugged into surge suppressors (eg, both your printer and your computer, if you have a cable connecting your printer and your computer), and any external (phone, networking, or video) lines need to have suppressors on them as well.

Battery backup units (a.k.a. UPS) are helpful for computers, mostly to allow you to shut down your computer gracefully (after saving your work!). You can get extra protection by plugging a UPS into a good surge suppressor, but you should not plug a surge suppressor into a UPS.

What Volo Recommends

Every computer or network device, and all connected equipment, should be plugged into a high-quality surge suppressor. It's a good idea to use a separate ethernet surge suppressor to protect the equipment that your Volo connection connects to, as well. If your equipment or suppressor has a separate "ground" connection (most ethernet suppressors do), make sure that is connected to a valid electrical ground—usually, the center screw on an electrical outlet or a metal cold-water pipe.

The "gold standard" of power suppression is the Tripp Lite Iso Bar line. Volo stocks (and uses!) Tripp Lite Iso Bar 4 Ultra supressors at $45 each, Tripp Lite AVR550U battery backup units at $65, and Tripp Lite DNET1 ethernet surge suppressors at $25 each. Give us a call at 367-8656 to order these or other hardware items that we stock, and we'll drop them by your house within a few days.