Friday, July 06, 2007

Real Power Protection

A colleague of mine challenged my assertion last month that, "there is nothing you can do" to protect your electronic equipment from damage by a lightning strike. I admit, that was a bit of hyperbole. There are things that you can do to provide protection from a lightning strike.

The real point is that most consumers lack the time, money and expertise to identify and implement a plan for protecting some or all of the electronic equipment in their homes from transient power anomalies like those created by a lightning strike.

For anyone who is interested, there is an excellent booklet from the IEEE (Institute of Electrical and Electronics Engineers), "How to Protect Your House and Its Contents from Lightning; the IEEE Guide for Surge Protection of Equipment Connected to AC Power and Communication Circuits."

What can you do?
  • Identify and fix problems with your home's Building Ground(s).
  • Install "whole-house" surge protection devices for all service wires and pipes entering/leaving your home and bond them to the Building Ground.
  • Install "point-of-use" surge protectors between the equipment to be protected and all service wires connected to the equipment.
What's it going to cost? More than you want to spend, I bet.

Proper grounding is the foundation for effective protection for electronic equipment from power surges. Without a well-designed and properly executed Building Ground, and circuits and receptacles all grounded to the electrical panel and the Building Ground, other steps and expenditures to safeguard your electrical equipment may not provide effective protection.

Popular belief holds that electricity, like water follows the path of least resistance as it travels to ground. This is not correct. Electricity follows all paths available — in inverse proportion to the impedance of the paths. Without proper grounding, surges can travel in unexpected ways and propagate throughout your home.

Most, if not all, single-family homes today have problems with electrical grounding.

Grounding problems in older homes arise from the fact that building codes did not require what today is considered proper grounding. In newer homes grounding problems arise if/when electrical contractors do work that does not conform to the code everywhere in the home. Inspectors do not (cannot) catch all code violations.

Even if the electricians do it right, they aren't the only ones wiring homes today. Alarm, cable, phone, and satellite technicians along with DIY homeowners all install electronic equipment and wiring inside and outside the house. None of these people are likely to have the expertise and take the time to properly ground their work. Things like outdoor lights, spas, dog fences, satellite dishes, etc. can all provide pathways for lightning currents to enter homes instead of the ground.
  • "Since the[se] different electronic systems are often interconnected by signal and control wiring, a defect in the lightning protection for one system can allow surges from lightning to propagate to other systems, producing massive damage." (IEEE booklet, pg. 2)

What's a home owner to do!?

There's no quick and inexpensive way to get real protection. But if you have put a lot of money into computers, audio, video, kitchen appliances, and other electronic devices in your home, it might make sense to protect them. The alternatives are to:
  1. Insure your electronic equipment (make sure that you are covered for any and all power related losses) and design and implement an automated, off-site back-up for your data files.
  2. Put a few "point-of-use" surge protectors around the house to give yourself peace of mind and a false sense of security.
  3. Do nothing and hope for the best.
  4. All of the above.

Personally, I'm sort of a #4. My home computers are pretty well backed up. I've got a few point-of-use surge protectors guarding computers and some other electronics. These surge protectors advertise big-money pay-backs if any connected equipment gets damaged. Does that count as insurance? I don't know. I imagine they don't make it easy to collect on damage claims.

Finally there is lots of other equipment in my house that I have done nothing to protect. I am hoping to dodge the surge. I know that this is a false hope, and I cannot say I have peace of mind when it comes to lightning. <SIGH/>

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