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/>

Power Protection

I've written before about power outages, surges, brownouts, etc. and the problems they cause for information technology and the people who depend on IT (i.e., everyone). Check it out.

Unfortunately, for political reasons, these problems are not going to be resolved in our lifetimes. So, today I have some practical advice for dealing with one of the power issues that you and I will encounter -- transient fluctuations in power, which are commonly refered to as power surges, spikes and dips. (Spikes contain high voltages but usually last only a few milliseconds, as opposed to longer, but lower voltage power surges.)

Following a thunderstorm which passed through our area last week, our shop experienced a "surge" of repair business (data recovery) from people and businesses whose computers were fried by the storm. How can we help people avoid these catastrophies?

In the United States, the Alternating Current voltage standard oscillates between +120 volts, through 0 volts, to -120 volts at a rate of 60 complete back-and-forth cycles every second.

Power fluctuations outside the norm can happen for many different reasons. For example electrical appliances and equipment cycling on and off can cause transient dips and surges. However, minor fluctuations are not a problem for most modern electrical equipment. For example, all but the cheapest computer equipment has the capability to handle transient power surges. And such equipment handles transient dips in voltage by drawing more current (amps) to deliver constant power (watts).

Placing a surge protector between your electrical equipment and the wall plug generally does you no good, except if your equipment has no ability to handle surges. On the other hand, there's no sure way to know if your equipment has that capability short of opening it up and looking for Metal Oxide Varistors (MOVs) inside (most brand-name and business-grade PCs have MOV's in their power supplies).

Unfortunately, a false sense of security is not the worst-case scenario for connecting your PC, for example, to a surge protector. Depending upon the design of the surge protector, voltage surges and spikes on the phase wire will be dumped to either the neutral or the ground wires or both. Depending upon the size of the spike and local variables like the specs of the premises wiring and the distance to the earth ground, the (diverted) surge may travel to the PC through the neutral or the ground wires. If a diverted surge reaches the PC, bypassing the PC's surge protections, frying the PC, the surge protector ironically will have caused the PC's demise.

In the event of a thunderstorm, where the electrical potential of each lightning bolt may be 100 million volts, and each bolt can carry 50,000 amps of current, it is impossible to predict how currents will flow in the vicinity of a lightning strike.

So, even if your electrical equipment is turned completely off, it may be damaged in a thunderstorm if it is merely plugged in. That is because with all those volts around, the current can arc over the small distances separating the wires inside your surge protector and/or your electrical equipment. And, the spike can travel from anywhere; the air, the earth, the ground wire, the phone line, the cable TV line, the computer network lines, etc. And we're not only talking about the effects of a direct lightning strike. These effects can be caused by a lightning strike on a utility pole miles away or a tree down the block.

In conclusion; how do you protect your valuable electronic equipment from transient fluctuations in power, which are commonly refered to as power surges, spikes and dips? Dips are not a problem. Surges are not a problem. Spikes are a problem and there is nothing you can do about them except to unplug all your equipment in the event of a thunderstorm in your area.

This is an unresonable prescription for most of us. What if we are away from our home or office when the storm hits? Then all we can do is carry insurance to cover our losses if our equipment is fried. Insurance will generally not cover the value of data lost, so, archive your persistent records to permanent media (DVDs) and backup your dynamic files regularly to online, offsite storage.