2016-07-26 Surge Protectors

I have read about, discussed and experienced how surge protectors work and don’t work, and have written about it before, but Ill try again to explain.

The most egregious thing surge protectors do is take your money. One of the highest, if not the highest profit margin devices in your home is a surge protector. A regular power strip without surge protection may cost ten dollars. The same power strip with surge protection may cost thirty dollars. The difference is the maker added two small coin sized varistors and a few capacitors and/or inductors that cost altogether less than a dollar, and it triples the price of the power strip. Most of the time, surge protection is not needed.

Go to a store and buy a new computer, printer, or similar, and the salesman will try to sell you the surge protector. You tell him no, and he will try to twist your arm, explaining how important it is, etc. You have to be insistent to keep these salesmen from pushing a high profit item on the sale.

A Very Interesting Question
This deserves to be thoughtfully considered. If surge protectors were really necessary, wouldn’t the makers of electrical appliances put them in the appliance? The answer is some have surge protectors or something similar. In the case of switching power supplies, used in computers, and many other things, the power supply makes a lot of electromagnetic interference so the incoming power has to have a filter to keep the interference from going out of the power supply and disturbing other things.

Other appliances don’t need surge protection. Coffee pots, toaster ovens, microwave ovens and other high wattage appliances may put too much load on a surge protector, causing the circuit breaker to trip.

Damage Control
The “overflowing sink” theory that surge protectors are based on is correct, but the actual devices fall far short of the theory. They use a varistor that is the size of a small coin, and there are two, one from line to ground and one from neutral to ground.

There are several problems. One is that after they have absorbed a surge, the heat may damage the varistor and it can no longer do its job. So now you have a power strip with no surge protection. Nothing warns you that this has happened.

Another reason surge protectors may not work is that they need to have a good ground. The surge protector lets the surge go from the power wires to the ground wire. This would work very well if the ground wire from the surge protector’s plug went straight to a ground rod driven into the ground. But it doesn’t. The ground wire goes all the way through your house to the electrical panel, where there is a ground.

To make things worse, many older houses came with two prong outlets. The outlet may have been changed to three prong outlets, with the third ground pin. Sometimes the ground pin is connected to a ground wire that goes all the way back to the electrical panel, and to a good ground. Sometimes the wiring is so old that the ground pin inside the outlet goes nowhere. Sometimes a two prong to three prong adapter is used, with a short green wire that is supposed to be connected to ground. Sometimes the outlet box is not grounded, or sometimes the green wire is not connected to anything. In either case, without a ground, a surge protector cannot protect! So if you want to depend on a surge protector you must make sure that it has a good ground.

The package gives some specification of how many Joules of protection this surge protector has. But that has been determined in some testing laboratory. Have you ever seen or read that lightning behaves like it should in a laboratory? Lightning goes where it wants to, when it wants to. Something the size of a coin doesn’t have a snowball’s chance in hell of stopping a surge from close by lightning.

The package tells you this product is guaranteed with an insurance policy to protect the homeowner. If the surge protector fails and causes your house to burn down, you’re protected. But if you read the fine print, you will find so many restrictions and caveats that it is very unlikely that anyone will be able to collect on the policy. As I said earlier, the insurance may require a proper ground, and your house may not have it.

Finally, the surge protection should not be installed in a power strip. The surge protection should be installed at the main electrical panel where power comes into the house. This must have, and already has, an adequate ground where a surge may go and be safely dissipated. It costs a lot to have an electrician do this, but the surge protector will really do a good job of protection.

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