Oct 10, 2009, 3:59 PM
Post #11 of 12
A few comments.
Re: [Yaxchibonam] Surge protection for Laptops: 3 to 2 prong adapters
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A surge protector can work without ground, in that it would prevent high voltage between hot and neutral. I think that some surge protectors are actually built with a kind of delta circuit, with three surge protectors, one between each wire to the other two wires. Even if there is no surge protector between hot and neutral, the other two would come into play with a large surge, but less effectively.
A huge problem that few people understand relates to having a device plugged into the phone system (or cable system) and AC power. Imagine if a lightning surge hits the phone system but does not hit AC power. The phone system will be high voltage, AC will be low voltage, parts will be fried. The same happens if a surge hits AC but not phone. However, if the phone system and the AC power go high at the same time, no problem, because there is no large voltage across the device. Same story with cable TV/internet.
So your cable or DSL internet box is vulnerable, but if your laptop uses WIFI instead of a wire to the internet box, it is less vulnerable.
A textbook grounding system in the USA looks something like this:
1. Good ground rod, 8 feet long.
2. Heavy Wire from the neutral coming into the house to the ground rod. This will tend to limit surges on the AC line.
3. A telephone Demarc box with a gas tube protector connected to the ground rod.
4. The cable wire coming into the house has a ground block connected to the same ground.
Everything is referenced to the same ground rod, so no large voltages between AC, cable, and phone. Most people assume that all grounds are the same, which is not at all true, especially when you are talking about surges or radio frequencies. This is a basic misunderstanding held by most people, including many who should know better. A pet peeve of mine.
Of course, if the lightning hits your house or next door, all bets are off.
A friend of mine was having problems with his house in the mountains, blowing devices connected to the phone line. He had spent big money to have whole house surge protection installed, but that did not solve the problem. He looked, and his house telephone demarc box did not have the ground connected to anything! The phone company came out and fixed it, no charge. He installed a gas tube protector at his remote gate, another point where the phone line and the AC power came together. His gate was very remote, so he put in a separate ground for the gate. No problems so far.
Any devices that you use inside your house are band aids if the cables coming into the house are not properly referenced to a common ground. If you reference your surge protector to something that is not a common ground, it could even make things worse.
Isolation transformers are an option if proper grounding is not an option, it depends on how desperate/paranoid you are.
I agree with the others that the wiring in most Mexicans homes is worse than substandard, and demonstrate the lack of knowledge of most Mexicans who claim to be electricians.