Forums > Specific Focus > Technical Mexico

Yaxchibonam

Sep 29, 2009, 10:04 AM

Post #1 of 12 (5498 views)

Shortcut

Surge protection for Laptops: 3 to 2 prong adapters

Can't Post |

Need expert advice--I am in Oaxaca, trying to figure out relative safety of buying a a little plastic 3 to 2 prong adapter for my surge protector to charge my Mac laptop. Only the newest buildings in Oaxaca have 3-prong plugs. If I use the little plastic 3 to 2 adapter, does that negate the surge protection? Thoughts? Muchas gracias!
Yaxchi

Rolly

Sep 29, 2009, 10:10 AM

Post #2 of 12 (5489 views)

Shortcut

Re: [Yaxchibonam] Surge protection for Laptops: 3 to 2 prong adapters

Can't Post | Private Reply

Without a clear path to ground, which the 3rd prong is supposed to provide, your surge protector will not work.

Rolly Pirate

arbon

Sep 29, 2009, 11:58 AM

Post #3 of 12 (5466 views)

Shortcut

Re: [Yaxchibonam] Surge protection for Laptops: 3 to 2 prong adapters

Can't Post |

Take the battery out of laptop to charge, and get a spare battery.

( If a suitable charger is available that is )
~~~~~~~~~~~~~~~~~~~~~~~

(This post was edited by arbon on Sep 29, 2009, 12:15 PM)

Yaxchibonam

Sep 30, 2009, 5:58 PM

Post #4 of 12 (5411 views)

Shortcut

Re: [arbon] Surge protection for Laptops: 3 to 2 prong adapters

Can't Post |

OK, so I'm in a pretty hip, pretty modern coffee house in Oaxaca with free wifi, and I walk in and ask for a plug in. They show me a surge protector, like I the one I brought along from the states, and it is plugged into a plastic 3 to 2 adapter, that is plugged into an extension cord, that is plugged into the wall. So when in Rome, I decided to stop worrying about how it SHOULD be done, and go with the way that seems to work. I'm takin' my chances, I know. So far, so good!
Yaxchi

johanson / Moderator

Sep 30, 2009, 6:48 PM

Post #5 of 12 (5401 views)

Shortcut

Re: [Yaxchibonam] Surge protection for Laptops: 3 to 2 prong adapters

Can't Post | Private Reply

Be careful. I am told that a surge protector shunts the surge to the third or grounding wire. If there is no place to shunt the surge to, you are not going to have very good protection should there be a surge.

arbon

Sep 30, 2009, 6:50 PM

Post #6 of 12 (5400 views)

Shortcut

Re: [Yaxchibonam] Surge protection for Laptops: 3 to 2 prong adapters

Can't Post |

You can also buy one of these.

http://1510365blog.files.wordpress.com/...tacle-polarity-2.jpg
~~~~~~~~~~~~~~~~~~~~~~~

johanson / Moderator

Sep 30, 2009, 6:58 PM

Post #7 of 12 (5398 views)

Shortcut

Re: [arbon] Surge protection for Laptops: 3 to 2 prong adapters

Can't Post | Private Reply

I couldn't agree more. I have two, (I'm not sure why I have 2) and I use or lend one of them out quite often helping friends.

It's been a week since I have been up north near where Arbon lives. What happened to the weather. Boy has it gotten cool fast in the lower mainland (lower Western BC) and in Seattle where I also hang out when up north.

Papirex

Oct 10, 2009, 9:29 AM

Post #8 of 12 (5274 views)

Shortcut

Re: [Yaxchibonam] Surge protection for Laptops: 3 to 2 prong adapters

Can't Post | Private Reply

If you can find one, buy an ElectraShield brand surge protector. They are made by TRC corp. http://www.trci.net/ They come in two prong or three prong configuration. They plug into the power cord between it and the power supply/transformer for most laptops. They have a LED on them, and it goes off when a surge occurs, and the unit must then be replaced, they are good for only one surge, because of that, I believe they are probably just a glorified fuse.

I bought one of the two prong models to use with a Gateway laptop at a Radio Shack in Tacoma 3 years ago. I ordered 2 more for spares on the Internet when I got home to Cuernavaca. I don't remember where I ordered them online, Radio Shack does not list them in their online catalog, and TRC does not list them on their website either. I suspect that they may have been discontinued.

I have been trying to find another source for them as I bought a new Compaq laptop this year and it has a three prong power supply. These units are small, and convenient to carry with a laptop for surge protection on the road.

Rex
"The supreme happiness of life is the conviction that we are loved" - Victor Hugo

johanson / Moderator

Oct 10, 2009, 10:55 AM

Post #9 of 12 (5261 views)

Shortcut

Re: [Papirex] Surge protection for Laptops: 3 to 2 prong adapters

Can't Post | Private Reply

When I moved here in 1997, I only had two wire circuits in my house. You know, no third grounding wire. Everyone told me that in order for a surge protector to work well, you need that third wire to shunt the surge to, because if you have only two wires you have something like a fuse which the experts that I talked to say is not as good as having a true ground. (Do I know if that is true? No) So what I did is at the computer was to create a third wire to the now three wire outlet and run it to a 2 meter grounding rod that was outside the window, buried in an area of the yard the was normally watered.

Again, I not an expert on the subject. I just know that it worked when we had a surge several years later. My surge protector shunted the surge to the grounding rod. In fact the surge was so big that I had to replace the surge protector which you don't always have to do when your system is grounded.

Papirex

Oct 10, 2009, 12:28 PM

Post #10 of 12 (5251 views)

Shortcut

Re: [johanson] Surge protection for Laptops: 3 to 2 prong adapters

Can't Post | Private Reply

I did something similar in the first house we leased here, it did not have any grounded electrical outlets. The only practical room to use for my computers was a small room on the second floor, it had originally been a balcony but the owner had it roofed and enclosed. He used it as an exercise room, and he had a hook placed in the new roof/ceiling to hold a punching bag.

I installed a 3 prong outlet to replace the only electrical outlet in the room, and ran a ground wire from it to that metal hook. I checked it with a circuit tester and I had an outlet with hot, neutral, and ground. That was a break for me. Plan B was to run the ground wire down two stories to a grounding stake.

I ended up with an exposed ground wire running up the wall, and across the ceiling for 3 or 4 feet to the hook. I lived with that lash-up for a couple of years. The next couple of houses we have leased here, I always look to see if there are three pronged electrical outlets, and I carry my little circuit tester with me when I look at them to test a couple of the outlets to make sure that the “electricians” here did actually wire the house with a ground wire and didn't just use the three prong outlets for looks.

The house we are living in now was new when we leased it. After we moved in, I checked all of the outlets with my circuit tester. About 3/4ths of all the outlets had the hot and neutral wires reversed. I had to correct them all. When I installed our telephones upstairs none of them worked. Most of the wires had been crossed and I had to correct the telephone wiring in four bedrooms to get them to work properly.

Thank God I spent 46 years working in the construction industry and I know how to fix things like this. I do not trust any Mexican “tradesman” to be really qualified, some are, but you may not know until it is too late if they aren't.

Rex
"The supreme happiness of life is the conviction that we are loved" - Victor Hugo

raferguson

Oct 10, 2009, 3:59 PM

Post #11 of 12 (5235 views)

Shortcut

Re: [Yaxchibonam] Surge protection for Laptops: 3 to 2 prong adapters

Can't Post | Private Reply

A few comments.

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.

Richard

http://www.fergusonsculpture.com

Papirex

Oct 10, 2009, 8:26 PM

Post #12 of 12 (5213 views)

Shortcut

Re: [raferguson] Surge protection for Laptops: 3 to 2 prong adapters

Can't Post | Private Reply

Very good information Richard. The one meter long grounding rods usually used down here have always seemed inadequate to me. In The US the national electric code mandates 8 foot long grounding rods. They were so long that the electricians used to need to stand on the first few rungs of a ladder to start driving them into the ground with a single jack.

About 8 years ago when there was no high speed Internet service here, everybody was forced to use telephone dial up. At that time, a neighbor had the modem in his computer fried by a lightning strike to the telephone wires in our colonia. I mentioned to him that my modem was OK as I connected it through the 2 RJ11 ports on my un-interruptible power supply. He then looked a little sheepish and said he always wondered what they were for, and now he knew.

At present, I have cable high speed Internet service. The service man that installed it did ground it to one of those little one meter long grounding rods. It is not grounded to the same rod that the house wiring is grounded to, I have never been able to locate that rod, maybe it is under the floor somewhere. At any rate it is better than nothing, and is probably the best I can hope for here.

We live on the mountain here and there are many lightning strikes close by. We lost one very old cordless phone after a lightning and thunderstorm a few years ago. I had a few of the surge protectors for laptops that plug into an outlet, and you plug the laptops power supply and the telephone cable into them, they are about the size of a pack of cigarettes. I am now using them to protect the rest of our cordless phones. So far, so good.

I used to have two Dachshunds in Alaska. They always went bananas during thunderstorms. The two Maltese (miniature Poodle) dogs in our family now get a little nervous during thunderstorms, but they don't panic. Maybe Mexican dogs are more thunder-tolerant than American dogs are. They do always let me know that a storm is coming before I hear the first thunderclap.

Another thing that bothers me here is that the “electricians” like to use small gauge stranded wires because they are easier to work with. The fact that small gauge wiring is more dangerous is unknown to them.

I did meet one qualified electrician locally, I had him do some electrical work for me and we talked a lot about our respective trades. He got his training in The United States. He drives a taxi. He told me none of the local electrical contractors want to pay him what he is worth. When a man can make a better living driving a taxi than working as an electrician, that says volumes about how little qualified tradesmen are valued here.

Rex
"The supreme happiness of life is the conviction that we are loved" - Victor Hugo