
YucaLandia

Nov 11, 2012, 7:47 AM
Post #10 of 18
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Re: [Axixic] Electrical Supply & Wall Socket Info
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Some places have 3 prong plugs but the third is for show and not usually grounded. Most of the store have a 3 pin to 2 pin converters for less than $1 USD. We have the same issues in our area of Mexico, most homes with only 2 prong outlets, or outlets with no consistent connections of the 3'rd (round pin) plug/socket to ground, and line voltages ranging from 115V - 140V. In case you are worried, the 3'rd pin is just a replicate of the tall/wide slot in the outlet. The outlet is still connected to "ground" (actually neutral), even of it has no 3'rd pin (or even if the third plug is not connected). In US codes, the third pin has its own wire, but that wire goes back to the main circuit box and is connected the same ground as the white/neutral wire: both connect to the power company's neutral line. This means that a 3 prong outlet actually has 2 ground wires, that are electrically identical - where the 3'rd prong is just a spare for safety's sake, in case the white (normal ground wire) is accidentally cut. How often is an internal wire inside a wall cut accidentally? How often is a wire gnawed completely through by mice? In 40 part-time years of servicing appliances, I have seen dryer and refrigerator wires chewed through by mice 3 times, but they have not actually cut the wire - meaning the appliance is still grounded. This means that the millions of Mexican homes and businesses that have no duplicate grounds, work fine for decades, as long as amateurs are not playing with the wires in the breaker box or in the walls or in our electronics. Special Note on "Grounding" for Mexico: Big problems often occur here if the homeowner decides to "correct" the "missing ground" problem themselves, by driving in a ground rod outside (or connecting to a metal water pipe) and connecting the 3'rd pins on outlets to their new "ground". CFE does NOT routinely do a good job of connecting their white (neutral aka "ground") to an actual earth ground. In testing over 100 different homes on different transfomers here, I have found that almost none of the "ground" lines are actually grounded: The "ground" / neutral line on Mexican power lines generally floats between 1V - 5V above earth ground. This means that you can cause some electrical devices big problems if you install an actual separate earth ground, and then connect the 3'rd prongs of your outlets (green wire) to the new earth ground. If your neutral/"ground" line from CFE is floating at 5V, then connecting the 3'rd prong to a good earth ground causes an unanticipated voltage difference internally in your 3 prong electrical devices. Sanolec power strips (and some other brands) are notorious for putting some small filtering capacitors and resistors in between the earth ground (green wire) and the line neutral "ground", to help filter out noise. The problem with this is that when CFE has their neutral/"ground" at 5V, then the internal filters in some devices start to pass unintended currents, and they over heat. The Sanolec power strips then get hot enough to melt the plastic cases, and burn out their filtering components. If you feel compelled to connect the 3'rd prongs to an earth ground, then be sure to connect all your neutral lines (white wires) from CFE to your earth ground, to create a common ground through your entire system - to not damage your appliances/devices that have internal filters between the neutral and safety grounds. Sounds good, right? Unfortunately, your home's new earth ground then becomes the earth ground for the entire neighborhood (for all circuits on your transformer that may serve 2-3 blocks) feeding some current from all the homes through your home's new earth ground wire. In addition to Sanolec surge suppressors burning up, I've seen printers cooked and microwave ovens transformers fried by the grounding and voltage issues here. The issues of protecting electrical devices can be solved with a combination of about 3 different protection devices: Line Conditioners or voltage regulators vs. UPS's vs. surge suppressors. Each type of electrical device in our home needs a different type of protection from common issues here in Mexico, which requires way too much space to write in a post. Read more about protecting our electronics at: http://www.yucatanliving.com/...s-in-the-tropics.htm Protecting Electrical Appliances / Electronics in the Tropics. Hint: Some laptop charging units handle the higher Mexican voltages just fine, while others do not. I have seen several Apple laptop computers that overheat with Mexican voltage and ground issues. We advise protecting things that are important to the user, and that protection usually costs at least $75. steve - Read-on MacDuff E-visit at http://yucalandia.com
(This post was edited by YucaLandia on Nov 11, 2012, 9:39 AM)
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