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Special AC plug


jrm30655

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Once upon a time, years ago, you could buy a plug for homes that didn't have 3 wire wiring.

It had 2 prongs on one side and a green wire with a little clip that went under the screw that held the plate on to ground the plug. The other side had a 3 prong female 110 vt jack that you plugged a grounded cord into.

If anyone has seen one, let me know. Better yet, if you see one, buy it and I'll come get it and make it worthwhile. (Mexican rules: If you see it and want it, buy it because you may never see it again)

I haven't seen one in at least 20 years

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The three prong to two prong adapters are not yet illegal and are readily available in any hardware, big box, grocery store, drug store, etc anywhere in the US. They are not a recommended solution because any appliance that comes with a grounded (3 prong) cord does so for a reason. If the little green tab is connected to a metal box that is grounded safely they work fine. Most folks do not bother and so things like surge protectors that are plugged in using a two prong adapter will not work as they are not grounded properly. Many appliances come with 2 prong and almost always a polarized (one small and one larger prong) cord end. This in attempt to make sure the hot side is interrupted when the switch is turned off. Many outlets and many lamps and similar items that are wired by homeowners are wired incorrectly and danger of shock is increased. For instance a lamp bulb could be turned off at the lamp switch and you could still get shocked when removing the bulb. Here in Mexico many outlets and switches are wired wrong and many three prong outlets actually have no ground wire connected. Before you plug in a computer or TV to a surge protector I would remove the switch plate cover to check to see if the center prong slot has a wire (green hopefully) connected to it. Alan

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The three prong to two prong adapters are not yet illegal and are readily available in any hardware, big box, grocery store, drug store, etc anywhere in the US. They are not a recommended solution because any appliance that comes with a grounded (3 prong) cord does so for a reason. If the little green tab is connected to a metal box that is grounded safely they work fine. Most folks do not bother and so things like surge protectors that are plugged in using a two prong adapter will not work as they are not grounded properly. Many appliances come with 2 prong and almost always a polarized (one small and one larger prong) cord end. This in attempt to make sure the hot side is interrupted when the switch is turned off. Many outlets and many lamps and similar items that are wired by homeowners are wired incorrectly and danger of shock is increased. For instance a lamp bulb could be turned off at the lamp switch and you could still get shocked when removing the bulb. Here in Mexico many outlets and switches are wired wrong and many three prong outlets actually have no ground wire connected. Before you plug in a computer or TV to a surge protector I would remove the switch plate cover to check to see if the center prong slot has a wire (green hopefully) connected to it. Alan

Yep, my house does not have a ground wire. I put a ground rod in and I intend to wire it to that ground wire on the plug.

It is the easiest solution that I can come up with. I could pull the plate and wire it into the ground but then you have a wire hanging out that looks lousy.

I only need a ground in one place and that is on my computer system so that plug adapter should do it.

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Yep, my house does not have a ground wire. I put a ground rod in and I intend to wire it to that ground wire on the plug.

It is the easiest solution that I can come up with. I could pull the plate and wire it into the ground but then you have a wire hanging out that looks lousy.

I only need a ground in one place and that is on my computer system so that plug adapter should do it.

The last statement is not correct and can lead to problems.

I've seen 3 small fires started by following this approach, plus microwave oven "blow up" and a well pump burn up due to adding the "good" earth ground.

Before you wire the safety ground to your ground rod, first check to see whether your CFE neutral "ground" "tierra" "white" wire is actually grounded.

Check the voltage of your CFE neutral line versus your home ground rod. If the CFE transformer is not properly grounded at the pole, then you can see significant voltage between your new home-ground rod and the CFE neutral, which can be a bad thing for several reasons.

1. A voltage difference between your home earth ground rod and CFE neutral means that your ground rod is the lowest point in the whole neighborhood's circuit, which means some current from the WHOLE NEIGHBORHOOD flows backwards in through your homes CFE neutral, with part of the whole neighborhood's current running through your household wires into your ground rod.

As such, you need to have the ground rod placed close to the meter, and have the white and green (neutral and safety ground wires) connected/bonded in your breaker box. Use heavy wire when tying your circuit box grounds to your ground rod.

2. A voltage difference between your earth ground and CFE ground causes some surge protectors and some microwave oven's HV transformers to burn up if you do not have the green (safety ground) and white (CFE neutral) circuits connected together.

When there is a difference between CFE ground (tierra - neutral) and your ground rod, current flows through shunt resistors and noise suppression RC circuits in power supplies, surge suppressors, voltage stabilizers, and power conditioners are NOT designed to handle.

I've seen small voltage differences of 5V - 16V between CFE "tierra" and good earth grounds, due to poor grounding of CFE transformers, but one friends neighborhood had 78V - 105V differences between earth ground rods and the CFE "tierra" ground for over 4 months.

The friend discovered the problem when his well pump (grounded by the copper water supply pipe into ground water) burned up. He got a wicked shock when removing the pump. When the voltage differences are small, it causes some things to over heat and start small fires when you don't expect them.

When the voltage differences are large, the problems of adding a ground rod get larger. The friend also suddenly got wickedly large power bills during the months when CFE had things wired wrong at the transformer. CFE has 3 live 110V lines off each transformer going to customer's homes , while the USA and Canada only use 2 - with USA/Canada using the 3'rd phase of 110V to run street lights etc. Since most US and Canadian electricians only ever see 2 phases, Mexican electricity can confuse them.

In other words, BE SURE YOUR white ground (CFE neutral) and green ground (home ground rod) are solidly connected together. and BE SURE you don't have a voltage difference between CFE ground and your new ground rod.

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