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heathesq

Jan 11, 2004, 1:51 PM

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Unknown Electical Problem

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All of a sudden, some circuts have started to fail temporairily and two of them are not carrying enough electricity to make a bulb light fully.

Background:

House is in Chapala. Its about 20 years old and has the standard 2-wire power. I am nearly finished repacing all plugs with a three socket pug including a jump to the ground and soderless connectors instead of tape. It has been raining here about three days and all my problems have occured today.

Someone near us lost all the inside of their house to an electrical fire a few weeks ago. The building did not burn down, but everything in it burned or baked. Don't want to ignore this.

Questions:

Any ideas on what might be causing the problem and how I might fix things? If I get a contractor are there any professional certifications I should look for?

Roger



Rolly


Jan 11, 2004, 3:19 PM

Post #2 of 8 (6547 views)

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Re: [heathesq] Unknown Electical Problem

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Based on your description, my first thought is that rain water has gotten into the conduit and is causing a partial short -- not enough to trip the breaker, but enough to cause problems. To test this idea, turn off everything in the house. Then look at the electrical meter. The wheel should be at a dead stop. If it is still turning, you have a partial short. If it is not moving, water is not your problem. Likely one or more of the new connections you have made are not as good as they appear.

If the problem is rain water, there's likely not a practical solution other than waiting until it dries. Then you will want to find out how the water got in, so you can stop it.

If you want professional help, go to the CFE office and ask them for advice about what to do and who to hire. Try to talk with an engineer, not a clerk at the caja.

Rolly Pirate


Esteban

Jan 11, 2004, 4:35 PM

Post #3 of 8 (6543 views)

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Re: [heathesq] Unknown Electical Problem

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You may also want to check if there is any aluminum wire in the house. Aluminum wire builds up resistance from oxidation. To alleviate the problem, clean all connections and apply a special paste that helps keep the oxidation at a minimum.

If that is not the case, have the electric company check the wiring that goes from the meter to your panel. If the wiring is undersized, it could very well heat up, become brittle and not conduct electricity as it was intended to do.


Papirex


Jan 11, 2004, 9:13 PM

Post #4 of 8 (6529 views)

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Re: [heathesq] Unknown Electical Problem

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I am going to assume that you have checked for water, and aluminum wiring already. If you found aluminum wiring, it is very important that besides coating the ends of the wire with an anti-corrosive compound, that you do not use any of the connections on any outlets, etc. that have the knife-edge connectors. Thatís the type where you just push the end of the wire in it, and the connector grips the wire. You must use outlets that have screw type terminals on them. Aluminum wire requires more surface contact than copper wire does. Aluminum wire doesnít conduct electricity as well as copper wire does. Without more surface contact, there will be more electrical resistance, and a greater possibility of fire.



The next thing I recommend is to check any fuses. This is more important than it would seem to be, here in Mexico. If your house has a breaker panel rather than a fuse panel for all the circuits, it surely has fuses at the meter where the power comes in from the street. Check all the fuses you can find. The fuses used in Mexico are very different from the fuses used north of the border.



Up north, a fuse is either good, or itís blown. If itís blown you replace it. Down here, fuses have replaceable elements in them. After turning off the power, remove a fuse. The fuse will look just like the fuses we are used to seeing up north, but the end caps will unscrew. Remove the end cap and you can see the replaceable element. The elements slide in to a slot in the body of the fuse. The ends of the elements are bent over to hold them in place. The bent ends contact the end caps and provide continuity through the fuse. Sometimes the ends of the elements will burn where they contact the end caps. They will look similar to burned contacts in a switch.



If the ends are burned, clean and/or replace the element and/or the fuse. You can buy replacement elements. All the fuses I have seen have plastic bodies. The cheaper fuses will have plastic male threads in the plastic. The better fuses will have metal male threads attached to the fuse body. They all have metal caps.



Two years ago we had a problem similar to the one you have described. Fluctuating low voltage, brownouts, TV, and stereo dropping out, microwave and refrigerator barely running, etc. Brownouts do more harm than voltage spikes, but they are not as dramatic.



We lived in a court of four houses; the power came in for all four houses at a common location for the meters. None of our neighbors was having any problem. It was driving me nuts, trying to figure out what was going on. It was a three-bedroom house with only two circuits. Get this: there were two 5-amp circuit breakers, they tripped constantly. I replaced them with 20 amp breakers. I didnít want to put higher capacity breakers in because the two circuits were already badly overloaded. It also had been wired with stranded wire, thatís bad news; stranded wire should never be used in house wiring, even though stranded wire is the norm in Mexico.



Our power company here is Luz Y Fuerza, not CFE. They insisted the problem was in the house. I even went so far as to pay for an individual drop from the power pole to serve just our meter. One of the electricians offered to examine the wiring in the house the next day. It was his day off, so of course I was going to pay him. I had done every logical thing I know, with no results, so I figured why not? Two heads are better than one.



The next day while he was checking every thing in the house that I had already checked, he told us that he had attended one of the polytechnic colleges, and had his degree in electricity. Donít ask me what a degree in electricity is, I have a hard time understanding the differences in The Mexican educational system, compared to The U.S.A. He did know what he was doing.



When he wanted to go out to the meter to check the fuses, I had my doubts though. We were getting electricity in the house; that meant the fuses were good. I thought. I was astounded when he opened a fuse, and I saw the badly burned contacts in it. I had never seen a fuse that would come apart. All three fuses had burned contacts in them. Yes, they even fuse the neutral in Mexico; that should never be done. He replaced them all.



Everything seemed to be OK in the house after the fuses were replaced. That night after all the lights were turned on, I noticed we still had some problems, not as bad as before, but noticeable.



I had the electrician come back the next day. He found another set of three fuses in the wall half way down the driveway. They were only about 40 feet from the three fuses at the meter, in the same lines. They were burned too, so he replaced them. Problem finally solved. Why did the original electrician install the second set of fuses? Who knows?



If your fuses check out OK, use a multimeter to check the voltages in the house. If you donít have one, buy one. Start at the meter and keep checking until you find low voltage. You will then know that the problem is between the last point with good voltage and the point where the low voltage begins. There should be no wiring splices in a conduit, but down here, who knows? Be prepared for anything.



I have noticed that most of the tradesmen down here are simply unqualified. You canít just grab a hammer and saw and say you are a carpenter, grab a wrench and say you are a plumber, or grab a pair of pliers and a screwdriver and say you are an electrician. There is quite a bit of mathematics, and knowledge of the applicable laws of physics involved in almost every building trade. It takes several years to master them. Not months, years.



Most people donít know it, but each individual electrician in the U. S. A. must have his own certificate of competency to be able to legally work as an electrician. Individual plumbers must also take a test and have their own individual licenses to be able to legally work in every jurisdiction I have worked in too. Many counties, and cities, require individual plumbing licenses too. A plumber can kill you just as dead as an electrician can. When I lived in California, I had a stack of credit card sized licenses an inch and a half thick. Thatís a lot of annual fees just to work. Iím not referring to a handyman here, but qualified men.



My own qualifications are that I worked for 48 years in the building trades. I worked as an apprentice, journeyman, foreman, general foreman, and as a project manager. I know my way around any building project, from houses to industrial projects. I worked on the construction of The Trans Alaska Pipeline. It was, and is, the largest privately financed construction project in the history of the world.



I mentioned a little about my experience so you will know that I do know how to troubleshoot an electrical problem. I spent a lot of my career working as an industrial instrument technician, and a HVAC technician. I have all my Federal certifications as an air conditioning tech. We used to say, ďChase the power.Ē When you come to a point where the power is interrupted, or erratic, you know that the problem is between the last point where it checked out OK, and where you found the anomaly.



Good luck, Rex








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


Rolly


Jan 12, 2004, 3:18 PM

Post #5 of 8 (6501 views)

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Re: [heathesq] Unknown Electical Problem

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Roger, when you get your problem fixed, please come back here and tell us what it was and how you fixed it.

Thanks,

Rolly Pirate


heathesq

Jan 13, 2004, 11:11 AM

Post #6 of 8 (6480 views)

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Re: [heathesq] Unknown Electical Problem

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Hi Again

Rolly sugested I report when things are all fixed up. Perhaps a progress report would be more useful.

First, some potential problems have been eliminated. I don't have any aluminum wireing, my copper is singloe strand, and my fuses are OK.

Second, the box and breaker are on an outside wall and all the copper has a heavy coating of a gummy oxidation. I have given them a preliminary cleaning, but am going to repeat with CLR.

Third, I may have one of two problems. It could be some of the wireing is decrepit and has minor leaks. Rolly told me how to check that, but the problem cleared up and I can't do anything now. All my plugs read about 133 volts. Alternatively, it might be a problem down the line. An electric company guy was reading meters yesterday and we asked him what might be wrong. Although he spoke in Spanish, I gathered that there was a problem (infernio) upstream from us which was fixed in the early evening. Supporting this alternative is the fact that several people were similarly affected, even those with new wireing, and we all got better at the same time. Not too likely that all of us have crummy wireing.

Fortunately, (irony) we are promised more rain. If my power acts up I will test things like mad and see if I can find what is going on. One thing that puzzels me is why only some circuts were affected. Both affected circuts had heavy kitchen loads, but lights only glowed on these circuts while lights on other circuts were normal. This is what really makes me concerned about my wireing. If it happens again I will plug the fridge and the micorwave in another circut and see if the problem follows them.

Thanks for all the help and advice.

Roger


TomG

Jan 18, 2004, 10:07 AM

Post #7 of 8 (6454 views)

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Re: [RexC] Unknown Electical Problem

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Excellent post.


Esteban

Jan 19, 2004, 8:33 AM

Post #8 of 8 (6435 views)

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Re: [heathesq] Unknown Electical Problem

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One other thing that I have seen several times down here is a wire, embedded in the concrete, even though it's still in conduit, will be touching a piece of rebar in the wall. If you have old metal conduit, the conduit can rust through and/or from the constant expansion and contraction of the different materials a hole will develop in both the conduit and the wire insulation....then again shorts out slowly/sporadically on a piece of rebar. Sometimes you can turn everything off....unplug everything and see if you still have current (using a multimeter).
 
 
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