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simon

Jan 3, 2006, 10:37 AM

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Wiring Colors

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Hello, I am putting in some new lighting in our home in Queretaro, replacing some of the old exposed bulbs. I find that there is a bunch of of wiring colors in these boxes, mainly black, red, white with an occational blue. None of which seem to be consistantly used. Im familar with color standards in the US, but is there one here in Mexico. Is there a color generally designated for hot, neutral and ground.

Thanks!

Scott

Papirex

Jan 3, 2006, 1:52 PM

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Re: [simon] Wiring Colors

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I’m not certain if there is a color code or any electrical code in Mexico, if there is it is certainly not followed and there is zero enforcement. It is a certainty that many if not most of the “electricians” here are self trained handymen, and not true mechanics. I have run into a very few that were very competent, however they are in the minority. It is prudent to assume that no electrical codes have been followed, and check the wiring out yourself with a multi-meter. It’s a pain in the neck to trace all the wiring out, but it is usually the only way you can be sure of what you’ve got.

We moved into a new house 4 years ago. We are the first occupants. The builder bragged about what a good electrician he had, it was one of his sons. About a month after we moved in, I checked the wiring out. Over half of the power receptacles had the hot and neutral wires crossed. Many of the “electricians” here figure that if a light bulb burns, or a TV or refrigerator runs, it is unimportant in which direction the electricity flows.

There is one outlet in our kitchen that I could not correct. The “electrician” had evidently spliced 2 wires together inside a conduit, and had crossed them in the process. When I corrected the polarity one outlet, the other one was wired backwards, and vice versa. Since we lease this house, I didn't want to start pulling wires out of the conduits to make any more corrections.

I doubt if many of those guys even know what a color code is, and they probably have no idea why wires come in different colors. The first house we lived in here had no grounded outlets. When I commented on it to an “electrician” that was installing some ceiling fans for us, he said “That is not needed, so we don’t install ground wires in Mexico.”

A tip: If you do end up finding wires that are crossed or the wrong color, try to find some “phase tape.” I don’t know if it is available in Mexico. Phase tape is colored electricians tape, but only about 3/8ths of an inch wide. Buy some in several colors; you can then correct the color code by putting a band of phase tape around the end of each wire in the Junction box. Phase tape is not legal for most electrical uses in The US, but I have used it extensively to color code pneumatic control tubing. It is a viable solution here.

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

Rolly / Moderator

Jan 3, 2006, 2:04 PM

Post #3 of 10 (3090 views)

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Re: [simon] Wiring Colors

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There actually is an electrical code and standard wire color codes. They are about the same as the NEC in the USA. But who cares? Certainly not the electricians whose work I have seen. When I was wiring my building projects, I had a hard time getting my helpers to pay attention. I also had a hard time buying wire in colors other than white, red and black even at a large wholesale house.

CFE, bless them, is making headway in getting the service entrances prorerly grounded and the wires from the drop to the meter properly sized. But past the meter, it's often a no man's land.

Rolly Pirate

simon

Jan 4, 2006, 1:25 PM

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Re: [RexC] Wiring Colors

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Thanks for your replies! I noticed too a lot of stranded wire being used in my branch circuits as well. Over the past few days Ive installed a couple of light fixtures and a couple of ceiling fans, all different in terms of wire colors! While I was there I pulled out all of the spliced out of the box and used wirenuts and tape to attach them. It bugs me to see a twisted mass of wire splices insulated by electrical tape along. I must say however, the way the electrician wraped these splices made for a ver solid mechanical connection...

Can you give me some tip on how to trace back the hot and neutral wires.

Thanks again,

Scott

Papirex

Jan 4, 2006, 2:55 PM

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Re: [simon] Wiring Colors

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This may not help you, but I use a little three prong tester that I bought in a hardware store about 25 years ago to test receptacles for ground and correct neutral and hot wiring. I don’t know if you can find one of them here in Mexico. It is about the size of the plug end on an extension cord and has three LEDs on it. There is a diagram on it to interpret the pattern of the LEDs that are lit to determine if the receptacle is wired correctly. There is no brand name on the one I have.

It’s a good idea that you installed wire nuts. I have never seen any electrician use them here. I don’t think they know that they prevent the wires from corroding and causing resistance at the splice because the spring in a wire nut holds the wires together so tightly that oxidation is prevented. Wire nuts didn’t come into widespread use until sometime in the 1950s. Prior to their introduction, all the electricians used to solder all wire splices on all the jobs I worked on.

Stranded wire is not suitable for house wiring, but it is widely used down here. The main problem with it is there is not enough continuous surface contact at the connections. One way to partially remedy this would be to solder all the ends of the wires, before making any connections. This provides a solid surface similar to a solid wire. Removing the stranded wire and replacing it with solid wire would be the best solution.

I’m sure these guys down here never heard of Ohms wheel and don’t have a clue as to how to calculate resistance to properly size the circuits and wires they are installing. In The US all those calculations have already been done, and are in the National Electrical Code.

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

(This post was edited by RexC on Jan 4, 2006, 2:57 PM)

sfmacaws

Jan 4, 2006, 6:55 PM

Post #6 of 10 (3023 views)

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Re: [RexC] Wiring Colors

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Quote

These are commonly sold at RV supply places for checking the circuit before plugging your RV into it. Problem is there are few to no RV supply places in Mexico that I know of. Still, if you have friends coming from the US, they can get you one cheaply at Camping World, online or in the store. Or, go to an RV park and ask around someone may have one they don't use. They are usually orange or yellow and cost under $5.

Jonna - Mérida, Yucatán

simon

Jan 9, 2006, 3:53 PM

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Re: [simon] Wiring Colors

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Thanks all for your replies. I will find one of those phase testers when I return to the States tomorrow. I was just thinking on purchasing a clamp on meter but this would be much much cheaper.

Solder sounds like a good option for the stranded wire issue. I will try that. When I return, I will bring some boxes of romex and lots of other goodies from the US.

I did see that a lot of new construction here in QRO has weatherheads and grounding, something I did not notice before. I must say however that the weather heads extend about 5 or more feet above the roofline and seem to be about 1 to 1.25 inches...The service wire only seems to be no. 8 or 10 so I guess masts of any more size would be overkill. But, electrical loads are not nearly as intense as in the US. I need to keep reminding myself of this.

I also had an opportunity to visit my sister in laws under construction home. Interesting to say the least but I did get a better understanding of the techniques used in running switches and outlets via plastic conduit and junction boxes. There is certainly an attitude about wiring a house that seems careless to me and sometimes downright dangerous. Cabling seems to be done by the construction crew and the end connections are up to the home owner to complete. If this is generally the case, then this may be a reason for so many splice connections in the boxes, perhaps.

Besides getting electrocuted, what is going to burn down in a concrete house, right.

Thanks again for you insights and experiences! Ill keep peeling this onion back!

Scott

Papirex

Jan 9, 2006, 6:17 PM

Post #8 of 10 (2968 views)

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Re: [simon] Wiring Colors

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I wouldn’t recommend using Romex in conduits or buried in masonry, it is not designed or intended to be used in conduits. Romex cable is padded and intended to be installed in a conventional wall made of wood studs or under a floor or in an attic without the need for conduit. If you install Romex cable in a conduit, there is a likelihood that it will overheat. The NEC limits the number of wires that can be run in a given size of conduit to limit the amount of heat generated in them. Running Romex in a conduit would skew their calculations all to hell. If it overheats, you could have problems you don’t want.

When you say “clamp on meter”, are you thinking of an AMP meter? An AMP meter will only measure the amperage passing through a wire. That’s important to know for some applications, particularly if you are checking the AMP draw in appliances or electric motors, but probably not what you need.

I'm editing this because I just happened to think of something. If you are going to be bringing back supplies, be sure to bring one or two fish tapes with you, a 25 foot and a 50 footer. If you have to choose bring at least a 50 foot fish. They are almost impossible to find down here. I had one electrical contractor ask me to bring him one the next time I go north. He said his was stolen, and he can not find one anywhere here.
Rex
"The supreme happiness of life is the conviction that we are loved" - Victor Hugo

(This post was edited by RexC on Jan 9, 2006, 7:32 PM)

Rolly / Moderator

Jan 9, 2006, 6:47 PM

Post #9 of 10 (2961 views)

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Re: [RexC] Wiring Colors

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An even more important reason for not using romex is that it will be hard as hell or impossible to pull through the Mexican red plastic conduit.

Rolly Pirate

Papirex

Jan 9, 2006, 7:28 PM

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Re: [Rolly] Wiring Colors

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Rolly, Right on, I hear ya. (see I was alive during the 70s too.) I have pulled lots of wire and pneumatic control tubing in to conduits. It is often a two man job even pulling it into smooth metallic conduit. One guy is pulling on the fish tape, sometimes needing to use a pair of pliers to grip it with and the second guy is feeding, and pushing on the wire at the other end of the conduit while slathering on the approved electrical wire grease and it still ain’t easy.

I can imagine that it would be possible to get only one Romex cable into the red plastic conduits down here, if you were lucky. I don’t think putting lubricating grease on the fabric covered Romex would be too fruitful. If you could do that, it would provide only three wires in the conduit.

When this house was new I helped the telephone guy pull a single telephone wire into a conduit, we made it, but it weren’t easy. Later I tried to help the cable TV guy pull a TV cable into another conduit. We couldn’t do it. After 2 or 3 hours we gave up. We tried every trick in the book, there was just too much friction to pull the wire into the conduit, we didn't have any lubricant, that might have made a difference. It took surface mounting outside and drilling a hole in the wall to bring the cable into the house. With 48 years of construction experience in The US, I have found that construction methods in Mexico are a real adventure.

I imagine when they were using the older conduit that looks like a reinforced rubber hose it was probably even harder to pull wires into it.

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