Forums > Specific Focus > Home, Garden & Construction in Mexico

1 2 View All

robt65

May 7, 2011, 5:22 AM

Post #1 of 29 (4760 views)

Shortcut

USA - Mexico Voltage Differences for Wire Size

Can't Post | Private Reply

Since voltage in Mexico actually differs from the USA (i.e. References to 110V apply to the range from 100V to 160V, (I think Mexico is actually 127V is it not?) and References to 220V apply to the range from 200V to 260V) to me, this would infer a “hotter” electric running through the wire. If that is correct (I believe it is), is 12/2 Romex sufficient (without running “hot”) for interior 110 household wall receptacles? If not, which is a better size wire to use? I have the same questions regarding 220 wiring for dedicated circuits between the electrical panel and the larger appliances such as the AC, large microwave, clothes dryer etc. Is it correct that 220V can actually run as high as 240V? Anyone want to jump in on this one?
Thanks,
Robt65

(This post was edited by robt65 on May 7, 2011, 6:05 AM)

sparks

May 7, 2011, 5:51 AM

Post #2 of 29 (4753 views)

Shortcut

Re: [robt65] USA - MExico Voltage Differences for Wire Size

Can't Post | Private Reply

You have Romex ? It does not pull well if you have the plastic conduit buried in the walls. I used size 12 on individual circuits (in the room), size 10 for log runs and size 8 to the main panel and the 220 outlet panel

All individual wires

Sparks Mexico - Sparks Costalegre

sparks

May 7, 2011, 7:57 AM

Post #3 of 29 (4732 views)

Shortcut

Re: [robt65] USA - Mexico Voltage Differences for Wire Size

Can't Post | Private Reply

If you ask a public question .... then I don't understand the PM's. I'm not an expert and can often learn from other ideas floating around

Sparks Mexico - Sparks Costalegre

Rolly / Moderator

May 7, 2011, 9:12 AM

Post #4 of 29 (4723 views)

Shortcut

Re: [robt65] USA - Mexico Voltage Differences for Wire Size

Can't Post | Private Reply

For 127v service:
#14 for wall receptacles and ceiling light/fans, except
#12 for kitchen receptacles
#10 for long runs and heavy equipment -- pumps, AC, etc
# 8 for service entrance, (CFE to meter to breaker panel) Confirm with CFE

For 3-phase service (so called 220v) Use the size recommended by the manufacturer of the proposed equipment.
And confirm with CFE for service entrance requirements.

Rolly Pirate

chinagringo

May 7, 2011, 9:32 AM

Post #5 of 29 (4718 views)

Shortcut

Re: [Rolly] USA - Mexico Voltage Differences for Wire Size

Can't Post | Private Reply

As I understand matters, you can use #14 for lighting providing the run isn't too long and there is no more that a 15amp breaker on that circuit. If there is a 20amp breaker, then one should use #12. While maybe a bit of overkill, receptacles typically require #12. There is no question that #14 is easier to work with in boxes and electricians would rather work with it.
Regards,
Neil
Albuquerque, NM

sparks

May 7, 2011, 4:24 PM

Post #6 of 29 (4691 views)

Shortcut

Re: [Rolly] USA - Mexico Voltage Differences for Wire Size

Can't Post | Private Reply

Thanks

I used 12 with 20 amps on smaller circuits.
Main runs are max 15 meters using 10
Only have one 220 outlet in bodega/workshop and used 8
Meter breaker (50amp) to main panel is 8

Sparks Mexico - Sparks Costalegre

DavidHF

May 7, 2011, 7:54 PM

Post #7 of 29 (4672 views)

Shortcut

Re: [sparks] USA - Mexico Voltage Differences for Wire Size

Can't Post | Private Reply

C'mon, it's Mexico; use zip cord and no breaker!

johanson

May 7, 2011, 9:18 PM

Post #8 of 29 (4666 views)

Shortcut

Re: [chinagringo] USA - Mexico Voltage Differences for Wire Size

Can't Post | Private Reply

Neil, you're right on as usual, say I freezing to death in Seattle (well not freezing, but its only about 50 F and threatening rain)

Remember folks, that the voltage in Mexico is 127 +/- 10% while in my part of the states it's 120 +/- 5%. That's why I use a voltage regulator for things built to US specifications when I'm in Mexico. But if things are built for Mexico I usually don't bother.

robt65

May 7, 2011, 11:10 PM

Post #9 of 29 (4659 views)

Shortcut

Re: [johanson] USA - Mexico Voltage Differences for Wire Size

Can't Post | Private Reply

Hi johanson,

Since I have been castigated by one responder for sending a PM that couldn't or wouldn't be answered by him, I will put this one out for all to read, instead of sending you a PM. Maybe that poster can learn something, as I also hope to do. I fully well know that while you are not an expert, you certainly have had the experience to answer my particular question, which maybe, many others have not.

I think you brought up a good scenario . . . . . . certainly one I had not considered, and should have. Since many of the appliances, lamps, computers and other electrical devices we own and use, are made in the USA or at least to USA specs, and since the electric voltage does vary considerably from time to time in México, have you found that using a voltage regulator (or limiter) pretty helpful in México residential useage? Which make and model do you use? How is it installed? Did you buy it on line here in Mexico or NOB? What has your experience (pro and con) been, since it has been in use?

Thanks
robt65

(This post was edited by robt65 on May 7, 2011, 11:14 PM)

chinagringo

May 8, 2011, 6:54 AM

Post #10 of 29 (4644 views)

Shortcut

Re: [johanson] USA - Mexico Voltage Differences for Wire Size

Can't Post | Private Reply

Since I have no formal training as an electrician, I can certainly lay no claim to being right. A number of years ago, I did some consulting for a local franchise of a large national home inspection company. My "area" was working with/revising their software programs that generated the inspection reports. In order to fully understand the report requirements, I was forced to learn the inspection process and just how the information reported by the inspectors fit into the report formats. Naturally, electrical was an important segment of the inspection report. Aluminum wire, wrong sized wire for breaker size, improperly wired GFCI circuits, reverse polarity, improperly wired AFCI circuits were the most common reasons for negative flags in the electric portion of the report. Since these issues are deemed a safety matter, they received "red flags" which indicated a critical problem. Real estate agents hated "red flags" since the emphasis didn't allow them to slide over the problem as being minor!

I discussed Robert's questions and issues with him on the phone yesterday and I was definitely remiss in not suggesting the option of using a whole house voltage regulator. That is a great suggestion! I happen to agree with Robert that to err on the side of caution and safety with respect to electricity provides one with a certain peace of mind.
Regards,
Neil
Albuquerque, NM

johanson

May 8, 2011, 11:16 AM

Post #11 of 29 (4618 views)

Shortcut

Re: [robt65] USA - Mexico Voltage Differences for Wire Size

Can't Post | Private Reply

Sure, to have the perfect system, for the perfect house, I would want whole house voltage regulators and surge protectors for each of the one, two, or three phases of that house.

Yes I am well protected from surges, you know grounding wires attached to three 2 meter long rods buried in the ground, and surge protectors, and yes I use voltage regulators on that/those expensive (to me) TV's and satellite receivers but no on my Mexican washer/dryers, micro, refrig, etc.

But I don't need a voltage regulator on my laptop, smart phone,etc for example. Look at the specifications on the AC to DC converter feeding that electronic advice. It says on mine, good for input voltages from 100 to 240 volts at 50/60 cycles.

You pointed out that your lamps are built to US specifications. Yes your incandescent bulbs will burn out faster but simply replace them with compact fluorescents (CFLs), like most everyone is doing both up north and in Mexico. And for some reason CFLs built to US specs seem to work well in Mexico, be the voltage 120 or 127 +.

Where do I buy them? Always at Costco, be I up north or along the shores of Lake Chapala. But they are much cheaper up north where I can buy four 60 watt equivalent CFL bulbs for $3.99 US less a $3 US rebate from my local electric utility (Costco, Seattle) than what I pay when buying at the Guadalajara Costco

robt65

May 8, 2011, 4:53 PM

Post #12 of 29 (4595 views)

Shortcut

Re: [johanson] USA - Mexico Voltage Differences for Wire Size

Can't Post | Private Reply

Hi johanson,

Thanks for the feed back. I was very happy to see someone else other than I using three grounding rods!!!!!!! as lot of others here thought I was crazy to use three such ground rods. No oneupsmanship here, but do to the layout of the land and the rock and a water source deeper than 2 meters I am actually using four such ground rods. Two of the rods are made longer by one screwing into the other for additional length. I have one such spot on my lots, not to faer from the panel location, that will bring it closer to damp earth undergound.

I have a friend in the city of Queretaro that lost all their appliences through a heavy surge. That sure turned out to be pretty expensive for her, not to mention all the food that was wasted from the fridge.

Thanks for the information.

robt65

YucaLandia

May 9, 2011, 3:47 PM

Post #13 of 29 (4563 views)

Shortcut

Re: [robt65] USA - Mexico Voltage Differences for Wire Size

Can't Post | Private Reply

In Reply To

If I've read correctly, then some of your questions haven't been answered. One view is that most "110V" circuits in the States and Canada actually run around 120V and as high as 126V. This means that "127V" in your Mexican home is really not much different than the actual 120V-124V likely present back NOB.

It is worth noting that voltage in Mexico is often not as well regulated as in Canada or the US. Typical voltages in Mexico can run from 105V AC to 138V AC. You seem concerned about having large enough gauge wires due to higher than 110V, but this seems upside down. When the voltage is higher than 110V, the current drawn for the same wattage load is proportionally higher. e.g. A microwave oven rated at 1500W draws roughly 15% lower amperage at 127V (17 amps) versus 19 amps at 110V.

Since the higher voltages in Mexico allow some appliances to function with lower amps, then the wire size needed can actually be smaller for these loads. Note that the opposite is true for simple resistive devices like incandescent light bulbs, hair dryers, and toasters. Still, the 127V Mexican value is basically no different than the typical 120V in USA & Canada.

In all of these cases, the wire specs that Rolly quoted above are very good.

Regarding your question on "220V" in your home here: Since household "220V" is actually just two "110V" legs, provided out of phase, then the actual voltage at your "220V" appliance is the simple sum of your two "110V" legs. Since our neighborhood here in Merida has 133V on one leg, and 137V on the other leg, our "220V" air conditioner actually sees "270V" peak to peak, as measured by both a DVM and O-scope.

This relationship works the same way NOB. Since most NOB homes have 2 legs that are actually at 120V, your "220V" NOB appliances are actually being run at 240V most of the time (mas o meno).

Sidelight: I suspect that you know that the most common problem with electricity here is excessively high voltage (135V and higher) that is notorious for damaging some printers, microwave ovens, etc, and that poor grounding issues seem to account for most of the other damage to electrical gear and electronics.

Best of luck with your projects!
steve
-
-
Read-on MacDuff
E-visit at http://yucalandia.com

(This post was edited by YucaLandia on May 9, 2011, 5:10 PM)

robt65

May 9, 2011, 7:48 PM

Post #14 of 29 (4539 views)

Shortcut

Re: [YucaLandia] USA - Mexico Voltage Differences for Wire Size

Can't Post | Private Reply

Hi Steve,

Thanks for the response . . . . . . You said: “It is worth noting that voltage in Mexico is often not as well regulated as in Canada or the US. Typical voltages in Mexico can run from 105V AC to 138V AC. You seem concerned about having large enough gauge wires due to higher than 110V, but this seems upside down. When the voltage is higher than 110V, the current drawn for the same wattage load is proportionally higher. e.g. A microwave oven rated at 1500W draws roughly 15% lower amperage at 127V (17 amps) versus 19 amps at 110V.”

(This last (Bold / Italic) section or your remark is exactly my argument for a decent size wire for those occasional (and in this part of Mexico) not too infrequent number of times of power surges that cause me to be concerned. For the slight price difference for the protection provided, I think this larger size wire makes good sense. Under the circumstances don’t you agree?

you have given me exactly what I have been looking for (especially regarding the 220) with one exception. I am using a wire size #6 for the juice traveling from the meter base to the house (100 ft (approximately away from the electric panel box. One of my reasoning’s, is that I would suspect (due to distance) some drop in voltage, maybe not significant, but some drop. Do you agree with that surmise? I am also concerned about the size wire between the panel breaker box and hi usage electrical equipment bought in the USA, such as the large microwave, AC's, swimming pool (future project) pump / filter system, or an outdoor Jacuzzi, clothes dryer, gas / electric dual-fuel range with an electric convection oven (commercial grade), etc., I'm thinking that I should use a # 8 wire, with the 220 breaker. Of course the amp size of the breaker would match the amp size plus 10% of the specific electrical unit I was sending power to. What’s your take on the # 8 wire size for that use?

Thanks again Steve for your help.

robt65

robt65

May 9, 2011, 7:52 PM

Post #15 of 29 (4537 views)

Shortcut

Re: [DavidHF] USA - Mexico Voltage Differences for Wire Size

Can't Post | Private Reply

DavidHF,

This is a serious discussion and maybe if you have nothing practical to add, you would'nt mind slideing on over to the cooking section.

thanks,
robt65

(This post was edited by robt65 on May 9, 2011, 8:03 PM)

robt65

May 9, 2011, 8:01 PM

Post #16 of 29 (4535 views)

Shortcut

Re: [YucaLandia] USA - Mexico Voltage Differences for Wire Size

Can't Post | Private Reply

Hi Steve,

You also said: "Sidelight: I suspect that you know that the most common problem with electricity here is excessively high voltage (135V and higher) that is notorious for damaging some printers, microwave ovens, etc, and that poor grounding issues seem to account for most of the other damage to electrical gear and electronics."

This is from a previous thread on this post . . . . "I was very happy to see someone else other than I using three grounding rods!!!!!!! as lot of others here thought I was crazy to use three such ground rods. No one-upmanship here, but do to the layout of the land and the rock and a water source deeper than 2 meters I am actually using four such ground rods. Two of the rods are made longer by one screwing into the other for additional length. I have one such spot on my lots, not to far from the panel location, that will bring it closer to damp earth underground."

I have a friend in the city of Queretaro that lost all their appliances (and computer equipment) through a heavy surge. That sure turned out to be pretty expensive for her, not to mention all the food that was wasted from the fridge.

This is precisely my point for ensuring the best grounding I can set.

robt65

YucaLandia

May 10, 2011, 6:45 AM

Post #17 of 29 (4511 views)

Shortcut

Re: [robt65] USA - Mexico Voltage Differences for Wire Size

Can't Post | Private Reply

In Reply To

Hi Steve,
Thanks for the response . . . . . . You said: ..voltage in Mexico is often not as well regulated as in Canada or the US. Typical voltages in Mexico can run from 105V AC to 138V AC. You seem concerned about having large enough gauge wires due to higher than 110V, but this seems upside down. When the voltage is higher than 110V, the current drawn for the same wattage load is proportionally higher. ..”

(This last (Bold / Italic) section or your remark is exactly my argument for a decent size wire for those occasional (and in this part of Mexico) not too infrequent number of times of power surges that cause me to be concerned. For the slight price difference for the protection provided, I think this larger size wire makes good sense. Under the circumstances don’t you agree?

The sizes that Rolly quotes above are fine. Smaller voltage spikes/surges that occur here are accommodated well by the wire specs he offers, because typical US electrical codes include a 50% to 100% fudge factor. e.g. From the Handbook of Electronic Tables and Formulas for American Wire Gauge:
8 ga wire conservatively carries 73A in Chassis applications vs 24A in constant power transmission, and a fusing current of 472A.

These figures use the very very conservative 700 circular mils per amp. Earlier standards used a still conservative 1000 circular mils per amp standard.

This all means that the built-in safety factors in Rolly's figures covers pretty much all conditions, except lightening strikes.
===============================================

In Reply To

you have given me exactly what I have been looking for (especially regarding the 220) with one exception. I am using a wire size #6 for the juice traveling from the meter base to the house (100 ft (approximately away from the electric panel box. One of my reasoning’s, is that I would suspect (due to distance) some drop in voltage, maybe not significant, but some drop. Do you agree with that surmise? I am also concerned about the size wire between the panel breaker box and hi usage electrical equipment bought in the USA, such as the large microwave, AC's, swimming pool (future project) pump / filter system, or an outdoor Jacuzzi, clothes dryer, gas / electric dual-fuel range with an electric convection oven (commercial grade), etc., I'm thinking that I should use a # 8 wire, with the 220 breaker. Of course the amp size of the breaker would match the amp size plus 10% of the specific electrical unit I was sending power to. What’s your take on the # 8 wire size for that use?

Thanks again Steve for your help.

robt65

Here are the official specs:
8 ga wire has 0.63 ohms per 1000 ft
10 ga wire has 1.00 ohms per 1000 ft
12 ga wire has 1.59 ohms per 1000 ft
14 ga wire has 2.53 ohms per 1000 ft

These figures say that the resistance losses for your proposed 100 foot run of wire are trivial, and that Rolly's figures listed above are more than adequate and safe for your proposed applications.

You can install the heavier cable you propose if you like, but it would be serious overkill. It would be better in spend the extra money on either a good voltage stabilizer or on good lightening arrestors.
Gotta run, late to see INM,
steve
-
-
Read-on MacDuff
E-visit at http://yucalandia.com

robt65

May 10, 2011, 7:48 AM

Post #18 of 29 (4500 views)

Shortcut

Re: [YucaLandia] USA - Mexico Voltage Differences for Wire Size

Can't Post | Private Reply

Hi Steve and Rolly,

Thanks ever so much for all the tutorials. I had not even considered the infamous NOB "fudge factor". I have alreadfy ordered the voltage stabilizer, and also have ought sufficient CGFI for the kitchen and bathrooms. Thanks to you both for all the help.

I sure hope other people will read this forum posting and use it as have I as a good education.

robt65

YucaLandia

May 10, 2011, 2:25 PM

Post #19 of 29 (4474 views)

Shortcut

Re: [robt65] USA - Mexico Voltage Differences for Wire Size

Can't Post | Private Reply

There's one useful item I forgot to mention in the previous post: allowable voltage drops for various wire gauges.
For future use, here's a web link that includes a handy calculator for determining voltage drops for your proposed combination of Copper/Aluminum, length of wire, gauge of wire, and expected amperage draw, providing the actual voltage drop and Percent voltage drop. Nominal voltage drops of 4% are commonly accepted, with up to 5% voltage drops between the source and the final outlet are generally considered acceptable.
http://www.powerstream.com/Wire_Size.htm

For 10 ga wire:
This translates to an allowed 23A continuous draw at 120V on 100 ft of 10 ga copper wire => equivalent to 3 small air conditioners running continuously or

This translates to an allowed 47A continuous draw at 240V on 100 ft of 10 ga copper wire => equivalent to 7 small air conditioners running continuously or four 25,000 Btu older split air conditioners at 12A each running simultaneously * or

=========
or for 8 ga wire:
38A continuous draw of 120V on 100 ft of 8 ga copper wire => equivalent to three older 25,000 Btu air conditioners @ 12A each.*
or

75A continuous draw of 240V on 100 ft of 8 ga copper wire => equivalent to six older 25,000 Btu air conditioners @ 12A each.*

Do you expect to run six large 25,000 Btu air conditioners simultaneously? If so, then you would need the 8 ga wire for your 100 ft. run.

http://www.powerstream.com/Wire_Size.htm
steve
-
*I chose specs for older more inefficient air conditioners, in case your home has 20 year old units.
-
Read-on MacDuff
E-visit at http://yucalandia.com

(This post was edited by YucaLandia on May 10, 2011, 3:31 PM)

robt65

May 11, 2011, 7:31 PM

Post #20 of 29 (4419 views)

Shortcut

Re: [robt65] USA - Mexico Voltage Differences for Wire Size

Can't Post | Private Reply

I want to thank all of you with replies. I have learned a lot here the past few days and have certainly learned some things I should have thought about and did not. I have also learned to change some of my thinking about wire sizes after the various responses. I am use to doing my architectural remodel work on strictly large higher educational facilities, Health Care Facilities and other larger governmental projects. That is a world away from residential projects . . . . . . . totally different animal. For this reason I may tend to “overkill” on sizes and safety. Thanks again for a very informative response from one and all.

Robt65

robt65

May 16, 2011, 5:04 AM

Post #21 of 29 (4381 views)

Shortcut

Re: [YucaLandia] USA - Mexico Voltage Differences for Wire Size

Can't Post | Private Reply

Hi Steve,

Thanks for this particular posting you made to this original post. It really gave me some additional perspective to think about concerning wire size. You cited:

For 10 ga wire:
This translates to an allowed 23A continuous draw at 120V on 100 ft of 10 ga copper wire => equivalent to 3 small air conditioners running continuously or

This translates to an allowed 47A continuous draw at 240V on 100 ft of 10 ga copper wire => equivalent to 7 small air conditioners running continuously or four 25,000 Btu older split air conditioners at 12A each running simultaneously * or

=========
or for 8 ga wire:
38A continuous draw of 120V on 100 ft of 8 ga copper wire => equivalent to three older 25,000 Btu air conditioners @ 12A each.*
or

75A continuous draw of 240V on 100 ft of 8 ga copper wire => equivalent to six older 25,000 Btu air conditioners @ 12A each.*

Do you expect to run six large 25,000 Btu air conditioners simultaneously? If so, then you would need the 8 ga wire for your 100 ft. run.

http://www.powerstream.com/Wire_Size.htm

Since I already have on hand some 2000 ft of 2/12 Romex on hand and 750 foot of underground #6 wire on hand, I think I will just use some # 8 (I also have on hand) for the connections from the panel box to the various 220 draw electrical equipment I have. I am only using the # 6 for the connection from the meter box to the panel which is at 114 foot away from the meter. I got all my “on hand” wire at about a “less than 50% cost” from a friend while in the USA, which was left over from a very large new construction hospital project. I couldn’t even begin to justify selling that and getting a smaller size wire, it just wouldn’t make sense.

Robt65

at7mbe

Aug 23, 2011, 6:33 PM

Post #22 of 29 (3789 views)

Shortcut

Re: [YucaLandia] USA - Mexico Voltage Differences for Wire Size

Can't Post | Private Reply

I found this thread when searching for information on whole house surge protectors for my home in Pátzcuaro.
Sorry to revive an old thread, but there's a typo in one reply that then lead to a misunderstanding further down in the thread. Rather than have others make that mistake, I thought it best to correct it here.

YucaLandia said (emphasis added):

Quote

When the voltage is higher than 110V, the current drawn for the same wattage load is proportionally higher. e.g. A microwave oven rated at 1500W draws roughly 15% lower amperage at 127V (17 amps) versus 19 amps at 110V.

The word higher is an obvious typo - for a constant load, as the voltage increases, the current draw is proportionally lower, as the example correctly illustrates. Amps = Watts / Volts.

Unfortunately robt65 followed the word and not the example when he wrote:

Quote

(This last (Bold / Italic) section or your remark is exactly my argument for a decent size wire for those occasional (and in this part of Mexico) not too infrequent number of times of power surges that cause me to be concerned. For the slight price difference for the protection provided, I think this larger size wire makes good sense. Under the circumstances don’t you agree?

It certainly won't cause any electrical problem to use larger-than-needed wire, provided you can pull it through the conduit. But doing it solely as a precaution against higher-than-normal voltage isn't necessary. The heating effects on a wire are current squared times the wire's resistance. Higher voltage means lower current for a constant load, and less heating. That's why long distance transmission lines are run at the highest possible voltage -- 300 KV or more, to get the current and heating effects down as low as possible.

Two caveats:
1. with a pure resistive load, like an incandescent bulb, the power increases with higher voltage, and the current does increase as well.
2. if you're plagued by low voltage, the current will increase for a constant load as the voltage falls.

I'm still undecided about what to buy for whole house protection in case anyone has any specific equipment recommendations. I'm thinking a Square D SDSB1175 Whole House Surge Protector and a Boost/Buck Transformer wired for a 6% buck to get my home's 128 VAC down to 120.

Thanks.

DavidHF

Aug 23, 2011, 6:50 PM

Post #23 of 29 (3785 views)

Shortcut

Re: [at7mbe] USA - Mexico Voltage Differences for Wire Size

Can't Post | Private Reply

Your caveat #1 defies Ohms law.

at7mbe

Aug 23, 2011, 8:53 PM

Post #24 of 29 (3767 views)

Shortcut

Re: [DavidHF] USA - Mexico Voltage Differences for Wire Size

Can't Post | Private Reply

I don't think so. I = V/R. R is constant, so I is proportional to V. Increase the voltage with a constant resistive load and the current will increase proportionally. At least that's the Ohm's law I learned when getting my E.E. degrees.

DavidHF

Aug 24, 2011, 8:57 AM

Post #25 of 29 (3728 views)

Shortcut

Re: [at7mbe] USA - Mexico Voltage Differences for Wire Size

Can't Post | Private Reply

In #2 above you say as voltage falls, current will increase. Now, which is it? It can be that current increases regardless of the direction of change in voltage.

1 2 View All