May 10, 2011, 6:45 AM
Post #17 of 29
Re: [robt65] USA - Mexico Voltage Differences for Wire Size
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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.
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? Here are the official specs:
Thanks again Steve for your help.
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,
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