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What wire gauge should you use at home in Mexico?

Updated October 24, 2026

Wire gauge isn't chosen “just in case”. Wire that's too thin for the load heats up, and a long run loses voltage. Mexico's electrical code, NOM-001-SEDE-2012, closely follows the US NEC and also uses AWG sizes: it says how much current each gauge carries and which breaker goes with it. One difference for newcomers: household circuits here are 127 V (220 V for large appliances).

The basic table

GaugeCross-sectionCarries (60 °C)Max breaker
14 AWG2.08 mm²15 A15 A
12 AWG3.31 mm²20 A20 A
10 AWG5.26 mm²30 A30 A
8 AWG8.37 mm²40 APer table
6 AWG13.3 mm²55 APer table

Source: NOM-001-SEDE-2012, Table 310-15(b)(16), copper, no more than 3 current-carrying conductors, 30 °C ambient; maximum breakers per section 240-4(d).

At home the 60 °C column is used because the standard (110-14(c)) requires it for circuits of 100 A or less, unless outlets and breakers are rated 75 °C. And on 14, 12 and 10 gauge the breaker has a cap: 15 A, 20 A and 30 A, even if the table says the wire carries more with higher-temperature insulation.

Distance matters too

All wire loses some voltage because of its resistance. The standard recommends keeping this voltage drop under 3 % on a branch circuit. On long runs, it's the distance that forces a thicker gauge than the current alone requires.

What you connectDistanceGaugeBreaker
1,500 W at 127 V15 m14 AWG15 A
1,800 W at 127 V25 m10 AWG (distance decides)15 A
1,500 W at 127 V40 m8 AWG (distance decides)15 A
5,500 W at 220 V, over 3 hours at a time12 m8 AWG32 A

Results from this site's calculator with copper, 60 °C column, ambient up to 30 °C and 3 % maximum voltage drop.

Continuous loads

If an appliance runs 3 hours or more at full power (a heater, an air conditioner, a pump), the standard (210-19) requires the wire to carry 125 % of its current. That's why the last example, at 25 A, needs a 32 A breaker and 8 gauge.

Before you buy wire

This gives you an idea of what the standard requires. Any electrical installation must be done by a qualified electrician, who should also check grounding, conduit and real site conditions.

Enter the load and distance: we tell you the gauge and breaker.

Calculate my gauge

Frequently asked questions

What wire gauge is used for outlets at home in Mexico?

Under the NOM, a circuit with a 20 A breaker uses 12 gauge and one with a 15 A breaker, 14 gauge. On long runs, voltage drop may require a thicker gauge.

What gauge do I need for a mini-split?

It depends on its current (on the unit's nameplate, along with the maximum breaker the manufacturer recommends) and the distance to the panel. Since it usually runs for hours, it's sized at 125 % of its current.

How many amps does 12 gauge wire carry?

20 A in the 60 °C column of Table 310-15(b)(16) of NOM-001-SEDE-2012, and the standard limits its breaker to 20 A.

Can I use a bigger breaker so it doesn't trip?

No. The breaker protects the wire: if it's bigger than what the wire can carry, the wire can overheat without the breaker tripping.

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