Inside voltage does not match meter

Just had a question come up on a recent inspection, in Mexico. The meter shows that it is a 120V (100)A 2F 3H 2E. The question is how are they running 230v air conditioners? In the vault in front of the house there are two black and one red going to the meter. Is this hot, neutral and ground or two hots with a neutral? Could not find a voltage converter in the house.

Any photos?

What does the bold part mean?

It is describing the service. 2 phase 3 wires

240v is single phase. Sometimes referred to as “split phase.” 240 volts is derived from a transformer with a SINGLE secondary winding and with a center tap.



It looks like they are only using one leg to obtain the reading.

It is not likely to be two-phase. You can verify it with an oscilloscope. In two-phase, the phases are 90° apart. Three-phase are 120° apart. The legs on single-phase are 180° apart.

William, Hi…! Pedro here…
We need more information on, What is that that you are looking at? and What is your specific concern?

Air conditioners condensers usually run on 2 phase circuits, 240 Volts (220 to 240 range is Okay). Yeah! Those are two phases coming from the Main panel and naturally the dwelling is been served with two phases from the public drop (Acometida Bifásica de 240 Voltios en Mexican). There are ‘some’ window units (small demand) under 9.000 BTU that may run on 120Volts One phase, but those eat a lot of power (current = amperage). Higher voltage (240V) imply lower current drawn and more efficient. To determine What you have there, You need a Multimeter and measure voltage from phase-to-phase (black to black) looking for 240 Volts. Any phase (black to the other wire) must read 120 Volts. The label in the meter is another story.

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240 volts is single phase as I posted earlier. Sometimes called split phase. It tells you right on the Carrier label he posted.


120 volts or 240 volts both are single phase. With the exception of a little more voltage drop on a 120 volt circuit there is practically no difference in efficiency between 120 volt and 240 volt units.

And the label in the meter is the problem. The buyers are stuck looking at the meter and saying they are not getting 240v to the house. I did verify from black to black that there is 232v. The buyer is just stuck on the meter saying if the meter says 120 then there can not be 240 in the house. Even after I show there is 232 at the panel…??? I am trying to justify the meter to them.

Let them convince the agent or the power company! You’ve done all you can do.

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No, they don’t.

DO NOT use a mains powered oscilloscope. Bare minimum you will burn up your probes, more likely you will fry the unit.

Anyone who owns an oscilloscope probably knows how to use it and knows to use the proper probs.