Electrical – Confusion over 220 and 230 volt outlets

240velectricalvoltage

We have a 220 outlet for our A/C. We are shopping for a new unit and all I am see is 230 volts on the units. Will we have to rewire with a new outlet for a new A/C?

Best Answer

Two issues:

  1. In the world of electrical power devices, there is a "Distribution Voltage" that your utility is providing to you, and there is a "Utilization Voltage" that your devices are designed to work on. They are not the same values, because it is EXPECTED that there will be a "voltage drop" that takes place between the utility transformer and the point at which the device connects due to the resistance of the wire between them. Distribution voltages are required to be +-5% maximum deviation, Utilization Voltages are supposed to be +-10% minimum acceptable.
  2. Distribution voltage levels have changed over the years. Here in the US (we don't know where you are), 220V was an old original standard going back to the 1920s. Some time around the 1930s, as part of one of Roosevelt's "New Deal" programs called the "REA" (Rural Electrification Act), power lines were run out to farms and small communities all across the country. So to avoid having the REA workers have to carry different products for different utility voltages, a standard was established that has become codified as the ANSI (American National Standards Institute) Distribution Voltages that power utilities are SUPPOSED to adhere to. So for residential single phase distribution, the official voltage is actually 240VAC. But because old habits die hard, and because SOME utilities never actually changed, "220V" is a common term still used all over the place. It's actually somewhat rare for it to actually BE 220V. Generically, it's all referred to as being the "nominal" voltage; 220, 230, 240 all being relatively close enough.

So partially because of this, the unofficial "Utilization Voltage" level has been 230V for decades, but the tolerance is +-10%, meaning the devices are supposed to be designed to accept anything from 207V to 253V. In reality because some commercial and apartment complexes will use 208V 3 phase distribution, and you want to be able to accept 90% of 208V, the equipment manufacturers often actually make their products suitable for -15% from 230V (195V).

RARELY, something is either old, or made somewhere where they don't follow industry norms (or don't understand, or don't care) and they made it so that it STRICTLY requires a very narrow input voltage. So bottom line you should check. But if it is something like a dryer or an oven outlet, it should be perfectly fine.

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