My wife isn't very educated about electricity at all but when I told her on her 40th birthday that I was going to trade her in for 2 - 20's, she informed me that I wasn't wired for 220.
To me, it has always been a gray area. Today, an office person asked what we had that was 220v and I responded the dryers, HVAC, etc. The same question was asked to a peer of mine and he responded "nothing". I think that we were both right in this situation. Technically, there is not 220v, but i think I responded correctly for who/what they were asking. Someone PLEASE tell me i was right
120V: First off, the standard household voltage in North America is 120V AC, 60Hz. Most appliances are designed for this. There can be some variations in the voltage depending on the load and condition of the network. The stepdown transformer has its primary winding wired between two of the three transmission wires.
Due to growing demand of electrical heating (in dryers, ranges, water heaters and sometimes house interior heating) a system has been required that allows usage of 120V designed electronics, and is capable of providing more power for the household. For the same reason that the transfer network doesn't work with such a low voltage, the single 120V circuit can only give so much power without the power loss becoming astronomical. There are two methods used to avoid this while keeping compatibility.
240V or split phase: For small residential buildings, the usual method is to rig up a 240V stepdown transformer (instead of 120V) in which the secondary winding is split into two 120V windings (hence the name "split phase"). The center tap is then grounded and fed to the house as if it was the neutral wire of the old 120V system, and each end is wired as a separate 120V live wire. Their waveforms have a half-cycle offset, or 180 degrees, when measured against the neutral wire. The normal 120V designed machinery does not care which live wire you use for them as long as you connect them between a live and neutral wire. Appliances in the home can be distributed on either live wire to maintain balanced loading, and when heating requires high power, the concerned appliance can be connected to both live wires to operate the heating element, providing 240V for it.
208V: For larger residential buildings and blocks especially in big cities, as well as shopping malls etc, there is a system made out of two or three phases. In these cases, one or more of full three phase stepdown transformers are used to feed power to the building. These transformers have three primary windings, each wired between two of the transmission wires, in a triangular fashion. There are also three secondary windings on such a transformer. Normally these are coupled at one end, the center tap is grounded and fed into the house as the neutral wire, while their other ends are fed into the house as separate live wires. Each live wire reads 120V against the neutral point, and between any pair of live wires, you get the reading of 208V. Then, each home in the building is fed with two or three of these live wires as well as the neutral. The rest happens much like on the split phase. Appliances can be distributed on different live wires, and heating elements will be connected between two live wires.
I would tell them that you have 208VAC in the building just like you said and move on to another subject. If they ask more about that same question them address those questions to the forum. It's not good to second guest the client intentions for the use of 220 VAC.
To me, it has always been a gray area. Today, an office person asked what we had that was 220v and I responded the dryers, HVAC, etc. The same question was asked to a peer of mine and he responded "nothing". I think that we were both right in this situation. Technically, there is not 220v, but i think I responded correctly for who/what they were asking. Someone PLEASE tell me i was right
If the office person needed to know in order to order correct equipment, you were not right. Some 240 volt equipment will work OK with 208 volts, but not all.
