208 to 240

| Anyone ever swapped a 208 main for a 240 going to a residence. There | is a manhole cover one house down with both mains running alongside. | It's doable, but was wondering about cost, (especially from the utility | for switching), general experience, etc.

Let's see if I understand correctly. 208Y/120 goes by the house. The utility would get you 2-legged 208/120, but that means your 240 volt stuff is underpowered. You want to know what is involved in turning that into genuine 240 volts?

I'd say you are better off just taking the 208 as is. Let that run all the 120 volt loads as is. Then take off a 2-pole circuit and feed that through a 208-to-240 single phase dry transformer. From there, it goes to a smaller subpanel just for the loads that need genuine 240 volts. This keeps the transformer smaller.

Loads that do NOT use a neutral could be boosted to 240 volts with an even smaller buck boost transformer. The line-to-ground voltages will be higher than 120 volts, but not by a great deal. But loads that DO need a neutral need a full isolation transformer to get them right, or would have to be doubling a single 120 volt phase to 240.

You need to know why you got stuck with 120/208 in the first place.

Was it easier for the utility to tap off an existing transformer serving some nearby business, apartment or condo? Do you have your own (exclusive) distribution transformer?

You didn't say where you lived, but in the USA, the standard service for single, stand alone residential dwellings is 120/240V. There must be some pecular reason why you got stuck with 208V.

In general, if it involves the utility swapping or installing a new transformer, they probably won't do it, unless you pay.

Beachcomber