The electrician I have coming to finally upgrade my service entrance and main panel is unavailable for a couple of days, and I need to go get some wire (tomorrow) before I can talk with him again. He does not take credit cards and I only have enough cash for his labor and miscellaneous parts, and that is why I am the one buying the wire ...
... and I forgot to ask him specifically what he needs for the run to my wife's washer/dryer combo unit.
The unit needs 240V (30A), but I do not know whether to get 10-2 w/G, 10-3 or 10-3 w/G. I will be getting some regular 10-2 w/G for a water heater to be installed later on, but the washer/dryer combo has 120V stuff internally and that makes me think I should have either 10-3 and then run an equipment ground to a pipe or else use 10-3 w/G so there is a regular "shared neutral" for the 120V aspects of the combo unit either way. So, which should I buy tomorrow:
10-2 w/G, 10-3 or 10-3 w/G?
The unit is presently running on 12-3 (a pre-existing dryer line based on an ancient code allowing 30A on 12ga wire, I assume, and we never run the washer and dryer at the same time (and the dryer only draws 20A)), and then the unit also has a separate ground wire running from chassis to a nearby copper pipe, but I will get 10-3 w/G if that is what the inspector will be expecting to see.