Should I install NEMA 14-30 or 14-50?

[jcanoe]

Well, technically it can add a 50A as long as I don't simultaneously use other appliances, which won't be a problem for me

A load calculation would probably show that you don't have capacity for adding a 50A circuit. One option is to wire for a 50A circuit now and install a 30A breaker and 14-30 receptacle. Later if you decide to upgrade your service and panel, you can re-use the wire with an upgrade to the breaker to 50A and the receptacle (change to 14-50) at minimal additional cost at that time. The cost for 6 gauge wire versus 10 gauge wire is not that much additional money. The electrician will spend the same amount of time pulling, installing 6 gauge versus 10 gauge wiring.

 

[EVer Hopeful]

The electrician will spend the same amount of time pulling, installing 6 gauge versus 10 gauge wiring.

...unless he has to round a couple of tight corners