I do like that site but I'm not very excited to see instructions on how to make a 240v plug to 120v socket instructions
True it is mentioned to label the adapter "only for EV charging" but IMO it's too easy for an adapter like that to fall into the wrong hands with catastrophic results. IMO a better alternative(and what I've done) is to install a 240v plug on your dual voltage EVSE and then when plugging into 120v, use a 120v male to 240v female plug converter. That way if the adapter falls into the wrong hands, the worst thing that would happen is someone would give a 240v device 120v, much better than giving a 120v device 240v
I also agree with cwerdna, pre '13 Leafs and '13 and on S Leafs(without charger package) pull a max of 16a @ 208/240v, pre '13 Leafs also only pull a max of 12a @ 120v, not sure about max 120v on '13 and on S Leafs as I don't have one......
I'm also not to excited about the advisement to use 14 gauge for said outlet adapters, in the case of a post '12 6.6kw Leafs, they have the potential for 27.5a @ 120v, something that would surely fry 14 gauge wire
I use 10 gauge wire on all my outlet adapters, 10 gauge is rated for 30a and is safe for all cases with a Leaf.
Again nice site, I personally have built and on occasion use a somewhat unsafe(not using relays) Quick220v device, I do know to unplug the EVSE first to avoid the potential for 120v back feeding through the EVSE to a 120v male plug but as you noted, such a device with relays is really the way to go, especially if there is the chance of such a device falling into the wrong hands. Also not mentioned is the potential(on non-dedicated outlets or circuits where more than one outlet is fed from the breaker) is if just one of the 120v circuits trips a breaker, you have the potential for your EVSE back feeding power to the tripped circuit. Essentially what this does is to put your EVSE in series with all the devices on the tripped circuit, again something that's not a good for either your EVSE or other devices.