pianotuna wrote:
Nec may forbid "hard wired" installation of devices, but since my autoformer unit is a plug in device it is not forbidden and is perfectly legal. There are many thousands of these in use in Mexico.
Mexico is not US. Besides, you can google some manufacturers who jumped into this bandwagon only to discontinue this product or went belly up because they cannot fool all the people. No one will stop you from using it or simply using it as foot rest which could be more useful than expect it to boost power.
There is no doubt this can be useful in Mexico because some rural areas there are feed by 240Vac. Having a center tap will enable you to use 120Vac appliances sold for US consumer.
I refuse to open the link you provided because I don't want to be suckered just like the rest.