Mains Isolation Transformer

[Ian.M]

A power tool site transformer is a lot cheaper and there are usually plenty of second hand units to be had.

and will only kick out half the voltage you chuck in

Since the O.P. is in the USA, that isn't really an issue.   A 55-0-55 Reduced low voltage site supply transformer's total output voltage is near enough the same as one side of their nominal 120-0-120 domestic supply, and if they can't find one with 120V input, they can run an imported 230V input one from a 240V circuit.  However, its seldom worth importing used transformers as the high weight makes shipping prohibitively expensive.

Also, as noted by Terry, the center tap of the 55-0-55 is grounded, to meet applicable regulations for site supplies, and as site transformers are commonly potted, you cant really tell if it can be converted to a (floating) isolation transformer  until you have it on your bench with the lid off.

[madires]

Or look for a used medical isolation transformer and remove the earth/ground connection of the secondary winding.

[themadhippy]

Since the O.P. is in the USA, that isn't really an issue

How is it not an issue? the  original post  was about a 1:1 isolation transformer,suggesting a 2:1 site transformer isnt going to work. you might as well suggest a shaver socket ,  it will provide the correct 1:1 isolation after all ,but wont be much use if you need more than a few mA

[Ian.M]

It isn't an issue because homes in the USA typically use a 120-0-120  split phase mains supply, and although the commonest outlets are NEMA 5-15R and NEMA5-20R providing 120V to most devices, anyone serious about electronics or DIY will have a 240V split phase (3 wire + ground) circuit to their workshop and at least one 240V outlet they could supply a site transformer from, then run 120V devices from the site transformer.

[bdunham7]

This might be a handy option, especially if you need to step the voltage up or down at times.  You'd need IEC C13 extension or adapter cords, but those are readily available.

https://www.ebay.com/itm/134092407056

[james_s]

Since the O.P. is in the USA, that isn't really an issue.   A 55-0-55 Reduced low voltage site supply transformer's total output voltage is near enough the same as one side of their nominal 120-0-120 domestic supply, and if they can't find one with 120V input, they can run an imported 230V input one from a 240V circuit.  However, its seldom worth importing used transformers as the high weight makes shipping prohibitively expensive.

Also, as noted by Terry, the center tap of the 55-0-55 is grounded, to meet applicable regulations for site supplies, and as site transformers are commonly potted, you cant really tell if it can be converted to a (floating) isolation transformer  until you have it on your bench with the lid off.

Site transformers aren't a thing here, so it would have to be imported and that's going to cost a lot more than buying a proper benchtop isolation transformer even if you get it for free and just pay the shipping. Power tools here run on 120V directly out of the wall, building sites use GFCI protection with no isolation.

[Ian.M]

I suspected that was the case.

[Terry Bites]

You can get 110 to 55-0-55 site transformers- though not in the uk.