On Thursday, 7 December 2017 21:17:18 UTC, Michael Terrell wrote:
tabbypurr wrote:
On Tuesday, 28 November 2017 23:08:59 UTC, whit3rd wrote:
On Tuesday, November 28, 2017 at 12:48:01 AM UTC-8, GS wrote:

Commercial isolation transformers get rid of common mode noise, and
since one leg of output is tied to ground, forms a new local
neutral.

That's only true of SOME isolation transformers; the ones used for
bench safety when working on live equipment do NOT make the
neutral-ground connection.

Quite. And building site transformers earth the centre tap.


IOW, they convert the European 240volt system to the American
120V/240V system.

They output 110v centre earthed, so nothing is over 55v ac from ground. It was the building site standard until RCDs made 110v not really needed.


NT