In article , dennis@home
scribeth thus
On 14/04/2018 13:29, tony sayer wrote:
A nodeMCU will almost certainly do everything you want including
logging to a remote database.

Problem is dealing with mains AC voltages and having to reduce them
first.




Isolating transformers isolate the mains and reduce them to safe levels.


Care to expand of that statement Dennis?..


What's to explain? they isolate the mains unlike autotransformers or
some other ways to drop mains voltage.
You aren't going to get a sever shock from a 6V isolating transformer
like you could from a potential divider using resistors.

Isolating transformers are generally known to isolate a direct mains
connection.....
--
Tony Sayer