Looks like it has become a standard, but I have actually no clue. I prefer to work with old phones; max 48V DC + 90V 25HZ
dsk
Its ok. I want to say thank you over and over, at this point you have given me mountains of information!
I am still learning all of it!
So, considering the transformers, am I correct 3 types of IT supplies existed in Norway?
230 IT
400 IT
690 IT
And 400 and 690 in buildings was stepped down to 230 with building owned transformers?
Here is the USA larger buildings are fed with 277/480Y TN-C-S supply from power provider. 277 for lighting and 480 for motor. 480 is then stepped down to 120/208Y TN-S in the building for electrical sockets.