a simple correction. +\- does not denotes only polarity. yup we can consider AC source has no polarity when it comes inside our home but in industrial application it has sign convention of +\-. if you have Power Quality Analyzer you can say that AC has also polarity.correction lang ha.
Ang source of electricity natin sa mga bahay ay walang + and -
Mali nga ang sign na "danger high voltage" e. Dapat "danger high current"
You did not understand the sign "Danger High Voltage" yup current will kill us but the factor that let current to kill us is the voltage.
I will give you an example:
kung nasa gitna ka ng 2 wire carrying 10,000 ampere you only feel the magnetic current because of electromagnetic reaction. PERO kung in between ka naman ng 10,000 volts sigurado dedo ka because of magnetic arching parang kidlat kulay blue...di mo ba napansin ang mga linya ng Meralco sa poste na magkalayo dahil iniiwasan dyan ang arching. I hope you understand now...