High Voltage Safety
High Voltage batteries can be very dangerous to work with, so this is a non exhaustive document of safer working processes, always be sure you're competent and aware of the risks and how to mitigate them. Anything you undertake, you do so at your own risk. Batteries are Direct Current (DC) so this wiki page will concentrate on DC as opposed to Alternating Current (AC) as typically found in household outlets.
What is considered high voltage?
The Occupational Safety and Health Administration (OSHA) warns that voltages over 50V pose a shock hazard and for DC, 60V is often cited as the voltage where electrocution becomes possible under worst-case conditions.
https://electricalengineeringx.com/what-is-the-safe-limit-of-dc-voltage-for-humans-to-touch/
OEM high voltage batteries are currently typically around 350-400V though some are moving up to higher voltages of 800V. Very few DIY conversions are currently using voltages as high as 800V for the most part, so this page will concentrate on the ~400V range. As the voltages increase the conductivity of materials increases so, make sure you're aware of the risks and safe working practices.