ABB Relion REX640 User Manual page 7

Safety information
Dangerous voltages can occur on the connectors, even though the
auxiliary voltage has been disconnected.
Non-observance can result in death, personal injury or substantial
property damage.
Only trained and qualified persons are allowed to connect and operate
BIO-Tester Relion REX640.
National and local electrical safety regulations must always be
followed.
The necessary and required earthing connections must be made
according to the product guidelines and regulations.
When the withdrawable module has been detached from the case, do
not touch the inside of the case. The relay case internals may contain
high voltage potential and touching these may cause personal injury.
The protection relay contains components which are sensitive to
electrostatic discharge. Unnecessary touching of electronic
components must therefore be avoided.
Whenever changes are made in the protection relay, measures should
be taken to avoid inadvertent tripping.