15
W
WA
AR
RN
NIIN
NG
G
For protection against indirect contacts (depending on the type of
supply provided for and connection of earths to the equipotential
protection circuit) refer to point 6.3.3 of EN 60204-1 (IEC 60204-1)
with the use of protection devices that ensure automatic cut-off of
the supply in case of isolation fault in the TN or TT systems or, for
IT systems, the use of isolation controllers or differential current
protection devices to activate automatic power disconnection (an
isolation controller must be provided for indicating a possible first
earth fault of a live part, unless a protection device is supplied for
switching off the power in case of a such a fault. This device must
activate an acoustic and/or visual signal which must continue for
the entire duration of the fault). For example: in a TT system, a
differential switch with cut-in current (e.g. 30 mA) coordinated with
the earthing system of the building where the machine is located
must be installed ahead of the supply.