HP ESA-E Series Programmer's Manual page 290

This is a Safety Class 1 Product (provided with a protective
WARNING
earthing ground incorporated in the power cord). The mains
plug shall only be inserted in a socket outlet provided with a
protected earth contact. Any interruption of the protective
conductor inside or outside of the product is likely to make the
product dangerous. Intentional interruption is prohibited.
If this product is not used as specified, the protection provided
WARNING
by the equipment could be impaired. This product must be used
in a normal condition (in which all means for protection are
intact) only.
The instruction documentation symbol. The product is
marked with this symbol when it is necessary for the
user to refer to the instructions in the documentation.
This symbol is used to mark the on position of the
power line switch.
This symbol is used to mark the standby position of the
power line switch.
This symbol indicates that the input power required is
AC.
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