Compuprint 4247-Z03 - Manual (Page 192)

Safety
Safety is a major consideration in the design and manufacture of this product.
Proper electrical grounding is essential for safety and for reliable operation of the
printer. If you have any questions about the grounding of your receptacle, ask your
electrician.
Branch circuits and grounding
A machine must be properly grounded. It is recommended that an insulated
green-wire ground, the same size as the phase wire, be installed between the
branch circuit panel and the receptacle.
For personal safety, the ground should have sufficiently low impedance to limit the
voltage to ground and to facilitate the operation of circuit protective devices in the
circuit. For example, the ground path must not exceed 1 ohm for 120-volt,
20-ampere branch circuit devices.
DANGER
<1-30> The construction of this printer provides extra protection against
the risk of electrical shock by grounding appropriate metal parts. The extra
protection may not function unless the power cord is connected to a
properly-grounded outlet. This printer has a grounding-type (3-wire)
power cord because grounding is necessary. It is the responsibility of the
customer to the person installing the printer to connect it to a
properly-grounded outlet. Seek professional assistance before using an
adapter or extension cord; such a device could interrupt the grounding
circuit.If this printer is connected to an outlet that has been incorrectly
connected to the building wiring, serious electric shock could result.
176 User's Guide