Table 54: Site Electrical Wiring Guidelines
(Continued)
Site Wiring
Factor
Guidelines
Radio
frequency
interference
To reduce or eliminate RFI from your site wiring, do the following:
•
Use a twisted-pair cable with a good distribution of grounding conductors.
•
If you must exceed the recommended distances, use a high-quality twisted-pair cable with
one ground conductor for each data signal, when applicable.
Electromagnet
ic
compatibility
If your site is susceptible to problems with electromagnetic compatibility (EMC), particularly
from lightning or radio transmitters, seek expert advice.
Strong sources of electromagnetic interference (EMI) can cause:
•
Destruction of the signal drivers and receivers in the device,
•
Electrical hazards as a result of power surges conducted over the lines into the equipment.
AC Power Electrical Safety Guidelines
The following electrical safety guidelines apply to AC-powered devices:
• Note the following warnings printed on the device:
“CAUTION: THIS UNIT HAS MORE THAN ONE POWER SUPPLY CORD. DISCONNECT ALL
POWER SUPPLY CORDS BEFORE SERVICING TO AVOID ELECTRIC SHOCK.”
“ATTENTION: CET APPAREIL COMPORTE PLUS D'UN CORDON D'ALIMENTATION. AFIN DE
PRÉVENIR LES CHOCS ÉLECTRIQUES, DÉBRANCHER TOUT CORDON D'ALIMENTATION AVANT
DE FAIRE LE DÉPANNAGE.”
• AC-powered devices are shipped with a three-wire electrical cord with a grounding-type plug that
fits only a grounding-type power outlet. Do not circumvent this safety feature. Equipment grounding
must comply with local and national electrical codes.
• You must provide an external certified circuit breaker (2-pole circuit breaker or 4-pole circuit breaker
based on your device) rated minimum 20 A in the building installation.
266
