24-10349-8 Rev. B C-1
Appendix
C
This document contains confidential and proprietary information of Johnson Controls, Inc.ï€
© 2012 Johnson Controls, Inc.
GROUNDING AND CONNECTORS A
This appendix gives instructions for grounding cable shields at data and low voltage
installations, and at grounding card reader units. Follow these guidelines for electromagnetic
compatibility (EMC) conformity, and to improve system reliability. In some cases, European
requirements (EN standards) differ from the USA requirements (FCC standards). Refer to
the relevant sections for these requirements.
Every unit in a Johnson Control’s installation must have its chassis bonded to a verified
electrical ground (earth). In all cases, the local wiring codes apply.
The National Electrical Code NFPA 70 must be followed for installations in the USA.
The Canadian Electric Code, C22.1 must be followed for installations in Canada.
BSI Standard BS7671 (latest edition) must be followed for installations in Great Britain.
Additional information is given in the Cardkey Installers’ Code of Practice.
IMPORTANT
Conduit ground, cold water pipes, unbrazed joints, or dissimilar metals are
unacceptable in the path of either building or supplement ground. Where
grounding is required, connect only to the proven building electrical system
ground (earth).
CABLE GROUNDING
All data and low voltage cabling must be shielded (as specified by the relevant manual).
Connecting shields to chassis ground differs, depending on the nature of the installation.
The following subparagraphs describe recommended grounding requirements in the USA
and in Europe. Note that in the illustrations accompanying the descriptions:
 The outer cover of the cable has been stripped back to reveal the cable’s shield.
 The shield is cut back so it just enters the enclosure.
 The drain wire that extends from the shield shown in the illustrations must be kept as
short as possible (typically, 2.5 cm or 1 inch). Connect a lug to the end of the wire,
as shown, and screw securely to the wall of the enclosure or nearest stud.
 All internal ground (earth) bonding straps must be left intact after installation.
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