If the coax enters the building from outside, it needs lightning protection near that point. The common method is with male F connectors on the entering and the internal cables which connect to a female to female adapter mounted on a metal bracket. The metal bracket is connected to ground via a minimum 14 AWG conductor. This grounds the shield. If it is necessary to isolate the shield, there are acceptable listed (NRTL approved) primary protectors available to serve the same purpose. Whoever is doing the installation should also refer to Article 820 of NFPA 70 National Electrical Code for other requirements on clearances, installation, cable types (flammability), where to ground, etc.
So the basic answer is for outside conductors, grounding is the easy way but there are alternatives. For cables which are contained entirely within the building, any grounding requirements are addressed by the products involved (camera and receiver). For example it may be grounded at the camera for a class I (grounded product) or floating for a class II (double insulated) product. In general, minimizing the ground connections is a good idea since stray power currents in the shield can cause artifacts in the camera image. Bob Johnson ITE Safety <http://www.itesafety.com> [email protected] wrote: Can anyone help me understand what would be the requirement, preferably worldwide worst-case if possible, for connecting the outer conductor ("shield") of the coaxial cable (RG59) in a security-camera application? The cable can be up to 2000 ft (~ 600m) long, between the central unit (inside the building) and the remote camera (anywhere within the reach). The application can be anything from industrial to apartment buildings. Can I (or do I have to) connect the outer conductor to the safety ground (enclosure) on both ends? .. on one end (which?), etc. Alternatively, do I need to provide safety isolation from the outer conductor to the safety GND (enclosure?), how much, on which end, what kind of caps to GND can I use for EMI if I need safety isolation, etc.? I am asking strictly from the safety/regulatory hard requirement point of view, not trying to discuss which would be better for EMC. Is there an simple answer? Did I miss any key info or question? Thanks, Neven - ---------------------------------------------------------------- This message is from the IEEE Product Safety Engineering Society emc-pstc discussion list. To post a message to the list, send your e-mail to <[email protected]> All emc-pstc postings are archived and searchable on the web at http://www.ieeecommunities.org/emc-pstc Graphics (in well-used formats), large files, etc. can be posted to that URL. Website: http://www.ieee-pses.org/ Instructions: http://listserv.ieee.org/request/user-guide.html List rules: http://www.ieee-pses.org/listrules.html For help, send mail to the list administrators: Scott Douglas <[email protected]> Mike Cantwell <[email protected]> For policy questions, send mail to: Jim Bacher <[email protected]> David Heald <[email protected]> - This message is from the IEEE Product Safety Engineering Society emc-pstc discussion list. To post a message to the list, send your e-mail to <[email protected]> All emc-pstc postings are archived and searchable on the web at http://www.ieeecommunities.org/emc-pstc Graphics (in well-used formats), large files, etc. can be posted to that URL. Website: http://www.ieee-pses.org/ Instructions: http://listserv.ieee.org/request/user-guide.html List rules: http://www.ieee-pses.org/listrules.html For help, send mail to the list administrators: Scott Douglas <[email protected]> Mike Cantwell <[email protected]> For policy questions, send mail to: Jim Bacher <[email protected]> David Heald <[email protected]>
