thank you Don, very informative information below. and also, for the EU, in terms of signal cable, for ethernet or interface cables (E1/T1) will need to meet the 61000-suite of tests most notibly surge and conducted disturnances as its intended to be 100 meters or more. good luck Pierre, regards Richard,
From: [email protected] mailto:[email protected]]On Behalf Of Don Gies Sent: Monday, March 14, 2005 10:38 AM To: Pierre Selva; 'Forum Safety-emc' Subject: RE: Grounding, Earthing of long cables Pierre, For North America, you will need to consider the applicability of the following, particularly the long (signal) cable that may go from inside to outside plant: 1. (US) - National Electrical Code - NFPA 70 - Article 800 - Communications Circuits a. Flammability of cable - after 3 meters, you must meet the appropriate flammability rating of the cable. Your signal cable is considered a "wick" for spreading flame, and may be part of a "multi-wick flame-spreading system" if it is bundled. There is a flammability hierarchy, starting with suffix X, as in type CMX, for limited-use cable (does not apply to you), going to CM or CMG (general use, not going up verticle shaft to other floors), then CMR (for "riser cable") then finally CMP (for "plenum cable" or cable suitable for use in ducts, plenums, and other space used for environmental air handling. b. Primary Protector - If your cable is run from building to building, and its length of 100 meters implies that it is a candidate for this, it will need to be fitted with a Listed primary protector (essentially a voltage surge protector) as close to practicable to the building entrance. 2. (Canada) Canadian Electrical Code, Part I, CSA C22.1 - Section 60 - Electrical Communications Systems Everything that is mentioned above for the US goes for Canada, as well. These sections are not written in the same text, but the requirements are very much harmonized. 3. (US/Canada) - UL 60950-1/CSA C22.2 No. 60950-1 -03 - a. Clause 6.4 - Protection Against Overvoltage from Power Cross - Since your cable is running to outside plant, you have to consider whether it is long enough that it may become exposed to power cross, or contact with overhead AC mains supply conductors. Your earthed shield on your cable will not be sufficient to protect you against this phenomena. There are relaxations for campus environment runs. b. Listed Cable - for the US and Canada, the cable you select will need to be Listed(US)/Certified (Canada) for the types mentioned above. They cannot be only Recognized Appliance Wiring Material (AWM) for the lengths you are considering. As far as earthing your cable, yes, it should be done, but you will probably find limited, if any, mandatory requirements on doing so. Hope this helps, Don Gies, N.C.E Senior Product Compliance Engineer Lucent Technologies - Bell Labs Holmdel, NJ 07733 USA From: [email protected] mailto:[email protected]]On Behalf Of Pierre Selva Sent: Monday, March 14, 2005 8:40 AM To: 'Forum Safety-emc' Subject: Grounding, Earthing of long cables Hello all, The grounding/earthing of long distance cables (more than 100m) concern the EMC and Safety matters. I'm looking for some documentation / information on how to perform a good connection to earth of this kind of cables. Mainly, I would like to know what are the normative and regulatory documents which apply in the North America and in Europe. My main interest is to identify the difference (if exist) between official rules and use and to know exactly what I have to do on communication lines (like RS485, LAN ...) or other long lines when they go outside the building. I know that in UK the BS7671 applies. What are the other applicable standard in Europe and in the US/Canada ? Do you know where I can find interesting documentation on this subject ? (except on this forum, of course !) Many thanks in advance, Best regards, Pierre Pierre SELVA Product certification manager EMITECH Rhône Alpes 1 rue des Essarts 38610 GIERES - France Ph : +33 (0)4 38 370 007 Fx : +33 (0)4 38 371 004 GSM : +33(0)6 76 63 02 58 [email protected] <http://www.emitech.fr> www.emitech.fr ---------------------------------------------------------------- This message is from the IEEE Product Safety Engineering Society emc-pstc discussion list. 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