Martin, Sure! The National Electrical Code (NEC) requires that the equipment grounding conductor (green or bare wire) must always follow the same route and wireway used by the supply and return conductors. There must never be any deviation from this basic requirement. The three wires (hot, neutral, and ground) feeding every receptacle must always run together, but the R56 manual proposes that the grounding conductors of some "technical" receptacles shall follow a path separate from the hot and neutral conductors. That is not allowed by the NEC, since that would greatly increase the impedance of the grounding system and thereby reduce the protection of the circuit against faults. Also, the NEC requires that the system grounding conductors, equipment grounding conductors, and lightning protection grounding conductors must ultimately be bonded together to create ONE grounding system. The R56 manual proposes a scheme that creates separate grounding circuits that can create dangerous voltages on some circuits if a fault occurs on another circuit. Despite some really creative schemes to create separate grounding paths, such schemes are not allowed by the NEC or by state electrical codes based upon the NEC.
Readers following this thread should be aware that the NEC is updated every three years, and becomes law as each state or commonwealth ratifies it through legislative action. The current edition of the National Electrical Code, NFPA 70, is the 2008 edition. 73, Eric Lemmon WB6FLY -----Original Message----- From: [email protected] [mailto:[email protected]] On Behalf Of rahwayflynn Sent: Wednesday, April 08, 2009 6:39 PM To: [email protected] Subject: [Repeater-Builder] Re: Motorola R56 grounding --- In [email protected] <mailto:Repeater-Builder%40yahoogroups.com> , "Eric Lemmon" <wb6...@...> wrote: > However, there are a few recommendations for equipment > grounding that violate the National Electrical Code, and would be > nixed by a competent electrical inspector. Eric, I have NFPA 70 and the R56 document: Do you have examples of the the above? I would like to do an "eyeball compare". With that in mind, a precedence statement needs to go into the tower lease agreement I have in the library. Martin
