My introduction to the electrical field, was at a Naval Technical Training Center. The school I attended was "Aircraft Electrician, Class A". I was taught that the term "bonding" was to provide an electrical connection between two conductive objects, to insure a viable low resistance current path. This was often a necessary procedure on aircraft, for both the DC and AC systems. It was not only for carrying fault current it was for completing a circuit, in many cases. I personally feel that calling the conductor to a water pipe, gas pipe, or any other conductive object, that requires grounding, does not fit the definition of a bonding conductor. I think it should be called a piping system ground wire, and nothing else. Bonding conductors do not always connect to the neutral buss. A ground conductor does. I think this adds confusion to the proper terminology, in reference to the purpose. I know the common acceptable term is "bond" when referring to the conductor for only fault current purposes. I do not agree. I am interested in other opinions, and the technological explanations for this determination.
Bennie, I too think there is a problem with the "bonding" and "grounding" terms, however mine opinion is almost opposite of yours. I thing that the only time the word "grounding" should be used is for the conductor that connects to the grounding electrode. All of the other conductors that we call "grounding" are in fact "bonding" conductors. The current use of the terms often leads installers to try to connect things to "ground" when they should be bonded back to the electrical system. We are not trying to "ground" the water pipe or the other conductive objects, but we are trying to "bond" them so that if they would become energized by some accidental contact with a hot conductor, there would be a low impedance path back to the system to clear the fault. A connection to ground is not required to clear faults on building systems, but a bonding connection back to the system is. We both should submitt proposals on this subject for the 2005 code. Don(resqcapt19)
This is very good Don. I agree we are going the same direction, maybe different paths I once posted the question; can a neutral, equipment ground, bond, and ground electrode conductor serve other purposes?. I received all answers as definitely, no! A neutral can carry load current, and fault current. A ground electrode conductor can carry load, fault, and transient current. An equipment ground conductor will only see fault current. A pipe bond will only see fault current. The original explanation that was taught to me in technical school, is this entire list of terms is a grounding system. All are electrically connected, therefore one system. Not a combination of systems, due to them having different performance requirements. This grounding system is also an extension of the primary supply to the distribution transformer. The No. #14 ground wire in my light circuit, has a direct electrical/mechanical connection to every home, in my area, that is supplied from the same sub-station. My understanding of fundamental circuitry is that any conductor, regardless of its function, that is directly connected, is one system. Most wireman have no problem with understanding the active line conductors on individual branch circuits. There appears to be some confusion in the understanding of the low side grounding system, including the neutral. By performing different functions, and applying different names, I feel this has falsely implied that each conductor is a separate system. I think this has developed, over time, by mis-applying proper terms, and the function being corrupted. I was reminded of my original studies, and the fundamental application of theory, when I reviewed the European concept that is called the Multi-Earth Neutral (MEN) system, for grounding. We use the same concept, only it is explained in a manner that has created a lot of unnecessary confusion.
Very interesting thread here. You two have seen the history concerning this subject evolve, and both have reservations as to it's present state. Myself, i think the terminology clouds the intent. There seems to be agreement on installation, and squabble over what to call it. In recent history Art 250 was overhauled, as i'm sure you're well aware. One article i had read previous to this had mentioned how it was to become user friendly. Perhaps just addressing basic terms as this thread would have been a better outcome.
I think that what I see as a problem is the emphasis on the word "grounding". Grounding does not provide safety in our systems. Grounding will not clear faults. However the over use of this word in the code leads many to believe that we must connect everything to earth to have a safe system. If everything is connected to earth, but there is no connection to a system conductor we have a very unsafe system. I would like to see the word grounding replaced everywhere in the code with the word bonding unless we are talking about a direct earth connection as in the grounding electrode system. Don(resqcapt19)
Re: Definitions?#76892 03/29/0107:10 AM03/29/0107:10 AM
We say the conductor to the earthing electrode or your point of earthing is the "earth or earthing conductor" any others i.e. conductors from earth buss to copper pipes, stainless sink tops, Metal meter box are "bonding conductors"
Re: Definitions?#76893 03/29/0109:13 AM03/29/0109:13 AM
I am completely in agreement to the term "bond" being used for connecting metal parts together, other than the connection to the neutral/ground buss. The reason is that it can be both an electrode, and bond conductor, in some cases. The term "bond" has always been used for describing the jumpers around loose, or no connection, of metal components, not necessarily the grounding of the parts. This is common in the electronic, telecom, automotive, aircraft, and marine applications. I prefer the term "ground", for its implication that the object is at ground potential. I like to apply the following as components of the grounding system; Neutral/ground, equipment ground, and earth ground. All are components of one electrical system of grounding. The descriptive word with the term "ground", indicates its function.