Grounding and Bonding Part 2

Hi, this is George with Agvo electrical services and I am the surge protector guy. So this is podcast about ground and grounding part two. So we’ll dive right back in to where we left off national electrical code article 250 dot six A affirms that grounding and bonding conductors circuit conductors, sir protection devices surge arresters and non current carrying metal parts must prevent objectionable currents objectionable current flow permanently on the grounding and bonding paths due to the improper connection of conductors and equipment. One example of incorrect circuit arrangement is having the neutral or grounded conductor connected to the ground at several points. And not only at the service equipment, what that means is the only place especially in residential, the only place where the neutral and it’s an industrial and which is not really as much most industrial doesn’t really utilize a lot of neutral wires. But in commercial wiring, we do not connect the neutrals and the grounds all over the place, the only place that we connect them is at the service entrance, the first point of disconnect entering the property the premises, all right. So objectionable current flow permanently on the grounding and bonding paths due to improper connection of conductors and equipment. One example of an incorrect circuit arrangement, okay, once again, we just said that. So this is how electricity works in magnetic skies. You know, you got a positive on or electron whatever racing around the copper conductor exactly 180 degrees away from the negative electron force, I alternating current, they’re racing around the wire, you know, around and around and around and around and around and around. And so anyway, if you don’t have an understanding of how electricity works, that’s what makes it work. You know, the drawing that I’m looking at is showing, you know, the positive force leaving the panel the heading out into the field coming across whatever device that you’re serving or whatever, and they’ve got it drawn as a load there and then the negative side is coming back to the panel or meter socket whatever is feeding the circuit. So the positive is going out the negative is coming back and the objectionable current objectionable current would be you know having negative trying to go back on the positive side I did short the ungrounded conductor supplies the load current the low current returns to the source via the grounding conductor and the rest of the grounding and bonding system including the equipment grounding conductor, metallic water pipes, metallic gas pipes, metal raceways and building steel generating potential differences to the ground. Section 20 to 42.30 permits the interconnection between the grounding conductor and the equipment grounding conductor by regular operation of surge protective device during a surge. Note that the grounded conductor requires insulation despite being grounded. Otherwise, its current would pass through the metallic structure. It contacts creating objection, oak objectionable current two 50.6 I have a national electrical code book. Section B permits alterations of the ground and connections to stop the objectionable occurrence first confirmed that it is objectionable. If that’s the case, then the NEC allows one, one or more of the following changes. Remove one or more of the grounding of bond or bonding connections but not all. change the position of the grounding or bonding connect Issues break the continuity of the conductor or path producing the objectionable current adopt other corrective measures only if they are acceptable to the authority having jurisdiction to 50.6 C style states that the current that current through grounding and bonding conductors under normal conditions like a ground fault and those resulting required grounding and bonding connections are not objectionable. Two 50.6 D indicates that electronic equipment cannot be installed on AC systems or branch circuits lacking equipment grounding conductors, current introducing electromagnetic interference or data errors and electronic equipment or not objectionable. Two 50.6 e permits a listed isolator device to block objectionable DC ground currents from cathodic protection systems in the equipment grounding conductor pat this is the way the ground floor fault current return path will perform correctly for AC while blocking DC two 50.8 Section Two 50.8 This suck This section covers the permitted and not permitted methods to connect grounding electrode conductors and equipment grounding conductors and bonding jumpers. The list two 50.8 a list the permitted methods as follows pressure connectors terminal bars pressure connectors is listed as grounding and bonding equipment exothermic exothermic welding CAD welding machine screw type fasteners thread forming machine screws connectors as a part of a listed assembly other listed methods and I want to go back thread forming machine screws. That does not mean a self tapping screw is not the same thing that is not the same thing. I had an inspector call my guys on it the other day and I had to go back and put a quarter 20 with a nut and two washers on a on a ground bond jumper. Okay. So, two 50.8 B highlights soldering as a not permitted method section 250 dot 10 this section requires and clothing and metal wood or equivalent protective covering of all ground clamps and other fittings exposed to physical damage to 50 dot 12. This section requires cleaning all contacts services on the equipment to be grounded or bonded removing non conductive coatings from threads and other contact surfaces such as paints lacquers enamel or the like is vital to obtain good electrical continuity, it is also valid to use fittings designed to make such removal unnecessary. So I’ve been in the trade 3537 years something like that. And that is something that we always did on commercial sites, we would take a wire brush and clean back building steel to where it was to the bare metal and then we would drill a hole in there and bolt you know a lug with our grounding electrode to the steel. And so anyway, that is something that I have experienced with for years and years and years. This is George with our electrical services. I am the surge protector guy, and I am your Gainesville Georgia electrician. So one thing you know, there’s a lot of technical terms. But the best thing you can do for yourself if you’re unsure about grounding is get you a copy of the National Electrical Code and read it if you don’t understand what you’re reading, get a dictionary, Google it, continue to go through it until you get a better understanding. It’s taken me 3537 years to get the understanding that I have and I by no means do I know it all. Thanks

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