EGC

Master Nater said:
so instead of providing GFCI protection to all of the required protections listed under 210.8, why don't you go and get a 1:1 transformer and begin cleaning up your circuits, and taking away the reference to the earth, on all of your potential electrocution hazards? having them isolated from the earth, would eliminate any shock hazard, right?
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Correct. An ungrounded system is better in many ways. Clearly however it is not the topology we have in the states.
 
don_resqcapt19 said:
.one of the issues in changing a long standing code rule is lack of technical substantiation and testing results. They all know that having a full size EGC in each raceway of a parallel set is not required, but until someone spends the money for testing to prove that you don't need a full size EGC in each raceway, the code will not be changed.
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whats interesting is when they upsized the wire sizes in whats now T250.122 1968 there was not much 'technical substantiation' and Canada never followed suit (I think it was proposed there a few times),
If we compare the NEC 250.122 with the one in Canadian electrical code there are a few minor differences like a 14 AWG is allowed as a EGC for a 20A circuit and a 12 for a 30A circuit.
I have long thought it would be better to reconcile and harmonize these equipment grounding tables, as we then it would be easier for cable manufacturers to make one North American cable, then there would not need to be NM-B and NM-D etc.
 
Master Nater said:
so instead of providing GFCI protection to all of the required protections listed under 210.8, why don't you go and get a 1:1 transformer and begin cleaning up your circuits, and taking away the reference to the earth, on all of your potential electrocution hazards? having them isolated from the earth, would eliminate any shock hazard, right? you don't have to worry when that lightning storm rolls through.

(be sure to update everyone, after the first storm how things went)
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I'll make a deal with you. You provide the materials and I will do the labor. I'll put my house on an isolated transformer and live stream every time there is a storm and the whole world can see if my home entertainment center blows up.
 
tortuga said:
whats interesting is when they upsized the wire sizes in whats now T250.122 1968 there was not much 'technical substantiation' and Canada never followed suit (I think it was proposed there a few times),
If we compare the NEC 250.122 with the one in Canadian electrical code there are a few minor differences like a 14 AWG is allowed as a EGC for a 20A circuit and a 12 for a 30A circuit.
I have long thought it would be better to reconcile and harmonize these equipment grounding tables, as we then it would be easier for cable manufacturers to make one North American cable, then there would not need to be NM-B and NM-D etc.
Click to expand...
Not sure why we increased the size of the EGC for circuits 30 amps or less. I can't imagine that there is any technical reason why the EGC for circuits 30 amps of less has to be the same size as the ungrounded conductors and the EGCs for larger circuits is substantially smaller than the ungrounded conductor.
 
Master Nater said:
you left off the second half of my post. feel free to read it again.
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So i read it again, and i guess i am not sure what you are proposing in that thought experiment. You want to use a transformer to serve a device with an ungrounded system? What about equipment grounding, would that remain bonded? You seem to be using system grounding and equipment grounding interchangeably, as we were initially talking about equipment grounding.
 
electrofelon said:
So i read it again, and i guess i am not sure what you are proposing in that thought experiment. You want to use a transformer to serve a device with an ungrounded system? What about equipment grounding, would that remain bonded? You seem to be using system grounding and equipment grounding interchangeably, as we were initially talking about equipment grounding.
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The discussion moved away from what to call equipment to grounding to a philosophical debate about earth grounding. I have been sloppy with some of my comments about solidly grounded systems and ungrounded systems so that hasn't helped keep the discussion clear.

As I understand it Master Nater has a position that a building, more specifically a house, is safer with a connection to the earth. I am of the opinion that a house could be just fine with no connection to earth. The only way one could get there for sure is to put the house's electrical through an isolation transformer, which I am willing to do. The upside would be I could never get shocked so there is no need for any GFCIs in the house. The down side would be a thunderstorm could do some damage to items in the house that use electricity and there would be an elevated level of danger from static and capacitance to the inhabitants.

I understand the reasons for earthing and I understand there is some overall benefit to it. I am quite happy living in a world that uses earth grounding and equipment grounding together. I just see the earthing part of it as good but not vital to safety. If I could change anything about our electrical in the Americas it would be to transition away from line to neutral circuits.
 
don_resqcapt19 said:
Not sure why we increased the size of the EGC for circuits 30 amps or less. I can't imagine that there is any technical reason why the EGC for circuits 30 amps of less has to be the same size as the ungrounded conductors and the EGCs for larger circuits is substantially smaller than the ungrounded conductor.
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Would it be that many of these are long and they were concerned about V drop?
 
Sometimes I surprise myself. Most of the time I think I am out of my league and compared to Don I am. I do like some of the logic though.
He is a guy qualified to propose code arguing bond or ground which I figure is over my head.
He says he doesn't know why they require this and made it clear I don't either. So it's neat to find something relatively common he doesn't know any more about it than I do.
 
I would guess some of the calculations might be quite complicated and even situational. We upsize egc all the time for V drop. I read about every manual for Miller Hobart they had at one point and opened the book along with it and although this is only semi related its worth noting some of the details concerning egc sizing on these small circuits. (Breakers in AC and welding equipment often larger than the ungrounded ) etc,,, this is generalization.
 
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