Talk:Ground (electricity)/Archive 2

Grounding

The first sentence describing ground in this article is incorrect. Voltages do not need to be measured with respect to ground. Ground is ONLY a single net in a circuit that is defined as zero potential. That is it! There is nothing in there about measurement. It can be convenient to measure with respect to ground, but there are many times you measure with respect to some other net (which is not ground). This is incredibly misleading! — Preceding unsigned comment added by 2603:8000:7701:9703:419E:4E41:DCD:28FE (talk) 04:34, 8 July 2021 (UTC)

Note that the three clauses of the lead sentence are linked by the conjunction "or". The word "ground" can have three possible definitions. So no, voltages do not have to be measured with respect to a ground node, but that is one possible use for a ground node in an electric circuit. --Chetvorno^TALK 04:48, 8 July 2021 (UTC)

Ground and 0V reference are not the same thing and to conflate them is sloppy. Circuit diagrams have three symbols available for "earth", "chassis", and "0V reference". Sometimes all three are needed at the same time. These can be radically different things. Old 1950s/1960s analogue television chassis were commonly live and danerous to work on (if you didn't know what you were doing). SpinningSpark 09:21, 15 August 2021 (UTC)

Changed phrase in lead to "a reference point". How is that? --Chetvorno^TALK 17:13, 15 August 2021 (UTC)

Yeah, I remember those radios and televisions with the "hot" chassis. In the US before polarized outlets if you plugged them in wrong the chassis was connected to the hot side of the line. Don't really know why they were made that way. The chassis needed to be at radio ground, but I would think it could have been bypassed to the line with capacitors so it wouldn't be a hazard. --Chetvorno^TALK 19:21, 15 August 2021 (UTC)

The reason for it was to avoid the expense of a mains transformer. Also, in some regions in the early days the power available was DC which ruled out transformers altogether. On some sets it was not even necessary to plug it in wrong to get mains voltage on the chassis. Those sets had the chassis sitting at half the mains voltage whichever way round it was plugged, which in the case of the UK's 240V put it at 120V.

I don't think your change makes any difference. It is still wrong to call ground a voltage reference. In some cases it is the voltage reference but that does not put a second meaning on ground. Wikipedia articles should be about one thing, and this article is about electrical ground. Having three definitions in the lead is saying the article is about three different things. If we want to say that ground is used loosely to mean something else, we should say so in the article about that something else, or just mention it in passing (or do it in Wiktionary whose job is to collect word meanings). Anyway, that's my opinion. I'm not going to fight anyone over it. SpinningSpark 20:39, 15 August 2021 (UTC)

Changed sentence

This sentence was changed by User:Chetvorno at 07:29, 7 December 2008 UTC.

A connection to ground helps limit the voltage built up between power circuits and the earth, protecting circuit insulation from damage due to excessive voltage.

In principle, I can imagine a secondary of a power transformer that has no connection to ground whatsoever. Charge could accumulate on the circuit, and eventually cause a breakdown of the insulation (between the circuit and ground) somewhere in the circuit. If one side of the transformer secondary is grounded, any static charge on the grounded conductor will go directly to ground, and any static charge on the energized conductor will pass through the secondary coil to ground.

I have not touched the article, because while this may be a problem in principle, I don't know if it is a practical problem, and I don't know if the people who chose the customary power distribution systems took this possibility into account when making their choices. --Gerry Ashton (talk) 15:57, 7 December 2008 (UTC)

This seems like a misleading statement to me. I changed it, but the change was reverted. Grounding is used to prevent static buildup, but not in power circuits. It may be referring to leakage currents. In power circuits grounding is used to provide a path for unavoidable leakage currents to ground, not to "protect circuit insulation from damage" but to prevent metal parts exposed to contact from developing dangerous protentials with respect to ground. --Chetvorno^TALK 21:45, 30 January 2009 (UTC)