Gripe of the day - What is yours?

[Bibio]

0V is not a ground. its the state between positive and negative cycles where there is no voltage. if there were ever to be a DC ''Ground'' this would be it. but because it only happens between each cycle then its not a permanent thing.

modern vehicle wiring so called ''Ground'' is actually a common negative and usually the frame/chassis.

if DC only has Positive and Negative then where is this magical 'Ground'' people speak of... what they should say is Common (COM).

Earth is something completely different and in this country its called Protective Earth or PE for short and is part of the AC mains but usually connected to a stake in the 'earth/dirt' dependant from the incoming Live and Neutral..

problem arises when other country's refer to earth and ground as the same thing.

the term ''ground'' is why a lot of people get confused with vehicle wiring. when people grasp the idea that all wiring is ''live'' until it connects to negative either by the frame/chassis/battery terminal they understand better.

lets take the so called ''ground'' wire that a headlamp bulb has coming out of the other side to the Positive feed. if you cut the ''ground'' wire and insert another bulb in-line then that new bulb will illuminate when the lights are turned on... therefore its not ''ground''. you can also do the same by 'tapping' into the so called ground wire and connecting the other end of the bulb to the frame which is connected to negative.

the frame/chassis of a vehicle is just an extension of the negative terminal of the battery.

yes its a pet hate of mine.. ROFL

[admin]

Originally Posted by garynortheast

Rain. It's just bloomin' dismal. Gonna start building an ark.

Tell me about it. I went to wash the bike yesterday as the sun came out, 10 minutes into the task and I had to hide in the garage as the heavens opened. Sun came out again and I carried on. Then another burst of rain that turned into hail!
Today was another write off. Cold too.

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[garynortheast]

Originally Posted by admin

Tell me about it. I went to wash the bike yesterday as the sun came out, 10 minutes into the task and I had to hide in the garage as the heavens opened. Sun came out again and I carried on. Then another burst of rain that turned into hail!
Today was another write off. Cold too.

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Yep, hard to believe we're nearly into June!

[Sir Trev]

Originally Posted by garynortheast

Yep, hard to believe we're nearly into June!

Got soaked in Brighton yesterday visiting The Monkey. We took out hire bikes (same sort of scheme as Boris Bikes in London) and cycled the two miles to the Marina for lunch. We had to stop under the awning of a shop when the light drizzle turned into full on tropical deluge. It stopped when we got there and of course poured down again as soon as we set off back after the very nice pizza...

[Ruffy]

Originally Posted by Bibio

0V is not a ground. its the state between positive and negative cycles where there is no voltage. if there were ever to be a DC ''Ground'' this would be it. but because it only happens between each cycle then its not a permanent thing.

modern vehicle wiring so called ''Ground'' is actually a common negative and usually the frame/chassis.

if DC only has Positive and Negative then where is this magical 'Ground'' people speak of... what they should say is Common (COM).

Earth is something completely different and in this country its called Protective Earth or PE for short and is part of the AC mains but usually connected to a stake in the 'earth/dirt' dependant from the incoming Live and Neutral..

problem arises when other country's refer to earth and ground as the same thing.

the term ''ground'' is why a lot of people get confused with vehicle wiring. when people grasp the idea that all wiring is ''live'' until it connects to negative either by the frame/chassis/battery terminal they understand better.

lets take the so called ''ground'' wire that a headlamp bulb has coming out of the other side to the Positive feed. if you cut the ''ground'' wire and insert another bulb in-line then that new bulb will illuminate when the lights are turned on... therefore its not ''ground''. you can also do the same by 'tapping' into the so called ground wire and connecting the other end of the bulb to the frame which is connected to negative.

the frame/chassis of a vehicle is just an extension of the negative terminal of the battery.

yes its a pet hate of mine.. ROFL

Perhaps we share two gripes? That (i) terminology is often inaccurate and misleading, and (ii) people don't understand electrical systems as well as we'd like.

"Ground" and "Earth" are often used interchangeably (and I accept wrongly in some cases) because the origins of the terms date back to systems being literally 'grounded' by electrically connecting part of it to the ground of Planet Earth. AC or DC system, the 'grounding' principle is the same. I agree that 'Common' is a better term for a lot of applications.

On terminology, a DC source really only has a high potential and a low potential terminal. Neither is technically fixed as 'positive' or 'negative' and both can be dangerous unless a stable reference point is established. This is usually done by convention against the ground we stand on, earth potential that is usually taken as 0V (though it's not always as simple as that*)

(As I'm sure Bibio knows, but for the benefit of future knowledge searchers) Vehicle systems can be positive or negative 'common', depending which battery terminal is connected to the frame/chassis. "Negative earth" is the most common term heard nowadays, although it's a dreadfully inaccurate descriptor. The frame/chassis connection is not necessarily at 'negative' potential nor is it technically 'earthed' (or 'grounded') because there's no direct electrical connection to the Earth.

[*For the general reader, Earth potential voltage level is generally considered stable electrically, and conventionally labelled 0V, because it's damp and reasonably consistently low resistance (pretty much anywhere if you go deep enough), but there are circumstances when it can vary significantly. Dry or rocky terrain is often problematic to engineer around. This usually becomes a noticeable problem in high current fault situations in power systems. Research "Rise of Earth Potential (ROEP)", "Touch Potential" and "Step Potential" as a start to find out more about the phenomena and hazards.]


I'm not helping am I? I'm not trying to start a fight but I know I'm never going to be a particularly good teacher.

[Adam Ef]

Third day after the second vaccine and still feeling really really rough. Wiped out.

[admin]

Originally Posted by Adam Ef

Third day after the second vaccine and still feeling really really rough. Wiped out.

That's odd, I'm wondering if you're coming down with something else? I hope it's not covid itself.

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[garynortheast]

I'm a full fortnight after my second dose of the vaccine. The day after I felt quite unwell for about 12 hours and then was ok. But the last few days I have been pretty unwell again, same sort of symptoms. Achey joints, feverish, tired, bit of a headache, constantly cold. No respiratory effects, no coughing or sneezing, or blocked nose. Wondering if it might be a delayed reaction, or something else.

[garynortheast]

Please, just stop raining now. Whatever the point was, it’s been made!

[timwilky]

Bought a video doorbell from ebay. not your ring etc but one that is onvif compatable so it will interface with my home security cameras. Opened it this morning to look.

Fixing box is emty, so email supplier, looked at the chime and no reset button on the back so opened it, No PCB, en empty plastic box, so looked at the doorbell. only two of the 4 screwholes contain screws, opened that, yes another empty plastic box.

OK with knackered hands I aint drilling into brick so gives me a few days. I am guessing supplier had a display pack they mixed up. Lets see how well they do for mistakes, their delivery was excellent next day. good thing I have used paypal and photos sent,