Why ground is represented with 3 lines?

why ground symbol in circuits is represented using 3 lines?
i mean is there any specific reason or we can use more than 3?

'Grounding: Terms and Symbols'
Problem: There are different symbols and terms for grounds and references. What do they all mean?
https://digital.ni.com/public.nsf/websearch/11BE00780D41622686256BE5006F04CF?OpenDocument

Regards,
IanP

the ground is a pictorial representation of an earth spike
an earth spike is a true ground and this is why its used

forinstance under mains supply local area step down transformers
is a very large one the transformer sits on and is usualy quite deep
around 2-3 meters

3 lines represent 3m length?
is that what u r trying to say?

It is just a symbol! Nothing more nothing less... just symbol!! You can draw as many line as you wish, but its odd. Why dont you ask "How many pike should a resistor sign have?" or "How many loop for inductor size?".

Why a star has 5 point? Why not six?

different symbols are used for different purposes.

sudarshan_onkar said:

3 lines represent 3m length?
is that what u r trying to say?

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No way. its just a representation.
I have recent installed WLL MSC and we are using 8 Earths/Gnds for different puposes. We dug to the water level (almost 60 feet). When you dig less, like upto 3meters, then u will have to take care of the earthing point; i mean u wil have to add salt, coal etc. When u dig to the water level, u leave the earthing point un-attended.


Naveed

Hi i think it is merely a symbol to represent GROUND, during schematics design we are using different type of GND symbols, but in heavy Powersupplay case aforesaid may be right

From my vague memory, different symbols are for different types of grounds....digital ground, earth ground, etc. :|

pmin said:

From my vague memory, different symbols are for different types of grounds....digital ground, earth ground, etc. :|

Click to expand...

No dear, its not like that..


Naveed

I've always felt that there is a lot of confusion and misunderstanding about terms and symbols used in many electronic, electrical and wiring diagrams. Most times a diagram is not specific in defining how or why they are using specific 'ground' symbols.

I like the term circuit common for use within a circuit diagram, but that does leave undefined (but better then misdefined!) if the circuit common is at the same potential as or wired to a local true ground potential.

As an example only circuit common would accurately describe a portable battery powered device, no implied or required reference to true ground required. In such case what is the proper symbol(s) that should be used? Common and ground are not always the same.

True grounding systems can be quite complex and expensive to design and install correctly. I've seen tens of thousands of dollars spent on the grounding system used on a process control center for oil refinery process plants. Multiple ground rods installed around the circumcise of the control building. Different 'ground user's' would have separate cables to a specific ground rod:

'Logic ground' that wired to DC power supply common connections for electronics equipment.

'Safety ground' wired to all exposed metal cabinets and electrical panels.

'AC ground 'wired to the ground/neutral connections in power distribution panels.

Sometimes all the ground rods would be connected together with a dedicated cable and other times they were not tied together, go figure!

I've heard EEs disagree on details of such over-all designs and reference guides can be conflicting or unclear in their definitions and recommendations.

Different users tend to have different concerns or requirements on grounding systems. The AC power people want to talk about max fault current requirements and NEC rules. The Computer and control EEs want to talk about maximum ground loop potential elimination.

I guess what I'm trying to say is that the variation of symbols is just the tip of the iceberg, it really can be a complex subject that even the pros can struggle with.

PS: And that doesn't even touch on the subject of RF ground requirements for certain antenna installations requiring a good 'ground plane' for a specifc operating frequency ;-)
Lefty

GND IS COMMON FOR + SUPPLY, -VE SUPPLY AND SIGNAL INPUT. HENCE 3 LINES. THIS IS MY OPENION. IAM ALSO NOT SURE....

It is only a symbol. It is a question to be asked to an artist.