I normally use this symbol enter image description here in my schematic as my signal ground.
But recently my manager asked me to use this symbol instead enter image description here because the one that I am using is the earth ground and I should use the signal ground instead.

I checked the IEC 60417 standard, which says this enter image description here is the symbol for signal ground.
Then I started checking big companies' data sheets, especially their evaluation boards, and I found that all of them use the first symbol. I am talking about Analog Devices, Intel, TI, Qualcomm, Cypress, etc. Even Altium uses this enter image description here as its signal ground in its tutorial videos.

My question is: why do these giant companies use this symbol enter image description here as their common ground?

  • 14
    \$\begingroup\$ Most engineers, it seems, aren't terribly consistent with it, and use the symbols interchangeably. I only bother to use specific ones when I need to distinguish two or more grounds. \$\endgroup\$
    – Hearth
    Oct 17, 2022 at 3:26
  • \$\begingroup\$ @ThePhoton 's answer is the right one, of course, as far as jobs go! When I was at University in the USA over 20 years ago, we used your preferred symbol for all grounds. Now, I've started using the triangle for signal, the 3 bars for earth, and a third symbol for chassis... There are a lot of older docs, as you pointed out, and so I doubt anyone would be confused by any of them. \$\endgroup\$
    – bitsmack
    Oct 17, 2022 at 3:46
  • \$\begingroup\$ My personal pet peeve. Use the right symbols people!!!! Those 3 types of "ground" aren't the same things at all. \$\endgroup\$
    – Kyle B
    Oct 17, 2022 at 4:09
  • 2
    \$\begingroup\$ Does this answer your question? ISO/IEC Power/Ground Symbol in schematics? \$\endgroup\$
    – jonathanjo
    Oct 17, 2022 at 7:14
  • 1
    \$\begingroup\$ I normally use the triangle for ground, and I add an "A" for analog ground, "D" for digital ground, and "P" for power ground. The other symbols are reserved for chassis and earth grounds. That may be just my personal preference. \$\endgroup\$
    – PStechPaul
    Oct 17, 2022 at 7:50

2 Answers 2


Whether to follow the IEC spec or some other convention is up to each company individually. If your boss says to use the IEC one, use the IEC one.

  • \$\begingroup\$ +1 - this is not electronics issue, it is a workplace issue. If company policy says you do it X way, then you do it X way (unless it is safety hazard or illegal). You don't have to agree with your boss, you just have to do it. \$\endgroup\$
    – Mołot
    Oct 18, 2022 at 19:32

Ground Symbol, which one I should use?

The following would be of help to decide which symbol would be appropriate.

1. Earth ground

enter image description here

This is related to protective earthing of mains operated electrical equipment. It is an installation of earthing conductors that connect non-current carrying metallic parts such as structures, enclosures, guards etc. to an 'earth pit' or a 'ground stake'.

In the event of such metallic parts getting electrified during fault conditions, the fault current flowing through the earth to the neutral would trip MCBs / GFCIs and thereby safeguard personnel, coming in contact with the equipment, from the risk of electric shock.

2. Chassis ground

enter image description here

Chassis ground implies connections to the chassis of electrical equipment in order that it provides a return path for current or serves as a shield.

Chassis ground and earth ground may be interconnected to facilitate protective earthing.

3. Signal ground

enter image description here

Signal ground is a connection to the positive or the negative rail enabling one or the other to serve as the reference point.

  • \$\begingroup\$ The “Chassis” symbol is obsolete in circuit diagrams (IEC 60617). The symbol is only available for printing on equipment (IEC 60417). \$\endgroup\$ Nov 1, 2023 at 4:02

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