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Grounding question

Russ15

Aug 15, 2011
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I am working on a pcb and have to run some connections to a ground connection. My question is, is it bad to ground multiple wires to one ground connection. In the schematic there are many places to ground wires all over the board, however I was focusing on a certain one because it is close proximity to where my other wires will be running.

Is there such thing as overloading one ground? Thanks
 

davelectronic

Dec 13, 2010
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Ground problem

Hi there. I dont know what your grounding application is on, but in general you can not over load a ground, but if the area is tiny it might pose a problem, is it a common ground, ie most or all ground wires terminate in this location ? is it a chassis ground, is the ground common with respect to nuteral or negative side of the circuit, not just a saftey ground, some more detail needed, whats the circuit in. Dave.
 

Russ15

Aug 15, 2011
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Aug 15, 2011
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The multiple grounds on the circuit I refer to apply to examples like a keyboard, (pin 5 of the header is connected ground) a usb connection (pin 4 is connection to ground) and multiple IC's sometimes having 3 or four legs connected to ground. I can link you to the project www.megadrum.info Thanks for your reply
 

Windadct

May 25, 2011
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May 25, 2011
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Ahh Grounding .......

OK - very common in PCBs to refer to a trace as ground - however in reality it is really a return circuit that is in fact grounded. So depending on the circuits and their loads running a number of "ground" traces to one point can actually sum currents and cause more current to flow in some part of the PCB - I would think that in 99% of the time this is probably a non issue, but if you are dealing with power circuits - possible.

The amount of current that can be brought to a point on a PCB - or more accurately run in a trace is dependent on the size of the trace. My company has a design limit of 150 A DC a PCB ( yes we have some tricks to doing this).

Lastly - dealing with signals as well as power, the key is do not create any "loops" in the ground circuits. If you look at most PCBs - you will note the design does not account for this, but may include a large or all free area to be the ground, generally OK. - it behaves as a single point, but when connecting to anything externally - true grounds should be radial - meaning they go out and end - they do not go out connect to another circuit and come back.
 

davelectronic

Dec 13, 2010
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grounding

Hi again.
Thats a good explanation of grounding issues in your application, hope that post from Windadct answers some if not all the issues for you. Dave. :)
 
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