Hi i am new to this forum. I am not an electronic engineer but have an interest in this area as a hobby.
I have a question that left unanswered even though i scoured the vast internet for the answer
I have an electronic device which is powered via AC to DC power supply. What happen if the PCB board ground terminal is connected to metal casing via the stand off nut. And in turn the casing is connected to earth of the AC power. Will there be any problem such as leaking current that can damaged the electronic components?

Thanks

 

Welcome to AAC!

I have an electronic device which is powered via AC to DC power supply. What happen if the PCB board ground terminal is connected to metal casing via the stand off nut. And in turn the casing is connected to earth of the AC power. Will there be any problem such as leaking current that can damaged the electronic components?

All that does is connect circuit ground to earth ground.

 

If proper galvanic isolation exists on the unit then it is not always necessary to connect to earth ground, especially if after the isolation it reverts to low voltage, but if the unit does have the common of the DC grounded it is not usually a problem, is this already in place? or something you are thinking of doing?
What is your location?
Max.

 

Welcome to AAC!
All that does is connect circuit ground to earth ground.

yes this is what i mean, should i try to isolate the stand off nut (DC ground) of the pcb board from the earth shielded chasis

 

If proper galvanic isolation exists on the unit then it is not always necessary to connect to earth ground, especially if after the isolation it reverts to low voltage, but if the unit does have the common of the DC grounded it is not usually a problem, is this already in place? or something you are thinking of doing?
What is your location?
Max.

the problem with the chasis is it contains AC powered motor which is earth grounded, so when the AC powered motor is bolted to the chasis, the chasis is earth grounded. I am concern that the electronic component has DC ground (common) leak to the earth grounded chasis. If it does, will that be a problem?

 

It should not be a problem IMO.
What exactly is the 'Electronic component' consist of?
Earth is just a reference point, normally there is no 'leakage'.
Max.

 

It should not be a problem IMO.
What exactly is the 'Electronic component' consist of?
Earth is just a reference point, normally there is no 'leakage'.
Max.

its an arduino board with sensors and cpu and ICs and such. I got my answer but i would love if someone can explain to a layman like me. AFAIK ground is 0 potential and earth is 0 potential. Does that means no current will flow from DC ground to earth?

 

Yes.
Here is one general explanation, It is mainly done in electrical power installations for safety reasons.
Ground Practices
Note the difference between using the earth as a reference and a conductor.
Max.

 

Yes.
Here is one general explanation, It is mainly done in electrical power installations for safety reasons.
Ground Practices
Note the difference between using the earth as a reference and a conductor.
Max.

Thanks max, i will make sure to read the article thouroughly

 

electrical power installations for safety reasons

 

OP: ... suggest grounding circuit board , chassis ground, and wire to earth ground at a single connection point, as a matter of 'good practice'. It may be interesting to note that electrical currents other than DC, higher frequencies, that is, flow near the outer surface of a conductor. Consequently, if you are working with radio frequencies, you would want to use stranded wire to conduct any currents between your working platform and earth ground. The multiple conductors in stranded wire possess more outer surface area than a single conductor wire.

 

OP: ... suggest grounding circuit board , chassis ground, and wire to earth ground at a single connection point, as a matter of 'good practice'. It may be interesting to note that electrical currents other than DC, higher frequencies, that is, flow near the outer surface of a conductor. Consequently, if you are working with radio frequencies, you would want to use stranded wire to conduct any currents between your working platform and earth ground. The multiple conductors in stranded wire possess more outer surface area than a single conductor wire.

on the last statement is to increase grounding of noise especially high frequency right? however, there is no way to do this as permanent installation in my place is using solid core wiring and at the end of it is the big solid copper pole going through the soil outdoor. I suppose i can do the thin stranded copper wiring on the device itself. But i do hope the facility solid core diameter for earth wiring is big enough with big enough surface area.

anyway my initial question was regarding concern of ground of dc circuit (-ve terminal) connected to ground of AC circuit which is earth (connected to the soil). Because my DC powered device chasis is bolted to AC powered device chasis. If any problem may arise from them, what will it be? I have yet to fully understand this problem, thanks.