Motherboard grounding

[elcoyoteloco]

Hi all,

Every step-by-step I read on system building stresses how important it is to properly ground the motherboard to the case, and yet I keep coming across pictures like the ones below.

My (probably dumb) question is, how are they grounding the motherboard?

Thanks :)

[Jim K Global Moderator]

...by the black wire coming from the PSU. That is your ground. :cool:

[yxz]

  On 05/12/2010 at 18:47, jjkusaf said:

...by the black wire coming from the PSU. That is your ground. :cool:

:yes:

[treemonster]

yeah as above

teh snadoffs in normal ATX spec cases are there to avoid contact with the metal surface inside your case.

often incorrectly installing standoffs for your motherboard can result ina short which will cause your motherboard to not turn on properly.

that's why when if on your first power on the computer doesn't boot people recomend taking everything out of the case and reassemlbling it on a non conductive surface such as a wooden work bench and seeing if it will power on then.

the standoff holes to screw your mobo into your case are placed and designed as to have no contact with the circuitry on teh mobo. they may be insulated with plastic or some other material as well.

[elcoyoteloco]

  On 05/12/2010 at 18:52, treemonster said:

yeah as above

teh snadoffs in normal ATX spec cases are there to avoid contact with the metal surface inside your case.

often incorrectly installing standoffs for your motherboard can result ina short which will cause your motherboard to not turn on properly.

that's why when if on your first power on the computer doesn't boot people recomend taking everything out of the case and reassemlbling it on a non conductive surface such as a wooden work bench and seeing if it will power on then.

the standoff holes to screw your mobo into your case are placed and designed as to have no contact with the circuitry on teh mobo. they may be insulated with plastic or some other material as well.

Makes sense, but why do I keep reading that it's important to have metal standoffs properly placed for proper grounding? If the PSU takes care of grounding, wouldn't it be better to use nothing but plastic standoffs?

BTW, thanks everyone. This has been bothering me for awhile, but I didn't want to ask for fear of looking like a noob :D

[voidpharoh]

  On 05/12/2010 at 18:56, elcoyoteloco said:

Makes sense, but why do I keep reading that it's important to have metal standoffs properly placed for proper grounding? If the PSU takes care of grounding, wouldn't it be better to use nothing but plastic standoffs?

BTW, thanks everyone. This has been bothering me for awhile, but I didn't want to ask for fear of looking like a noob :D

Some computer cases come with plastic standoffs, you can even buy plastic standoffs by themselves. Plastic standoffs tend to break easily, screw threading strips out easily on plastic standoffs also, so that's one reason why metal standoffs are popular.

[Ruciz]

  On 05/12/2010 at 18:56, elcoyoteloco said:

Makes sense, but why do I keep reading that it's important to have metal standoffs properly placed for proper grounding? If the PSU takes care of grounding, wouldn't it be better to use nothing but plastic standoffs?

BTW, thanks everyone. This has been bothering me for awhile, but I didn't want to ask for fear of looking like a noob :D

If they are not properly placed they could be sitting on a 12V bus which if you read that sticker on the side of your case can have like 20A per rail. If this hits a ground point by putting in a metal standoff in the wrong position - guess what? you are going to either pop a fuse, screw the PSU or burn a hole through your mainboard. Maybe all 3.

The problem if you are grounding through the black wires is those are basically 'return ground' for the components and may carry extra noise which could screw with power (ripple) or interfere with comms on the board. The chassis provide additional grounds to dissipate any noise or EMI interference created by using components.

[elcoyoteloco]

  On 05/12/2010 at 19:04, Ruciz said:

If they are not properly placed they could be sitting on a 12V bus which if you read that sticker on the side of your case can have like 20A per rail. If this hits a ground point by putting in a metal standoff in the wrong position - guess what? you are going to either pop a fuse, screw the PSU or burn a hole through your mainboard. Maybe all 3.

The problem if you are grounding through the black wires is those are basically 'return ground' for the components and may carry extra noise which could screw with power (ripple) or interfere with comms on the board. The chassis provide additional grounds to dissipate any noise or EMI interference created by using components.

So could this become an issue if using, say, a wood cabinet instead of a traditional metal case?

(Assuming, of course, that any fire hazards associated with using wood have already been addressed.)

[treemonster]

  On 05/12/2010 at 18:56, elcoyoteloco said:

Makes sense, but why do I keep reading that it's important to have metal standoffs properly placed for proper grounding? If the PSU takes care of grounding, wouldn't it be better to use nothing but plastic standoffs?

BTW, thanks everyone. This has been bothering me for awhile, but I didn't want to ask for fear of looking like a noob :D

see below

  On 05/12/2010 at 19:04, Ruciz said:

If they are not properly placed they could be sitting on a 12V bus which if you read that sticker on the side of your case can have like 20A per rail. If this hits a ground point by putting in a metal standoff in the wrong position - guess what? you are going to either pop a fuse, screw the PSU or burn a hole through your mainboard. Maybe all 3.

The problem if you are grounding through the black wires is those are basically 'return ground' for the components and may carry extra noise which could screw with power (ripple) or interfere with comms on the board. The chassis provide additional grounds to dissipate any noise or EMI interference created by using components.

pretty much this but i don't think it would be that bad.

  On 05/12/2010 at 19:14, elcoyoteloco said:

So could this become an issue if using, say, a wood cabinet instead of a traditional metal case?

(Assuming, of course, that any fire hazards associated with using wood have already been addressed.)

we'd need an electrician tradesman who was also a computer enthusiast to answer that i think.

most countires in western ueorpe and the US and canada have relatively clean power for hte most part unless the electrician who did the work on their house while it was being built was really bad and cut costs as much as possible.

some very high end computer enthusiasts pay a huge premium to have their houses or just their computer rooms rewired with high end fuse boxes and power conditioners and such to have the highest quality electricty and to meet the demands of their ultra high power draw $5k PCs that they F@H 24/7 with when not running benches and playing games at modded IQ settings.

but for the average PC users doing a DIY build with even a fairly high end PC it's not a huge cause for concern imho. just take the time to research which standoffs you should install where on your case before screwing in the mobo and powering it on. can be as simple as doing a first run dry install of your mobo with out screws to line up the standoffs and see which screw holes are missing standoffs.

i have a few screw holes with no standoffs on them on my pc because i rushed a little and just used only the standoffs that came installed in my case. i can see metal bits around the unusued screw holes which i guess would be for grounding to the case. iirc the ones i have used have that as well.

i'll also note that it's a good idea to wear a slittle clothing as possible while doing your build or swapping/installing parts. it's a good idea not to wear anything pure cotton such as wool sweaters that will give off static shocks. always touch teh metal insides of your case from time to time while doing installs or other work on your PC internals. some professionals like to wear anti static bracelets as well.

[elcoyoteloco]

@+treemonster: So, are you saying that if I use only the PSU ground (no standoffs grounding), it shouldn't be a big concern as long as I have a clean electrical source? I intend on getting a high-end UPS with integral battery.

BTW, the reason I'm asking is I'm thinking about getting a carpenter friend of mine to build me a custom wood case, if it's feasible. Otherwise we might design a wood "shell" over a tower chassis, similar to what you would see on older stereo equipment.

[treemonster]

i'm not sure what you mean? are you making a custom wood or plastic case or something?

but i think so. don't take my opinion as 100% though. there are probably others here who are more likely to post during the work week that might be better educated on this topic.

[hdood]

  On 05/12/2010 at 18:52, treemonster said:

the standoff holes to screw your mobo into your case are placed and designed as to have no contact with the circuitry on teh mobo. they may be insulated with plastic or some other material as well.

Not strictly speaking true. Even though they may appear to be isolated from everything, they virtually always connect to a ground plane inside the motherboard and are designed to make a ground connection with the case.

[treemonster]

see i knew i wasn't 100% on this.

[elcoyoteloco]

Okay... sorry guys, I'm still not getting it.

Is it 100% necessary to ground the motherboard via the standoffs, or will the PSU's ground be sufficient?

Thanks for your patience, btw :)

[Hum]

^ The brass standoffs ground my motherboard just fine. :)

[elcoyoteloco]

thanks, hum, but actually I'm asking the opposite. :)

[shiny_red_cobra]

Grounding through the power supply is enough. The motherboard stands are just backup in case the wire stops working, which is extremely unlikely because there are usually a few black wires. I don't know why you would want a wooden case though, I hope it doesn't catch fire or something.

[Guest]

I'd be more worried with the lack of airflow to be honest.

[elcoyoteloco]

  On 05/12/2010 at 22:53, shiny_red_cobra said:

Grounding through the power supply is enough. The motherboard stands are just backup in case the wire stops working, which is extremely unlikely because there are usually a few black wires. I don't know why you would want a wooden case though, I hope it doesn't catch fire or something.

Cool, thanks for a definitive answer. And thanks again everyone for your input, very educational. :)

My friend is a very talented woodworker and will give me a steep discount, but yeah, we're definitely aware that heat will be the critical issue.

Thanks again, everyone!

[TEX4S]

I will be the 1st to admit I know nothing about electricty. When I was in New Orleans after Katrina, I would walk on the roofs of the damaged houses and others would always be saying "careful that wire is hot" or "careful, youre not grounded" - and I am thinking "how do they know that ? and I thought being grounded was bad ?!?" :wacko:

So, no, dont feel like a n00b, I think its a great question, one I always wonder myself.

I can tell you one of the problems beginners will see is when one is inserting the mobo standoffs, they will plug up every hole in the case, not just the ones that particular mobo needs.