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Running 2 power supplies (can it be harmful)

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joey_rjm5

Member
Joined
Feb 1, 2001
For those who have a technical backgound-

I have a 250w powering my 2 hdd and a kenwood cd-rom drive and a 300w powering my mobo and case fan.

My step-dad, who has been in the computer industry for a very long time, told me it might not be a good idea.

This is his reasoning. He says that it might not be good to run a hdd on a seperate power supply because it is being grounded by a different wire. He says that is could mess with the reliability of the system.

What do you guys think.

He said it would be fine to just run fans seperately though.
 
I ran a spare 250w PSU in my system for close to a year. I ran all my fans as well as my HD's and CDRW's on it with no trouble at all. As far as being grounded I honestly don't see how that's a problem. When something is grounded it's grounded, as long as it's grounded thats all that should matter.
 
I think your stepdad is right.
If you take a look to the UNI ISO rules in matter of industrial application, there are a lot of reccomendations obout grounding and using different power sources.
Particullary you cant power two parts of the same machine using two PS.
Moreover remember that PS act as filters for spurious signals and grounding two units together isn't so easy and efficacious: high freq sigs can run trough power lines and made chaos.
It's very hard to stop high frequency spuries (try to put a radio near your case...) and you can't just use a normal cable, but you need a plait of copper.
It's not harmful to use two PS, but it MAY give you problems...
 
Yes but by connecting the ground wire from the second PSU to the first PSU should take care of any of those problems. Like I said I had done this for almost a year with no troubles at all. As long as your still using a PSU to run the other hardware like HD's, Cdroms, and whatever else the signal should still be filtered.

So I'm sorry I would have to disagree with your step dad. But then again everyone's experiences are different. I'm just giving you my opinion on this.
 
The same is true of using one psu, you loose data for power failure reasons no mater how many psu's you use. In fact spreading the load across 2 lessons the likelyhood of one failing.
 
Phil said:
The same is true of using one psu, you loose data for power failure reasons no mater how many psu's you use. In fact spreading the load across 2 lessons the likelyhood of one failing.
That would be true if the two PSU's powered everything in parallel. However, some components run on one PSU and some on another. Seems like something could get damaged if one PSU failed.
 
I don't see how anything could be damaged just because the power is cut. Obviously you would need to run a scandisk just like if the power of a single psu machine failed but unless someone knows otherwise then damage wouldn't be done in the event of a power failure.
And what I meant by spreading the load across the 2 was by running some components on one and some on another, which would be putting less of a strain on either which would reduce the chance of a breakdown
 
Why not just run all your componants off one psu, and all your cooling off another? Thatway, if your cooling psu fails, you don't loose data. You could rig up an alarm if you are worried about loosing your cooling, but I think you'd notice the sudden absence of dB, tho.
 
BrianCapps said:
Why not just run all your componants off one psu, and all your cooling off another? Thatway, if your cooling psu fails, you don't loose data. You could rig up an alarm if you are worried about loosing your cooling, but I think you'd notice the sudden absence of dB, tho.

because even in a case full of fans they would only use about 30W so a 2nd psu wouldn't be relieving the primary one of much load.
Anyway psu's don't just spontainiously fail for no reason, theres no more chance of a 2nd psu running your disk drives and fans failing that the primary psu that was running everything failing.
 
I'd have to agree with phil on this one. If your running your harddrives on the second PSU and it the PSU gave out. All you would have to do is run scandisk to correct anything that went wrong. I've got a Quantum drive that likes to power down every now and then. All I need to do is run scandisk and it fixex all the errors.
And yes running fans only on the second PSU will not take much of the burden at all off of the first PSU. Thats why I ran all my drives on the second when I had that setup. It did improve my 12v and 5v readings quit a bit.
 
bdf24- just because you haven't ran into any problems, doesn't meen somebody else could. It's great that you haven't though. I trust my step-dad though. he worked with electronics in high school, the navy and then went into programming, so he knows his stuff. He's been doing it for about 30 years.

He said that even if it's in parallel it could cause problems, I don't think I will worry about it though, but I do think I should get a bigger power supply, and run everything off that.

About the fans running seperately, they are!

I have a huge room fan set up next to my open case.

I don't see what the big fuss is over the delta 38s:cool:
 
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Ok I'm not going to despute an electrical engineer, so what problems does he think could arrise?
 
joey_rjm5 said:
bdf24- just because you haven't ran into any problems, doesn't meen somebody else could. It's great that you haven't though. I trust my step-dad though. he worked with electronics in high school, the navy and then went into programming, so he knows his stuff. He's been doing it for about 30 years.

He said that even if it's in parallel it could cause problems, I don't think I will worry about it though, but I do think I should get a bigger power supply, and run everything off that.

About the fans running seperately, they are!

I have a huge room fan set up next to my open case.

I don't see what the big fuss is over the delta 38s:cool:

I apoligize if I came off as being stubbern and rude. I can understand your argument. I guess all you can do is try it. If you do run into any problems i'm sure it wont be anything you can't fix. I can see why you would trust your dad with his past electronic experience.
 
I too, believe that I wouldn't run into any problems I couldn't fix.

From what I understood he just said it wasn't a good idea and he said it would be hard to explain to me. So I made him and I don't remmeber much lol! He just said there could be things like data corruption and so forth. He didn't mention anything about it messing up the hardware though and I don't think that could occur.

He is the type that is very cautious and all that so to him it might be a big deal but to me it's not. I was just wondering what you guys had to say about it.

Oh and he isn't really an electrical engineer, he just messed with it a ton. He ended up being a programmer.
 
joey_rjm5, How do you like the Shuttle AK31 rev. 2? I was thinking of maybe getting a new board one of these days. I've heard some good things about that board.
 
joey_rjm5 said:
I too, believe that I wouldn't run into any problems I couldn't fix.

From what I understood he just said it wasn't a good idea and he said it would be hard to explain to me. So I made him and I don't remmeber much lol! He just said there could be things like data corruption and so forth. He didn't mention anything about it messing up the hardware though and I don't think that could occur.

He is the type that is very cautious and all that so to him it might be a big deal but to me it's not. I was just wondering what you guys had to say about it.

Oh and he isn't really an electrical engineer, he just messed with it a ton. He ended up being a programmer.

Like I said I can not think of any reason why there would be complications, granted if the psu powering the HD were to fail then it would be just like powering down without shutting down, a quick scandisk would sort it out. If your dad can actually explain and proove any real complications that wouldn't arise with the failure of a single primary psu then I will accept it is a bad idea. The only problem I could really think of is if you leave the computer running with a seperate psu powering the fans and it failed then the pc wouldn't be being cooled and may fry the cpu, it would crash obviously as the HD would also not be being powered but the cpu would still be left active.
 
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