PSU for breakfast

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davidjpowell

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I have a new computer that I bought before Christmas. After 6 weeks the PSU developed a fault of some sort that tripped the earth protection on the house electrics.

Supplier duly sent out a replacement PSU which lasted 6 weeks again before the same symptoms cropped up. Another replacement which lasted only a few days.

I have now bought a 'named brand' which was 'eaten' in a matter of hours.

The pc lives in my office (a shed at the front of the house), which is not always heated, although the PC is normally left on and develops a little heat. I did wonder if condensation may be an issue, however the last PSU tripped the circuit only 30 minutes after I had left the shed. I.e. it was still warm so condensation should not be the issue.

I have tried different power lease, different sockets and have tried plugging the failed units in at the house with the same results.

I am baffled, and I suspect the tech's at the company that built it are also. Are there any components which could cause the power supply to do this in a PC?
 
You could try setting the PC up in the house for a few days and seeing if you can replicate the symptoms - at least that will tell you if its an environmental issue or just a dodgy component.


Ade
 
What kind of PC is it? What accessories or peripherals are attached to the PC, did you add anything to the original spec when ordering (DVD burners etc) and what wattage power supply is presently installed/originally supplied?

I think that covers most of the questions!

Oh, have you tried taking one of the failed units apart? Would be interesting to see if it's full of ants or something...
 
Thanks Shude and Ade

What kind of PC is it? What accessories or peripherals are attached to the PC, did you add anything to the original spec when ordering (DVD burners etc) and what wattage power supply is presently installed/originally supplied?

The PC was custom built by DinoPC (just a small retailer). Not added anything internally to the PC, although quite a few USB devices running off it such as Yoke, Rudder pedals etc (I am into Flight Sim).

Power supply was originally 700w EZcool. Latest one was a 700w Cooler Master.

I think that covers most of the questions!

Oh, have you tried taking one of the failed units apart? Would be interesting to see if it's full of ants or something...

I'll have a look at this. I've glanced in and seen no issues, but you never know. I am quite fed up now with resetting clocks in the house...

The retailer is blaming the cheapness of the EZcool and is wanting me to upgrade to OCZ, saying it copes with unstable fluctuations better.

Could have a go at setup in the house, but would be in trouble (again)...
 
Unless the company who supplied you with the PC are being "economic with the truth" a series a failures like this points towards a problem with your house [ and therefore] shed power supply. In particular earth continuity What protection have you got on your computer supply??----- anti surge/antispike/ voltage regulation?? Switch mode power supplies do require a load to function correctly and could in the past rapidly self destruct without it. However most modern PSU's have safety circuits to prevent this.
 
You could also try a surge protector extension lead. That way it should just blow the fuse inthe extension lead rather than your house and if it is power surges causing the problem it will also cure it.

If it was me, I'd probably make sure all the internal cards are properly in. memory, graphics card etc.

Also, what graphics card do you have? If you have a single rail PSU and are running a high power Graphics card, that can make the PSU trip. I tend to get a dual rail in those situations and run the graphics card separately to the other components.
 
Graphics Card is a NVIDIA GeForce GTS 250 1GB.

I have a surge protector extension lead on order - should arrive today.
 
Is the house "trip" that is tripping a residual current device or similar? Could be knackered. Also could be a wiring issue.

Post the type and model of the trip for comments?

We had a similar issue - the RCCB fired sometimes when an automatic floodlight switched on. Changed the trip and no more issues....
 
What about fitting a small ups to the pc, as it might be power spikes etc blowing it up.
 
It is the Earth protection that is fired rather than a individual circuit breaker. The only way to get power back on is a) unlpug the PC or b) turn off the circuit that the PC is on.

And it always happens overnight, never in the daytime.
 
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It is the Earth protection that is fired rather than a individual circuit breaker. The only way to get power back on is a) unlpug the PC or b) turn off the circuit that the PC is on.

And it always happens overnight, never in the daytime.

Whats the make and model of the "Earth protection"? (if it really is an ELCB then you should update it....).
 
I don't think this is a PC fault. I would suspect the power socket supply wiring in the shed, paying particular attention to earthing integrity.
 
Do you have an RCD as a main switch in the fuse board?

Or individual RCBO's?
 
Switched mode PSUs that are used in PCs / servers are notorious for earth leakage due to the way they work. It is not unfeasable for a single device to generate 10 - 15mA of earth leakage current in (un)suitable conditions. Cold conditions are likely to increase earth leakage, as the effect comes mainly from switching the current through inductors (coils of wire), which have lower resistance when cold.

When combined with any other devices you have in your house that could have high leakage current (fridge / freezer on startup, perhaps washing machine / dishwasher), this would easily trip the RCCB, as domestic RCCBs are typically rated for 30mA leakage current. Also bear in mind that as RCCBs / RCDs age or are repeatedly tripped, their trip current often decreases.

As posted previously, it is worth checking / replacing the RCCB in your consumer unit. Ideally your shed would be connected to a dedicated RCCB in a split load configuration, which would mean that if your shed supply trips, it doesn't take the house supply with it! Ask a qualified electrician about this.
 
Switched mode PSUs that are used in PCs / servers are notorious for earth leakage due to the way they work. It is not unfeasable for a single device to generate 10 - 15mA of earth leakage current in (un)suitable conditions. Cold conditions are likely to increase earth leakage, as the effect comes mainly from switching the current through inductors (coils of wire), which have lower resistance when cold.

When combined with any other devices you have in your house that could have high leakage current (fridge / freezer on startup, perhaps washing machine / dishwasher), this would easily trip the RCCB, as domestic RCCBs are typically rated for 30mA leakage current. Also bear in mind that as RCCBs / RCDs age or are repeatedly tripped, their trip current often decreases.

As posted previously, it is worth checking / replacing the RCCB in your consumer unit. Ideally your shed would be connected to a dedicated RCCB in a split load configuration, which would mean that if your shed supply trips, it doesn't take the house supply with it! Ask a qualified electrician about this.

The shed does have a consumer box with RCD's, but does not trip - it's always the house. Seems like I need an electrician.

I'm mystified why it's the one PC though. In the shed/offiice I have a server, laptop, and 4 year old dell desktop, which don't trouble anything.
 
I'm mystified why it's the one PC though.

Its not neccesarily your PC at fault, as said most things give off earth leakage.If you have a 30ma RCD as a main switch this monitors the whole installation and will start to think about tripping before 30ma.

If theres no time delay on your main switch RCD its not going to trip your shed RCD if it was the PC as Earth leakage there will be a lot lower.

Its a shame im not nearer or id pop round and have a look,nuisance rcd tripping is a PITA.

Get a NICEIC spark round to have a look,or better still someone recommended by family of friends.

Marty
 
The computer has now had a thorough check over and pronounced clean. While it was away we did not have a single trip. Computer came back and we had a trip thris morning. There is obvously something about this PC which triggers the earth protection. I'll post a couple of photo's shortly of the breakers.

I am reluctant to get an electrician in, although am getting closer as we only rent. It's not fair on the landlord as it's not really a house problem, but equally a potential drain on cash I can do without with two birthdays around the corner.

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