Power supply reliability 240v vs 120v - Page 1
Forum section: electronics / beginners

author: Zyle
author_rank: Newbie
timestamp: February 01, 2017, 11:24:37 am
content: Hey guys I have a bit of a newbie question regarding hardware reliability in different regions. Specifically power supplies for things like PC's and servers.I'm curious as to weather the life expectancy of a power supply is lower in the higher voltage regions like the UK/Europe/Australia. I watch a lot of hardware review videos before making any purchases but the majority of them tend to be from north america, which obviously has a lower voltage supply.I feel that in a lot of cases power supplies just don't seem to last as long as I expect them to before weird things start happening or even complete failure. I know (good) manufacturers will spec their power supplies properly for the correct regions and it's not a dig against them for the most part (although some of them are terrible!).Is the higher voltage supply in these regions not putting any extra stress on the components at all? No extra heat dissipation or something to that effect? Could this effect other components in computers and servers too? I've had a look around an no one really addresses this anywhere at least my google/youtube searching hasn't thrown up any useful results beyond suggestions of using a UPS or power conditioner.Any insight would be appreciated, and thanks in advance.

author: Ian.M
author_rank: Super Contributor
timestamp: February 01, 2017, 11:32:26 am
content: A PSU operating on 230V PSU has half the input current compared to one on 115V.As long as the PSU has an adequate voltage rating for all components for 230V operation, its probably less stressed than when it is switched to or has auto-adjusted for 115V operation. Remember, resistive losses go with the square of the current so doubling the current is four times more stressful.

author: tatus1969
author_rank: Super Contributor
timestamp: February 01, 2017, 11:35:11 am
content: it depends on the type of PSU that you are looking at. Today's ATX supplies typically come with active PFC. They step up any input voltage to ~400V DC. A lower input voltage leads to higher currents in the PFC stage, lowering efficiency.Smaller and simpler PSUs do not have active PFC, so you'll have components that see less voltage stress. But also here, efficiency goes down and heat dissipation goes up with low input voltage.

author: Zyle
author_rank: Newbie
timestamp: February 01, 2017, 12:00:22 pm
content: That is interesting, how well do modern ATX supplies handle noise on the input. Also would using a UPS/Surge Protector/PDS add noise to the line as well? Maybe that might be the issue i'm seeing. Most of my knowledge is in 1's and 0's and not being a sparky things like this can stump me. I've gone through 3 different power supplies over the past 20 months or so in one particular system and none of them were cheap supplies by any means. The cheapest was about £110 an EVGA supernova 750W supply, and that one actually lasted the longest. Power monitor on the input showed about 450W under load so i dont think its that i underspecced either.

author: RGB255_0_0
author_rank: Frequent Contributor
timestamp: February 01, 2017, 12:10:28 pm
content: Could just be really unlucky. But perhaps there's some issue in the mains wiring (brown outs)?

author: Kjelt
author_rank: Super Contributor
timestamp: February 01, 2017, 12:39:49 pm
content: What are the failures you encounter ? Fuses blown, Overvoltage ? The switch failing, what exactly?The only thing I have a problem with PC power supplies is the inrush current. I use a pc powersupply for my domestic led lighting for over 5 years and I switched each of them on with a 10Amps decent quality relais. Dayly operation so 400 switch on/ 400 switch offs per year.Well after a year the relais contacts were totally corroded and sometimes they refused to shut off. So now I use a 10kW industrial relais (you can hear it switch on in the house) and have absolutely no problems, so I can imagine that everything before the PFC like the switch or connector could have some issues so like to know what broke, you can open the PSU and make pictures post here where there are brown areas or worse, at least we have a notion what failed.One thing to look for is that modern PC supplies have a single 12V rails voltage and those are very well speced. From the 12V the PSU often uses own DC-DC converters for each other voltage like the 5V and 3,3V. So if those fail you have a total different case than if the 12V rails fail etc.

author: Zyle
author_rank: Newbie
timestamp: February 01, 2017, 01:08:31 pm
content: Unfortunately i took the broken supplies to the recycling center, there was no point in me keeping them really so I can't take any pictures of them for you. Two of the supplies just refused to turn on after a while, in one case that was about 7 months, and that was a corsair CX750M, and the other was the EVGA supernova. That one lasted about 10-11 months before it failed.Power button on the PC wasn't working, checked the plugs were in securely and everything was switched on. After about 20 minutes of swapping cables around and getting nowhere, i took the power supply out and tried to start it with a jumper and still got nothing so i just ordered a new one to be delivered next day on amazon. That was more convenient for me than attempting to troubleshoot and fix the dead one with little to no practical knowledge of where to even begin.The other, which was a Be Quiet 750w supply actually started switching itself off after about 5 minutes of run time after only a few months of usage. I figured maybe the over current protection was kicking in and making it shut down.Just for reference since i know this may come up, the other components in the PC should not be THAT power hungry. It's just a 4790k, GTX 980Ti and 2 SSD's. It's got 16GB RAM and a NIC aswell, but i doubt they draw any significant current at all.

author: TimFox
author_rank: Super Contributor
timestamp: February 01, 2017, 05:06:43 pm
content: When I started to use switching power supplies, I was surprised to find that the inrush input current spec was usually twice as high for the higher voltage (240 V) input than for the lower (120 V) input voltage. Of course, the steady input current at high input voltage was close to half that for the lower input voltage. This was important for choosing the input fuse or breaker.

author: CatalinaWOW
author_rank: Super Contributor
timestamp: February 01, 2017, 05:12:39 pm
content: ATX power supplies are a prime example of a product built to compete on price. It is not surprising that reliability is less than ideal - regardless of the input voltage.Beyond that, the inherent reliability will depend on how well the system is designed for a particular input voltage. The widespread use of dual input supplies allows for the possibility that a given supply will be more reliable under one or the other voltage range, but I see no underlying principal that would make one or the other more reliable.

author: joeqsmith
author_rank: Super Contributor
timestamp: February 01, 2017, 06:29:06 pm
content: It would be interesting to see some real data for this. I can believe that different parts of the world would have different failure rates. I would not be too surprised if more savvy companies did not have different versions of the same product that were selected based on their destination. I could even believe that even here if we looked across the USA, some states would have higher failure rates. Humidity, temperature variations, number of storms...Interesting problem but I doubt there is a simple answer.

author: Ian.M
author_rank: Super Contributor
timestamp: February 01, 2017, 07:37:18 pm
content: Most of the EU used to be nominally 220V AC but the British Isles were 240V AC. The supply voltages were 'harmonised' to 230VAC by a purely legislative exercise - by specifying tolerances that included the former ranges. Seehttp://coffeetime.wikidot.com/uk-eu-mains-voltage-harmonisationThe UK is still 240V and mainland Europe 220V. 'China Export' PSUs designed down to a minimum cost point for 220V with minimal voltage rating margins on many parts don't last well at 240V (9% higher voltage), no matter if the case sticker says "100V - 250V Universal PSU"

author: Kjelt
author_rank: Super Contributor
timestamp: February 01, 2017, 07:43:47 pm
content: 7 months? You could get a free replacement, you have a 2 year warranty in the EU.I never ever heard that, I would really suspect that the mains might have large spikes or the UPS you are using has something to do with it.The BeQuiet PSUs use A quality caps and very good quality components. They are really not designed for low cost countrary they are often more expensive than industrial psus.

author: LazyJack
author_rank: Frequent Contributor
timestamp: February 01, 2017, 07:54:52 pm
content: Quote from: Ian.M on February 01, 2017, 07:37:18 pmIt's not necessarily 220 in mainland. The nominal is 230, (with appropriate tolerances, which include 220 and 240). At my place for example it is a very stead 230V and yes, it had been 220 before the change to 230 happened. So it is not simply a legislative change.