Too much current

Balfa

I'm sorry but I can't find a more suitable forum for this post...

Two bedrooms in my house are on one circuit. The circuit is equipped with a 15 Amp breaker that's tripped twice in the last month.

I never thought this would be a problem as I only have two average PCs and that's it. I added up the maximum rated current for each device (bear in mind I'm in the U.S. so 115V AC)...
My PC's PSU is rated for 8A (And it's only a 350W!)
My monitor is 1.4A
My wife's PSU is 6A (Brand new Antec Earthwatts 380 - I thought maybe her old PSU, which had been a bit fluffy since a harsh lightning storm, may have been the culprit, but no)
Her monitor is 1.2A
In addition, her speakers are 0.2A and the router is a little over 0.1A.

That totals almost 17 Amps

I still didn't think these PCs should get near maximum, though... Mine's a Venice 1.8GHz / 7600GT / 1xHDD / 1xOptical
My wife's is a Palermo 1.8GHz / 6600GT / 2xHDD / 1xOptical

Anyway. What can I do? Do I need to get an electrician in who can upgrade the wiring of this circuit, or maybe add another circuit? Should I consider replacing my PC's PSU with a good quality energy-efficient one?

If anyone knows a more appropriate place for this topic, let me know!

Thanks.

ger macc

i would start by replacing the 15 Amp breaker.. and see if it trips again ...it could be defective !!

Avns1s

It's not the consumption of your PC's thats causing it unless you have a faulty PSU that is shorting out occasionally or some other fault. Surprising though that this wouldn't blow the fuse in your plug. Some PSU's also have an internal fuse. I'd be pretty sure though that the nominal power consumption of your PC's on a 15A breaker is not the problem.

Could there be a loose connection on one of the sockets or on some other item plugged in. Or would there be anything else also on this circuit?

It would be rare that the breaker would just beome faulty.

Shiny

There has to be something defective.

there is no way 2 pc's would pull 15Amps.

One time at a LAN party I ran 5 pcs and monitors
from one socket and it was fine.

My PC at the moment is only running at 250watts
at around 1.1 amps (I have a watt meter ):).
The fact that the circuit is tripping is a GOOD thing.

If you upgraded it to 30Amps, the next thing in line to
give out is the fuse's in the sockets which could be
from 3Amps up to 13Amps. That is another problem.

The 'problem component' could end up going on fire before
a 13Amp plug fuse would blow.

Are you sure it is only the 2 bedrooms on the circuit?

Also check what fuses are on the plugs to the PC's and
their monitors. If they are all 13A you could replace them
with 6A fuses, which would be much safer. If the problem
is with one of the PC's then this should show it up.

glynf

15A for a socket breaker sounds a bit odd. How old is the house/wiring & fuseboard?
Most modern houses have 20A MCBs for each radial circuit, that’s a total of 4-5 twin sockets iirc, its been a long time since i looked at a copy of the elec. regs...Both PC's should rarely hit their max full load current. unless you have a faulty PSU.

As mentioned it could also be a defective MCB. If the trip a lot, over time the bi-metal strip that senses the over current can get damaged and cause nuisance trips.
If you feel confident working with electricity you could check all sockets on the circuit ensuring that there are no loose connections, and replace the MCB. Otherwise call an electrician to do it for you.

Balfa

glynf wrote: »

15A for a socket breaker sounds a bit odd. How old is the house/wiring & fuseboard?
Most modern houses have 20A MCBs for each radial circuit, that’s a total of 4-5 twin sockets iirc, its been a long time since i looked at a copy of the elec. regs...Both PC's should rarely hit their max full load current. unless you have a faulty PSU.

As mentioned it could also be a defective MCB. If the trip a lot, over time the bi-metal strip that senses the over current can get damaged and cause nuisance trips.
If you feel confident working with electricity you could check all sockets on the circuit ensuring that there are no loose connections, and replace the MCB. Otherwise call an electrician to do it for you.

Well, like I said, it's in the US, so there are no fuses in the plugs. It's only ever tripped twice, both in the last three or four weeks. The house was built in late 2005, and it's positively riddled with wall sockets.

I should mention that the second time it tripped, I was running prime95 to stress test my CPU, and after my CPU temp settled around 52 celsius, I connected the (usually dormant) case fan to see if it would make a difference in temperature. A few minutes after the fan went on, the whole room died.
Although the first time it tripped I was just playing Team Fortress 2. I don't overclock or anything.

And yeah, my initial thought was something faulty, and because the wife's PSU was humming while off and her PC was doing strange things since being struck by lightning (the same shock killed the ethernet socket on the motherboard and minced a usb flash drive that was connected), I replaced that one. But maybe it's my PSU? It's a crappy no-name that came with my rosewill case.

I'm sure that these two bedrooms have the only sockets on that circuit. I just realised there was also a 1.5A paper shredder, a 0.9A printer/copier, and a 0.16A camcorder charger plugged in but none were on/in use at the time.

I suppose the good thing is that there are so few devices, if it is a fault it should be easyish to pinpoint. I should probably get a wattmeter thingy.

Remember that at 115V AC, current should be pretty much double what you're used to in Ireland, so take that into consideration when making statements like "there is no way 2 pc's would pull 15Amps.". I'm not saying you're wrong - I don't know or I wouldn't be here asking - I just want to remind you that my situation is a little different

Inspector Gadget

Hmm.

Well, considering you're in the US, it's not at all impossible that you're drawing 17A from two PCs; however, (off the top of my head) 15A is seems underrated for a circuit breaker serving several rooms, and fairly average (no offence) PCs drawing about a kilowatt each sounds fishy to me.

To be honest, if this was the case, I'm surprised that the CB isn't tripping when you fire up the machines; usually, that's when the largest power consumption spike (the inrush) happens. Power consumption by PSUs is directly related to two things: the power demanded of them, and their own efficiency. You should probably check out power supplies with Active PFC (power factor correction) and an 80 Plus efficiency rating (http://www.80plus.org/) (like your wife's) to help reduce how much power your system draws. I'd also look at what else is running in the room, and - on the off-chance that it'll help at all - under-volting your processors a little bit.

I also suggest you pick up something you can actually measure the power consumption with - Seasonic's Power Angel, for example. (This is a 110v-only product, so it'll be available and work fine where you are). You may be surprised by what you find out.

Hope this helps,
Gadget

Khannie

Inspector Gadget wrote: »

15A is seems underrated for a circuit breaker serving several rooms

Ya, totally agree with this. Seems very odd for the US to have a room only capable of drawing around 1800W. Some kettles are higher than that!!

Not totally up on household electrics, but is there any way you can have that breaker changed to a higher amp rating?

Balfa

That's a good point about the kettles, but if the wiring is only 14 gauge, it shouldn't really carry more than 15A, which is the point of the breaker in the first place.
I'd rather the breaker trip than the house burn down

watty

US appliances draw slightly more than twice the current.
US sockets are two flat pins with all spurs like old round pin system. No plug fuses.

A 2000W never mind 3000W kettle is impossible in USA unless hardwired into utility supply. Some houses have a separate 220V for cookers, Washer/Dryers etc, but they are hardwired. You can plug twice as much computers into power socket here as in US.

Inspector Gadget

Balfa wrote: »

That's a good point about the kettles, but if the wiring is only 14 gauge, it shouldn't really carry more than 15A, which is the point of the breaker in the first place.
I'd rather the breaker trip than the house burn down

Unfortunately, you're 100% right there. 14 gauge is approx. 2.0mm2, recommended max for that is 15A @ 110/115v, and while I'm not au fait with current Irish building regulations, I'd be surprised if they allow for smaller than 2.5mm2 (which is somewhere between 12 gauge and 14 gauge) in these circumstances. I know I wouldn't.

Gadget

watty

In the UK / Ireland a number of rectangular outlets are on a shared ring main of 2 x 2.5mm sq. cables and a 20A trip. Hence thin flexes 3A or 5A fuse and heavy flex 13A fuse. The system means the plugs MUST have a fuse. A spur system (Everything else) has an individual wire and trip / fuse for each outlet, thus the plugs do not need fuses. The UK/Irish system may have several trips/rings.

Stephen

Inspector Gadget wrote: »

I also suggest you pick up something you can actually measure the power consumption with - Seasonic's Power Angel, for example. (This is a 110v-only product, so it'll be available and work fine where you are). You may be surprised by what you find out.

Another popular 115v device for doing this is the Kill-a-watt.

Anyone know of a 220-240v version? I'd like to find out just how efficient my Seasonic PSU really is

Balfa

Pretty much all U.S. houses have a 230v circuit for oven/drier/HVAC/water heater.
And pretty much all PC PSUs have a switch on the back for either 115 or 230...
Maybe I need to rig up my own 230v circuit for the bedrooms

I'm starting to finally feel the practical implications of Edison vs Tesla, now Damn you Thomas... Damn you!

Effectively it takes twice as much copper to do anything... I wonder if copper keeps increasing in price the way it currently is could there be a push over here to move to 230?
Not likely, but I can dream.

Oh, I looked at both power angel and kill a watt... Does anyone have any recommendations or know which is considered better?

zilog_jones

Khannie wrote: »

Seems very odd for the US to have a room only capable of drawing around 1800W. Some kettles are higher than that!!

Well it's pretty much a non-issue in the US, as electric kettles are very much a (ex-)Commonwealth thing.

Balfa

I have two electric kettles, both are 1500W
Although no-one else here I know has one. But then hot tea isn't too popular in Texas. I'm sure as you go further north there'd be plenty of electric kettles.

So yeah, this isn't fun. There are 24 sockets in these two rooms... They're just trying to rub it in.

Capt'n Midnight

Don't turn on everything at once because the inrush current can be more than the running current. The currents listed on devices are peak, not average so power saving settings may help there.

Also is there any chance it was an RCD / ELCB trip caused by earth leakage or similar. Power saving won't help here.

One option if else fails buy a UPS, this will even out the inrush as seen by the mains. If you live out in the sticks or get frequent power cuts or brown outs it may be worth getting anyway. Don't forget to let the batteries drain a bit every month as constant over charging reduces the battery life.

A brown out means lower voltage so the (switched mode) power supply will draw more current to compensate.

Inspector Gadget

Balfa wrote: »

I'm starting to finally feel the practical implications of Edison vs Tesla, now Damn you Thomas... Damn you!

Well, if Edison had won that debate, you'd be using DC!

I'm not surprised that high-current-draw devices are on a 230v circuit - apart from the daftness of having two different voltage levels being supplied to a single house, unless the supply is not just single-phase - the losses in the cabling due to resistivity (and therefore the wire heating) is reduced by a factor of four for a doubling in voltage, if I remember my Ohm's law.

I really think you need to go measuring to see where the problem is. Is it possible that the length of the cable runs to these sockets are hindering you? Those thin cables will have non-negligible resistivity, especially over long runs (i.e. how far are your sockets from where the mains power enters the house?). Capt'n Midnight's brownout comment is also very relevant here.

Gadget

watty

And 110V in US is just as dangerous as 220V here, because 60Hz is twice as bad for heart as 50Hz. At 15KHz there is no muscular effects at all, only burns.

zilog_jones

Balfa wrote: »

I have two electric kettles, both are 1500W
Although no-one else here I know has one. But then hot tea isn't too popular in Texas. I'm sure as you go further north there'd be plenty of electric kettles.

Oh? I thought only the stovetop variety really existed there. TV and the internet lied to me :mad:

Capt'n Midnight

watty wrote: »

And 110V in US is just as dangerous as 220V here, because 60Hz is twice as bad for heart as 50Hz. At 15KHz there is no muscular effects at all, only burns.

handy info, 20mA at 9V across the heart could kill you too.

maybe the Italian Railways had it right with teh flickery lights

15KHz means we could use very small transfomers and as a bonus only teenagers would hear the high pitched noises from them

Balfa

Inspector Gadget wrote: »

apart from the daftness of having two different voltage levels being supplied to a single house

Actually each house gets two 115v live wires to the mains board, they're just 180 degrees out of phase with each other, so most sockets use either of the lives to neutral, while the 230v appliances use one live to the other live.

I really think you need to go measuring to see where the problem is.

How do I do that?

Is it possible that the length of the cable runs to these sockets are hindering you?

Nahh, these rooms are directly above the garage where the mains board is.

watty

As a teenager "fixing" TVs I had a few 800V shocks. But the Boost rail and EHT transformer run at about 15.625kHz -- fortunately.

230V center tapped actually. So some rooms off one leg and some off the other to balance the load.

@Balfa, I think you need a qualified Electrician. esp if your house is Timber.

Anti

I'd reccomend you buy a petrol generator. Slap on a HKS exhaust system. And a blitz air filter. If your feeling plush you can always bore the head......


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