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Hey guys,
I recently building a computer with 4 x 6870.. It's almost finished and i am beginning to think that the 1200W PSU will have problems if i plug it directly into an AC outlet? Anyone have experience with this?
thanks

What PSU do you have?

I have been mining months with 3x 5870's and 1x 5970 on one 1200W Antec High Current Pro Power Supply connect directly to the wall pulls about 1100 Watts from the wall and my circuit has a 15Amp breaker which will serve about 1800 watts before it trips.

i purchased this one
http://www.microcenter.com/single_product_results.phtml?product_id=0357383 (http://www.microcenter.com/single_product_results.phtml?product_id=0357383)

My friend had told me that a room only uses 1200W at a time, so I'd have to get a wire connecting to another room if i was to plug in anything else?? Sounds ridiculous to me, but i couldn't find anything about it online.

I have two computers each with a 1500w power supply.  They each draw 1200w measured with a kill-a-watt.  They are both plugged into the same outlet on a dedicated 20amp circuit.  I've been running for a month with no problems.

The only time I had problems is when I plugged one of the computers into a 15amp circuit with other computers.  It ran for 5 minutes then tripped the breaker.  No damage though.

Most rooms have one or two 15-amp or 20-amp circuits though some older ones may be only 10-amp.  One 15-amp circuit can handle about 1800w.  If you have access to your circuit breaker, it should be listed there.

I have two of those Toughpower Grand 1200W PSU's with 4x 5870's each and they have been trusty work horses for over a month now.

Just out of curiosity, what motherboard and chassis do you use to fit 4 double-wide video cards?  Or do you use PCIe extenders?

Not really true, it completely depends on how the electrician wired your house. THe electrician in my house obviously hated me, as literally every room in the house is split across two 15A circuits (the same 2), except the kitchen which has like 100Amps. And there's a 20A breaker that's connected to nothing.

THanks buddy  ::)

I was only speaking for the places where I've looked at the circuit breaker.  I didn't mean to overgeneralize, and I wasn't accounting for bad electricians.  My recommendation, before plugging in 10+ amps, you should check your circuits breakers.  I've had no problem with 2400w on a single 20-amp circuit.  YMMV.

One bad wiring job I've seen was an apartment I lived in several years ago in Allston, MA.  The whole 5 bedroom apartment had two 15-amp circuits.  If we used the AC and microwave at the same time, it would trip the breaker.  Even worse, both 15-amp circuits were connected to a old 20-amp fuse in the inaccessible basement.  So if we spread the evenly over the two 15-amp circuits, we blew the 20-amp fuse and had to wait til the next day to get it fixed.  Only made that mistake once.  Thankfully I didn't try bitcoin mining in that place.

ok thanks for clearing it up. yes i have 15amp circuits so i should be fine.

no extenders---the 890fxa-gd70.. a great mobo.
a VERY comfortable fit though
my case is a antec 902 v3.

I use an AV8 open bench case for Overclocking available from CaseAppeal (http://www.modders-inc.com/modules.php?name=NDReviews&op=Story&reid=316)

http://i54.photobucket.com/albums/g94/V2-V3/Bitclocking/2011-07-03_22-43-27_140.jpg

Just a reminder, a rule-of-thumb is if you're running a 'continuous' load (i.e. mining rig 24/7), you should never exceed 80% of the rated circuit's capacity.  So a 20A circuit at 80% capacity is 16A or 1920VA(W)'s.  It's part of the NEC code.

• BASIC NEC CODE RULES AND DESIGN PRACTICE (http://docs.google.com/viewer?a=v&q=cache:hsuxRm8RP2UJ:www.fs.fed.us/database/acad/elec/greenbook/3_basicdesigns.pdf+NEC+code+80%25+amps&hl=en&gl=us&pid=bl&srcid=ADGEESjJfXWbQxGscdgvTfY-RlEv9JiHC5sMF6VKQQ9qu1_6_lOMeHRj_ES7I4tlbyBjtlLvUzHBQftC5wNK5ydgkiaxi1L6wNfPdgsjAWD_iGN_OUeU3os2ayhL7RNzV3JLCxVg7u1F&sig=AHIEtbQXYX921Iq9EEM5Bgw5yeRWscVCXA)
  

Like most rules, it's 'meant to be broken', but I thought I'd just throw that out there.

Cheers,
Kermee

I have all my rigs plugged into a surge protector - one SP for each rig.  Once I killed a PSU by having it plugged directly into the wall, I suspect a power surge killed it.  If you have a lot of A/C running off the circuit, you will see this surges all the time.  When my a/c kicks on it can make the lights flicker.  You don't want that going into your PSU with no protector, imho.

You don't break the rule when your PSU is specifically designed and guaranteed for continuous delivery of the specified power.
I've seen one recently...

He's talking about your house's electrical circuit, not the power supply.

I plugged THREE 1200W PSU into a 15amp circuit(or is it 20amp? I'm not sure, haven't looked), without issue. Each one usually draw 800W at peak mining usage when monitored with a power monitor. When I plug in the fourth one though, the breaker flipped out.

You guys in the USA have pretty low rated installations. Here in the UK all household sockets are rated at 13Amps = 3100W so plenty of power for the rigs.

For example my flat has 3x 30Amps circuits for the power sockets and 2x 5Amps for the lightning.

This is why we hate 120V ;)

I could of easily run 240V (double-pole) 30A circuits from my breaker but instead I did the equivalent of three 120V (single-pole) 20A circuits that a single 240V 30A circuit would of handled with the same gauge wiring. -- I basically put in nine 120V 20A circuits in the end in which I could of just done three 240V 30A circuits.  For a total of 21.6kW-rated, or 17.28kW @ 80% capacity. (Homes in my area have 200A service).

We get 240V delivered to our homes in the U.S., but U.S. consumer products requiring power are generally 120V.  Generally only large appliances in the U.S. (e.g. clothes dryers) run off 240V.

I was going to run all the mining rig's PSU's at 240V, but decided against it knowing the sooner or later, unless I change the outlet type to something other than standard NEMA 5-15P, I'd end up plugging in a 120V-only device into 240V and instantly fry it... Ended up being more cost effective to just buy the extra Romex and 20A breakers at $2.96 USD a piece then changing out all the AC plugs to 240V plugs.

Cheers,
Kermee

Nice move. PSUs are even more efficient at 240V  :)

Most likely you're on a 20A circuit.  If you were on a 15A circuit and you put ~2400W load onto it, it would probably flip the breaker in about 60 seconds.

Cheers,
Kermee

Don't get me wrong... I'm running my PSU's at 120V still :(

But I'll probably move them to 240V circuits once I think it's time to do so.  But definitely, running a PSU at 240V is more efficient and probably less wasted 'heat'.

Cheers,
Kermee

If meant in general I doubt the validity of this statement.

"could have" or "could've"
"would have" or "would've"