10A Fuse

[denarced]

Hi,

 

I recently got a new rig and I've been experiencing difficulties when I turn PSU on. If I use the normal sockets in my room (10A), no other device can be on when I turn the PSU on or it'll result in a short circuit. I have been able to turn the rig on and then turn the other devices on.

Today I tried to use the sockets in the kitchen which are 16A and there was no issue.

 

So the question becomes: this can't really be about the fuse? My Nexus RX-8500 850W PSU can't really be that power hungry that 10A isn't enough? At the moment only CPU(i7 3770) and memories were attached. The PSU is brand new and it's the second one as I already had another brand new one (same model). The PSUs were ordered from different shops.

And a bonus question which I'll ask from my landlord's technical maintenance: is is possible that there's something wrong with the whole electrical system? That seems unlikely as well because the building is 10 years old.

 

All comments and help is welcome.

Cheers

[Deddie]

Yes it's the fuse I had the same problem when I got my new PC, had my old PC running on the same fuse and when I turned the PSU of my new PC on, I tripped the fuse.

 

Edit: I think this is because the PSU draws all of it's power for a split second when you turn it on and if you have a 850W PSU it will draw more than that from the wall.

[mvitkun]

Edit: I think this is because the PSU draws all of it's power for a split second when you turn it on and if you have a 850W PSU it will draw more than that from the wall.

pretty sure it doesn't draw the max power of the psu on boot.

[Deddie]

pretty sure it doesn't draw the max power of the psu on boot.

No not on boot but when you flip the switch on the back of the PSU.

[mvitkun]

No not on boot but when you flip the switch on the back of the PSU.

honestly,I've never heard that

[MG2R]

What voltage are you on? If we calculate with 110V (worst case) and we take into account that your power supply isn't 80+ certified, we can calculate the amps it draws on maximum usage with an efficiency of 80%.

 

1) 850W / 80% = 1062.5 W drawn from the wall

2) 1062.5W / 110V = 9.65 A

 

So, If you're running on maximum power at 110V at 80% efficiency, you're maxing out your 10A fuse.

 

Say you're running at 70% efficiency, this would be 11.03 ampere drawn from the wall at 850W.

If the PSU is running at 70%, you would be sucking 10 amp when your system is consuming 770W.

 

Now a 3770 will only burn 77W without OC. Take worst case scenario of 100W with OC. Factor in a motherboard and a hard drive and you have 150W, take 200W worst case scenario. If your system is consuming 200W, you would only be drwaing 10A from the wall when your PSU is running at 18.18% efficiency, which seems highly unlikely.

[MG2R]

No not on boot but when you flip the switch on the back of the PSU.

There is indeed a power spike when you turn a PSU on, but this shouldn't be big nor long enough to cause a breaker to turn off.

[denarced]

So essentially my solution is to just to never turn off the PSU :)

And remember to do it in a correct sequence when I do. I should have a list of steps printed on paper :D

[Quaker]

If I use the normal sockets in my room (10A), no other device can be on when I turn the PSU on or it'll result in a short circuit. I have been able to turn the rig on and then turn the other devices on.

First of all, it would help if we knew where you are located. In North America, a standard wall outlet would be 110vac at 15amps. This sounds like some other system.

 

Secondly, in this case, it's not a "short circuit", just too much current draw. If it is an actual "fuse" that is blowing, try to get your landlord to use a "slow-blow" or "time-delay" fuse, which can handle a brief surge without blowing. If it's a circuit breaker (instead of a fuse) there are also slower breakers.

 

In any case, there will be a brief power surge when you turn on the power supply, as the various circuits "charge up". After it's up and running, the power draw will be normal - so when turning your computer on and off, just use the power button on the front of the computer and shut it down through Windows, and leave the switch on the power supply "on" (1).