Re: [Hampshire] [OT] PCs blowing domestic fuses

On 27/08/07, Rob Malpass <rob@???> wrote:
>
> Hi all
>
> [Very ot I'm afraid]
>
> My father-in-law has just come up with another gem - and as it's been
> quite some time since I've done any electronics, I thought I'd ask for
> confirmation of my suspicions.
>
> Apparently he switched on his PC and it promptly blew a circuit breaker
> back at his house's distribution box! Now as I recall, P=IV. I=13 Amps,
> V=240 so unless his power supply is something like 3000 Watts (enough for a
> kettle or electric fire), there isn't much chance of the culprit being his
> PC. There isn't much else in the room (or on the circuit) he uses - nothing
> like a kettle or electric fire anyway!
>
> So I've suggested he:
> a) plugs a kettle into the same wall socket - to see if it trips the
> circuit breaker.
> b) moves the computer downstairs - to see if he can get it to work.
>
> Any other obvious things I can try? Has anyone else had a situation
> where a PC has blown a domestic fuse?
>
>
>

A circuit breaker isn't a fuse...

...and a fuse doesn't blow at the stated current either - it normally takes
150% for a second or something (there are British standards and things)

The circuit breaker (MCB, I presume) will blow if the current delivered on
live differs from the current flowing on neutral by more than a certain
number of mA for more than a certain number of ms. It's possible that the
PSU could have failed live (or neutral) to ground - this will trip the
breaker, as will a huge capacitor or large inductive load (not something
you'ld have without knowing it, because it'd triip every time you turned it
on.

I would normally just put the breaker back in and try again and only worry
if it did it again, of course, I'm not an electrician and if doing this
starts a fire, don't come crying to me ;)

James