wrote in message
oups.com...
I'm having intermittent problems with either the main breaker or the
ring main breaker tripping out.

snip

The ring breaker has been changed for another 30A and it still tripped
either itself or the main - the ring breaker has also been upped to a
40A and it still exhibits the same intermittent trip issue when
different workstations are powered up.

The only component not changed is the main breaker; do they have a life
span of x years? - the board takes type 2 breakers which I have been
told are like rocking horse droppings to find these days (seams to be
plenty on ebay) - I'm tempted to get the whole board updated.


Lets get this right. You have an RCB which is the "main" incoming switch
for your consumer unit and an MCB for the ring circuit.

That on occasions either the MCB or the RCD will trip if you turn on a
workstation.

First of all when you say "turn on" a work station, is power already going
to the PS and you're hitting the (soft) start button, or are you turning on
the switch on the PS itself? Secondly does the MCB trip with just one or 2
workstations connected? Are all the workstations the same?

I've had an RCDs trip when I've switched on at the PS which I assumed was
due to suppression within the PS causing asymmetric current spikes on live
and neutral. Hitting the soft start button on the front has never caused me
any problems. Also, if needed, switching on at the wall helped because on
mains socket outlets only the live is switched.

For the MCB to trip it must be sensing some large current. The only thing I
can think of is that some old power supplies had awful power factors, making
the sensed current higher.