I have the following setup at home:
- one PC (300 W PSU)
- two 22 " TFT monitors
- a speaker system
- one external hard disk with separate PSU –
all of the devices are plugged into a multiple socket with a foot-operated switch (sorry for the poor wording. What's the real name for this ?).
Nomally (and during operations) I am well below the maximum ratings of both the safety fuse and the multiple socket (both rate at 230VDC, 16 A ==> 3680 W).
However, I just yesterday replaced the multiple socket for the second time, because the switch is no longer operational (it is always 'ON'). When I moved into a new home a year ago, I noticed that the safety fuse often triggered when I switched on the multiple socket. I then replaced the fuse with a more lazy one (meaning it does not trigger as fast on power surges)
I suspect that the issue at hand is, that the moment I switch on the TFTs and the computer PSU immediately begin loading their capacitors and I get a really hefty spike.
How could I go about this?
Would it be enough to to attach a ferrit bead to the TFT cables?
Best Answer
It's more likely that the problem you're experiencing is high inrush current. All the gear you have connected is going to use switchmode power supplies, which have characteristic high inrush current when first connected to power as large capacitors inside charge. The inrush current for a switchmode supply can be many times higher than its normal consumption, though only for a very short period (less than a second). See the inrush current row of this table.
It is possible that the combined inrush is enough to damage your board/pop fuses. The only way around this would be a board that can handle more current (may not be practical/easy to find one), or to stagger-start the devices - that, is don't have them all energise at once. Neither of these solutions is ideal, you may need to look at spreading the devices over two boards.