PowerPack1500, RCDs, and electrical safety


#1

I’ve woken this morning to find my P10 and everything connected to it is down. Checking the circuit I see that the RCD at the meter box has tripped. I disconnect the P10 from the wall and the RCD does not trip, so something downstream of the powerpoint has a fault causing the RCD to trip. Disconnecting all loads from the P10 the RCD does not trip. Connect my PowerDirector47 to the P10 and the RCD trips. Disconnect all loads from the PD47 and the RCD does not trip. So one of the 14 devices connected to the PD47 has a fault causing the RCD to trip.



[I mention at this point for those who might not know that an RCD is an electrical safety device that removes power from a circuit when a very small difference in current between A and N is detected, i.e. a fault].



This has got me thinking as I’ve just ordered a new PowerPack1500. What if, in this situation, the PowerPack1500 was between my P10 and PD47 (or in-front of the P10 for that matter, i.e. providing back-up power to all loads connected to the P10/PD47). Assuming the RCD would still be operative and trip the circuit, the PowerPack1500 would still be supplying power to a system with a faulty load, and thus present an electrical hazard? Or does the PowerPack1500 have a fault detection capability similar to the RCD in the meter box and in this scenario would not provide back-up power to the faulty load?



Is there a case for RCD to be installed between a PowerPlay1500 (and UPS generally) and the connected loads?



#2

Further development: I suspect the genesis for this was actually an intermittent fault in the P10 which has now turned permanent. This evening the RCD tripped and now the P10 appears to be deceased…


#3

Oh no :-S


#4

Bummer.



Good detective work however.



brodricj said: does the PowerPack1500 have a fault detection capability similar to the RCD in the meter box and in this scenario would not provide back-up power to the faulty load?


Great question. It is fused which should fail if there is a fault downline.



#5

The P10 has failed. I check the fuse and it was blown (a Hi-Fi Tuning Supreme fuse @ $50 each no less) :(( I disconnected all loads, replaced the blown fuse (did I mention it was a $50 Hi-Fi Tuning fuse? :-(( ) with a stock fuse, connected it to the wall and turned it on. Dead (but the RCD did not trip this time). Checked the fuse and it had blown.



So it is confirmed, the P10 has a fault which is causing its fuse to blow. In hindsight this problem has been brewing for a week or so now, with several RCD trips now progressed to fuse blowing.



Anyway, another case for Customer Support, I’m sure it will get dealt with…


#6

Great question. It is fused which should fail if there is a fault downline.


You can still receive a fatal electric shock from a faulty fused device that is not RCD protected (RCD's will trip at 35mA in fault protection, fuses only blow at their rated capacity which are usually much higher than this).

I asked PS Audio this question and the answer was, the PowerPack1500 is not their design and they don't know (which came as a surprise to me because on the back of the unit is the "designed by PS Audio in Colorado" sticker). So they have referred the question to the manufacturer in China.

In the meantime I have ordered an RCD power point tester so I'll be able to work it out myself.


#7
brodricj said: You can still receive a fatal electric shock from a faulty fused device that is not RCD protected . . .

It is possible. Although if one has a GFCI/RCD on the supply circuit this should trip in any event.

As for the PowerPack, I know only of the fuse I mentioned.


#8

…that’s my whole point, even if the RCD trips on the supply circuit to the PowerPack, the PowerPack will go into battery backup mode and thus keep supplying power to the faulty device that tripped the RCD in the first place. Or I suspect that’s what will happen…in which case the output of the PowerPack needs an RCD installed between it and the connected loads (if it doesn’t have RCD protection already, and PS Audio doesn’t know whether it has or hasn’t).


#9

Again, no argument.