I have added a new amp + subwoofer to my system, everything (together with multiple other stuff like my pc, monitors,...) is connected to a single multi socket (switchable). Now whenever I turn it on it triggers my circuit breaker.

When switched on, the amp does stuff(?) before entering stand-by I guess this + the fact that I live in an old house using 1 circuit breaker for 4 rooms, causes it to trigger. If I use the amps power switch and turn it off before turning on the multi socket, switch on multi socket, wait for a few seconds, then tun on the amp on its own everything is fine, so it seems the initial current is to high with my new devices. (Sadly every 2 days I forget to do so...)

Is there anything I can do to solve this (circuit breaker = default B16)? Might a start-up current limiter (as used for e.g. saws and other big machines) work? Or do you know any ready-made solutions that fit in a socket. Cause start-up current limiter are expensive and most timed relais are made for turn off delay, I also thought about using a latching relay (this would basically solve my problem by preventing the amp from switching on, when switching on the multi socket => but I would favor somthing without me needing to press an extra button)

  • "If I use the amps power switch and turn it off before turning on the multi socket, switch on multi socket, wait for a few seconds, then tun on the amp on its own everything is fine" Well, there you go. Actually, turn the amp off before turning the socket off, even better. Or upgrade the electrical service.
    – Ecnerwal
    Apr 23 '20 at 11:32
  • How many watts of stuff is plugged into the multisocket? Apr 23 '20 at 11:43
  • <1600W pluged in, should be fine, also e.g. pc, tv,.. souldn't take to much initial current. the amp has a big transformer. As said it mainly the initial current. Also while turning off the amp before turning off the socket is actually a solution, I forget it from time to time.
    – Darki
    Apr 23 '20 at 11:46
  • Does the circuit breaker have a TEST button on it? Is it your branch circuit breaker tripping, or your RCD? Apr 23 '20 at 14:24
  • It's a branch circuit breaker (I guess? man I have a studied that stuff but no idea how to translate "leitungsschutzschalter ...) B16, our house doesn't have a RCD. At some point we eventually need to add on and re do some of the wiring.
    – Darki
    Apr 23 '20 at 15:33

A B16 Circuit Breaker = Leitungsschutzschalter tolerates big insurge currents, f.e. 4 times 16A = 64A for 1 second. Maybe this circuit breaker is very old or had been damaged by a massive short in the past. A swap of that CB would be inexpensive, below 5 Euro for a new B16.

The most easiest idea would be to insert one or more power line extensions between the socket and the amplifier. That would increase the power line resistance.

If the electric installation is made for it, a C16 or even D16 would tolerate higher insurge currents, but is more expensive.

Another possibility is to add one or more insurge current NTCs in the amplifier's power wiring to decrease the high current, if it is an old amplifier without any. A newer amplifier's NTC(s) could be damaged.

They are normally black coin-shaped elements, see the photo taken from https://www.ametherm.com/ptc-thermistors-vs-ntc-thermistors-for-inrush-current NTC on PCB

It is also possible that the amplifier has a special power switch with a resistor switched in series. When the switching operation starts this resistor will be bridged after a few miliseconds. But in that case there should be a hint in the manual that this unit should only be switched by the built-in power switch and not by a switch of an extension or a wall switch.

  • I replaced the old B16 with a C16 and now everything works fine. I guess the B16 could have been damaged in the past. While replacing it I noticed that our houses wireing is really bad 3 rooms + kitchen + bath = 1 circiut breaker. I also found some burned cables and a heavily damaged connector. For some reason our house has 1 circiut breaker for an whole apartment and 1 for our bell...
    – Darki
    Apr 28 '20 at 8:06

With inrush problems as you have the devices that allow motors to “soft start” won’t work here the transformer based systems vary the voltage and the Variable Frequency Drives VFD’s vary the frequency and voltage depending on the model. The best option would be to add another circuit. I have done this on many homes, pre 1950 this was very common, I try to split the circuit by where the loads are not just the number of receptacles in your case a single split or new circuit would probably solve the problem.

When I say split I mean to break the chain where 1 receptacle feeds another and take a new circuit to the receptacles that were separated from the original chain. I am in the US and our wiring methods may be different but I would do this or a new circuit with a receptacle where your multi outlet is and that would eliminate the inrush problem.

  • Well simple inrush current limiter often simply use a series resistor which gets disconnects after a few ms. (I don't think about something advanced as an inverter here) I guessed this could work, because in combination with the transformers inductance I would expect it to slow down the inrush current? Splitting and basically adding new wires is actually planed for later, when we also add a rcd to our house. About the wiring, actually no one knows how it was done. The owner once did it himself with a friend... we also have annoying ground-loops.
    – Darki
    Apr 23 '20 at 15:39
  • An inductance will decrease the inrush current. But the transformer of the amp most likely is not optimized for small remanence. When the amp is switched off, there may be a huge remanence left in its core. Depending on the polarity and the phase angle pairing of the next switch on moment, the inductance could be only very small resp. the core could be saturated yielding a very high inrush current, which is still increased by the large empty capacitances on the secondary side. Maybe the amp has a special power switch which bridges an anti-inrush resistor during the switch operation.
    – xeeka
    Apr 23 '20 at 18:15
  • Putting a resistance inline can cause additional issues depending on the type of supply. The resistance would have to be a large wattage to be able to handle the load, depending on the type of power supply an inductance can make the problem worse. I am an electrician with an electronics degree. You don’t want to make your power factor worse as that may be part of your inrush problem. If we had the make and model of the amp we could identify the type of supply.
    – Ed Beal
    Apr 23 '20 at 19:10
  • @EdBeal "The resistance would have to be a large wattage" - this is why it is a special switch with built-in resistor and with a special forced mimic/timing to limit the time for the series circuit to a fraction of a second. "You don’t want to make your power factor worse as that may be part of your inrush problem" The inductance is the problem. The series resistor can only improve the power factor - how could you make the PF worse with a series resistor? It was stated that the amp has a "big transformer".
    – xeeka
    Apr 23 '20 at 19:30
  • If it is a switching power supply the issue is having to charge the capacitors and WILL make the problem worse, as I said without the type of supply throwing anything at it is called shot gunning. You can think you have a solution but there is not enough information available. Inrush can be either capacitive or inductive doing the wrong thing causes a brown out condition and can damage the circuits.
    – Ed Beal
    Apr 23 '20 at 19:44

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