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I have a home theatre setup with 4 stereo power amps, 2 powered subs, and 2 powered speakers (LF range).

 

I am feeding this setup via a single 15amp power cable from its own circuit from the powerboard, via a 2gpo power point, connected with two 10amp power boards.

 

My theoretical max power consumption from this setup is a lot more than can be delivered by the line feed.

 

My question is, what happens when the actual power draw needed by the setup is more than can be delivered?

 

Sofar none of the fuses have tripped, but would these fuses trip in the first place in such a situation?

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1st I'd say you are never getting anywhere near the theoretical maximum power output from your set-up, therefore it is very likely you are never going to overload the circuit. 

A single 15amp (3600w) line connected to the main power board should also be going via an appropriately sized fuse/breaker & a RCD on the main power board - if its not it is illegal.

I suspect it is also hard to find music tracks that would drive all of your amplifiers (all set to 11 !) at such peak output for long enough time that either the main power board fuse/circuit breaker would blow/trip or the fuses in individual units might blow.    

I think you wouldn't be able to be in the same room as your experiment and I'm not sure all of your speakers would survive.  

If you were able to somehow simultaneously drive every amp to its maximum (or close to it) using a track test or similar to deliberately exceed the draw capacity of the feeder line I'd expect the fuse/circuit breaker to interrupt the power.   

I think the main issues of using strip power-boards to piggy-back connections is as you suspect - overload.  Heating up of cable / fire risk / trip hazards / connection issues (which one is the culprit?) / noise from many connections....... etc. 

Did you change the plugs on the 10amp strip boards to fit in the 15amp GPO power point???  They are not the same size.

Using 10amp rated strip power boards connected to a 15amp outlet isn't a good idea.  It is dodgy as in theory they could be asked to deliver over 10amps and the components in the strip board are not rated for that - goes back to my comment on fire hazard.

         

     

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@frankn

I don't know the specifics, but the switch board has a C16 circuite breaker, the cable is of the 2.5mm² type, but the single dual plug power point is just standard.

I did a quick test with a plug-in power metre and half my system connected to it, using a movie scene which has peak output and higher than normal volume levels, and the ampere usage never risen above 3 amps. So it would seem that the whole peak output of my setup would not go beyond 6amp of usage with higher than normal volume settings.

Not sure if such a meter is accurate enough, but that was a bit of an eye opener.

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On 11/07/2019 at 4:41 PM, Primare Knob said:

would these fuses trip in the first place in such a situation?

Yes.

 

If they didn't there would be more power available  ;)

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21 hours ago, davewantsmoore said:

Yes.

 

If they didn't there would be more power available 

At least until the PVC insulation melted and the house burned down.

 

Audio is not like many other appliances as the current draw from the mains is not constant, unlike say a heater. A 2400W heater will draw 10A constantly. A 2400W amp (and I have 4 of these) if the loudest peak of the material you were listening to was 2400W, then the average would be 20dB less, or 24W, only occasionally rising to full power. A reasonable approximation, and one used throughout the pro audio industry is 1/8 full power, though even that is high for home use as I've never met anyone who's home system is driven as hard as a PA. Not even Terry's.

 

So if your amp is a 2ch 100W/ch unit like many here would use, your average mains draw would be a couple of watts.

 

Most cheap plug in home power units are woefully inaccurate as they expect the current draw to be roughly a sine wave, but a mains frequency 'linear' PSU produces a haversine which throws them off a lot.

 

Image from Rod Elliott's great site.

 

image.png.98e94cdd01c03f42f6dab0ec86273d20.png

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