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Lucien Nunes · 30th Jun 2019, 4:15 pm

To put this in perspective - your 1.5mm² cable fused at 13A will probably run twenty of your HiFi systems at once without damage.

I did a demonstration a few years ago with a Philips CD650, a preamp that I can't recall, and a Quad 520 rackmount power amp (note, not a high-efficiency PWM type) driving Kef Concertos (note, not especially efficient speakers). I played rock music continuously at the highest volume I trusted the Kefs to withstand, that could be heard down the street and across the car park. The setup was supplied via.... wait for it.... a 315mA fast blow fuse connected in the mains feed. I.e. less than a third of an amp for more than living-room volume. The only caveat was the switch-on surge of the amplifier was too great for the fuse, it had to be bypassed for a fraction of a second at switch-on to let the reservoir caps charge.

You mention 2.5mm² cable which will carry 20A safely and continuously. There is no need to use this for any normal domestic application fed from a 13A plug. A stage sound system with dozens of large speaker cabinets, powerful enough to fill a hall of 5000 people with ear-splitting rock complete with room-shaking bass, barely takes 20A running load.

30th Jun 2019, 4:15 pm	#21
Lucien Nunes Rest in Peace Join Date: Apr 2008 Location: London, UK. Posts: 2,508	Re: 13 amp fuse for 1.5mm mains flex? To put this in perspective - your 1.5mm² cable fused at 13A will probably run twenty of your HiFi systems at once without damage. I did a demonstration a few years ago with a Philips CD650, a preamp that I can't recall, and a Quad 520 rackmount power amp (note, not a high-efficiency PWM type) driving Kef Concertos (note, not especially efficient speakers). I played rock music continuously at the highest volume I trusted the Kefs to withstand, that could be heard down the street and across the car park. The setup was supplied via.... wait for it.... a 315mA fast blow fuse connected in the mains feed. I.e. less than a third of an amp for more than living-room volume. The only caveat was the switch-on surge of the amplifier was too great for the fuse, it had to be bypassed for a fraction of a second at switch-on to let the reservoir caps charge. You mention 2.5mm² cable which will carry 20A safely and continuously. There is no need to use this for any normal domestic application fed from a 13A plug. A stage sound system with dozens of large speaker cabinets, powerful enough to fill a hall of 5000 people with ear-splitting rock complete with room-shaking bass, barely takes 20A running load.