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So how many BS1362 fuses do you get for seventy quid?

Sparkingchip
Audiophile plug fuses on Ebay 


I'm over run with the ordinary 13-amp fuses and end up throwing them away! Is that for a single fuse?


Andy B.


  • 0

    Andrew Betteridge:

    The objection raised  to having MCBs and RCDs was that they contain coils that caused sound quality issues, but surely a fuse is just a piece of wire?




    Frankly that's absolute rubbish. If the sound equipment power supply smoothing and bulk capacitance isn't good enough to completely isolate the sound system from anything that happens on the ac side (whether interference or supply impedance) then it's a badly designed sound system in the first place, and tweaks like that are answering the wrong question.


    If a complex professional studio can be installed to the wiring regs, which it can, then a simple self contained home sound system definitely can and we mustn't let people get away with dangerous and potentially illegal installations.


    The only area where I might have some sympathy on the mains side is if the user wanted a clean earth. But even then really well designed equipment should allow for separation of the safety earth from any functional (interference screen) earth - although I'll bet most, if not all, audiophile equipment doesn't. I'm sure others on this forum know far more than I do about how to supply a clean earth whilst still staying compliant to the regs.


    Thanks, Andy 


  • 0

    Andy Millar:


     

    The only area where I might have some sympathy on the mains side is if the user wanted a clean earth. But even then really well designed equipment should allow for separation of the safety earth from any functional (interference screen) earth - although I'll bet most, if not all, audiophile equipment doesn't. I'm sure others on this forum know far more than I do about how to supply a clean earth whilst still staying compliant to the regs.


     



     




    BS EN 50310 (IEC 30129) has some good information - the general principle, though, is usually to provide combined protective and functional earthing within a common bonding network. This will best-align with BS EN 62305-series.


    The provision of a totally separated "clean earth" with its own earth electrodes is fraught with difficulty and introduces real safety issues - and anything less that "totally separated" means that the functional earth is susceptible to voltages and currents in the protective earthing system. For example, in order that a separated earth electrode is not influenced by another earthing system, the electrodes have to be many metres away from any and all buried metalwork connected to the protective earthing system - see Figure 16 of BS 7430. This also means that any of the separated functional earthing system becomes an extraneous-conductive-part to the protective earthing system: if it is not "main-bonded" in accordance with BS 7671, it becomes a touch voltage hazard during a fault. And then there are surge protection issues to address ...


    Hence, fully separated functional earthing systems are not often used ... best to adopt good practices for deriving effective earthing (for EMC and noise reduction purposes) using a combined system.

  • 0
    I'm more concerned that they don't appear to comply with BS 1362 ... and in fact, they don't state what standards they do comply with.


    If it's an adapted IEC 60127 fuse, they are not all equivalent to BS 1362 fuses from a fault-current rating perspective !


    No data at all from an electrical safety perspective, in fact ... still, some great reading which has increased my understanding of electricity wink: https://www.synergisticresearch.com/fuses/black/
  • 0
    To build on my previous post with respect to prospective fault current, BS 1362 fuses are tested at a fault current of 6 kA.


    Compare with BS EN 60127-2 cartridge fuses, which are typically only:
    • low breaking capacity - 35 A or 10 In (whichever is greater)

    • enhanced breaking capacity - 150 A (using the low breaking capacity test arrangement)

    • high breaking capacity - 1500 A

  • 0

    Andrew Betteridge:
    And while we're at it! Better get a grounding block.




    I'm still pondering the grounding block.


    Some years ago a couple of plumbers told me they had been to a house and in the loft was a bucket of sand supported on a piece of wood across the ceiling joists and in this bucket of sand there was a foot length of copper pipe with an earthing clamp and earth conductor attached to it that was connected to the front bedroom light fitting to earth it.


    I suspect that is as useful as the audio grounding block in the link.


    Andy B.

  • 0

    Beard Weird:



    Hi Andy, sorry I wasn't being serious, though I know you were quite fond of the consumer goods section! :D



    I thought you made a good point - we don't necessarily need to go that detailed but we should at least have a general "technical discussions other than W&R" forum!


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