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Dedicated HiFi circuit design

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25 minutes ago, Muckplaster said:

A 5A circuit will power a 1kW amplifier. How much power does yours have?

Ring circuits are to save copper. They double the current carrying capacity of the cable used. There are no disadvantages of a ring circuit and we are also fortunate that our mains plugs are so well designed. The best in the world in fact.

i must say i'm really enjoying this thread - learning lots !

also enjoying your more detailed posts muckplaster.

may i ask what are your views on some of the more "exotic" choices of ring / spur mains cable ?

https://mcru.co.uk/product-category/mains-products/mains-spur-cable/?orderby=price-desc&v=79cba1185463

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Posted (edited)
8 minutes ago, Turk 182 said:

may i ask what are your views on some of the more "exotic" choices of ring / spur mains cable ?

https://mcru.co.uk/product-category/mains-products/mains-spur-cable/?orderby=price-desc&v=79cba1185463

Load of massively overpriced tosh.

Edited by Tony_J

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38 minutes ago, Muckplaster said:

Ring circuits are to save copper. They double the current carrying capacity of the cable used.

As I mentioned earlier, they do not double the current carrying capacity of the cable they split the load between legs of the ring. On a 32A MCB/fuse the current carrying capacity of the cable used must not be less than 20 Amps. 2.5mm ² on its own can be good for up to 27 Amps.

38 minutes ago, Muckplaster said:

There are no disadvantages of a ring circuit and we are also fortunate that our mains plugs are so well designed. The best in the world in fact.

While I would agree that our plugs and sockets are an incredible design purely invented to deal with our adoption of the ring main, again a clever idea to overcome the situation at the time, but there are many, many disadvantages with the ring main.

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4 minutes ago, Tony_J said:

Load of massively overpriced tosh.

lol

i'm guessing in theory they may "help" but in practice these cables would not offer any sonic improvement !

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Posted (edited)
55 minutes ago, Turk 182 said:

i must say i'm really enjoying this thread - learning lots !

also enjoying your more detailed posts muckplaster.

may i ask what are your views on some of the more "exotic" choices of ring / spur mains cable ?

https://mcru.co.uk/product-category/mains-products/mains-spur-cable/?orderby=price-desc&v=79cba1185463

I’d be interested to see how many of these have the relevant BS or BS EN number to comply with being used for a fixed installation. 

I also see some are screened/shielded, that opens a whole other can of worms.

Edited by Blackmetalboon

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1 hour ago, Muckplaster said:

A 5A circuit will power a 1kW amplifier. How much power does yours have?

Had to look this one up, but my amp in full load 130w

1 hour ago, Muckplaster said:

Ring circuits are to save copper. They double the current carrying capacity of the cable used. There are no disadvantages of a ring circuit and we are also fortunate that our mains plugs are so well designed. The best in the world in fact.

There are advantages and disadvantages to rings, to many to go into here, and that not including the old chestnut of bad workmanship of a broken cable in a ring can cause.

But A 32A ring circuit serving 100m2 uses more cable and therefore takes longer to install, than 2 x 20A radial circuits each serving 50m2 the latter having a higher loading
capacity of 40A.

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As @FrankD said an open ring on one (or all) of the conductors can go unnoticed resulting in one leg of the ring having the potential to exceed its current carrying capacity. 

I’ve also come across many interconnected rings (circuits cross connected so that they are fed from two different MCB’s).

Then throw in the fact that Arc Fault Detection Devices* (AFDD) are slowly being introduced in the UK and they cannot detect certain arc faults on ring circuits but are absolutely fine on radial circuits.

*These are very clever devices that use algorithms to analyse the AC waveform and identify arc faults from normal arcs caused by  switching items on/off.

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52 minutes ago, Blackmetalboon said:

I’d be interested to see how many of these have the relevant BS or BS EN number to comply with being used for a fixed installation. 

I also see some are screened/shielded, that opens a whole other can of worms.

I particularly like the one with apparently the same colour code for live and neutral, never mind the wrong colurs :doh:

As for screening, not in itself a problem. I presume it would be treated the same way as metal conduit in that it would need to be double insulated under the screening. However, the maxiumum current ratings are different for 'enclosed' cables (in trunking and conduit) so it's a bit of a minefield.

And frankly not one I can see making much difference.

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1 minute ago, rabski said:

I particularly like the one with apparently the same colour code for live and neutral, never mind the wrong colurs :doh:

As for screening, not in itself a problem. I presume it would be treated the same way as metal conduit in that it would need to be double insulated under the screening. However, the maxiumum current ratings are different for 'enclosed' cables (in trunking and conduit) so it's a bit of a minefield.

And frankly not one I can see making much difference.

With a circuit such as a radial or ring main it’s will be classed as a fixed wiring installation and the problem with screened/shielded cables is that the screen/shield will be required to be bonded to earth (how that is achieved opens the door to it potentially being classed as a conductive part) and it’s suitability to handle the potential fault currents. 

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I don't think they'll stop mucking about with Electrical Regs until you can plug a hamster directly into a 13amp socket without electrocuting it .

Whilst obviously not recommending it, I suspect that many of us have broken the regs from time to time when installing supplies for our own systems at home.

I know I have ...with too many double sockets  on the end of a spur being the most common offence.;)

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1 hour ago, Smokestack said:

I don't think they'll stop mucking about with Electrical Regs until you can plug a hamster directly into a 13amp socket without electrocuting it .

Whilst obviously not recommending it, I suspect that many of us have broken the regs from time to time when installing supplies for our own systems at home.

I know I have ...with too many double sockets  on the end of a spur being the most common offence.;)

hi smokestack

so as suggested having a line of say 8 sockets all fixed to a wall (to cut out the need for an extension block) would be illegal and potentially dangerous ?!

is this where a thicker more "exotic" ring / spur cable may be of use ?

(basically having something like this below on / in your wall and connected direct to your mains ring / spur)

Image result for 8 way extension lead

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Posted (edited)

My own preference has always been to daisy chain two or three MK unswitched  sockets , with the cable dressed & stripped so that it doesn't need to be cut to link each  socket.

But the point really is that for our purposes, there's nothing wrong with having multiple sockets on the end of a spur so long as it's only the Hi Fi that's going  be plugged into them.

[ I've always subsequently removed all but the one socket  if the system is moved, and so that nobody can later come along and plug in half a dozen washing machines on a boil cycle :D ]

We must not of course suggest that folks complete any of this work themselves, unless suitably  qualified or having enough specialist knowledge  to know what is safe and what's not .

Edited by Smokestack

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Posted (edited)

I got a sparks to fit a length of Missing Link Orbit power cable from the consumer unit direct to a double wall socket from same co. that supplies the Hi-Fi only. Seems to work well....

Edited by monya

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Posted (edited)
1 hour ago, monya said:

I got a sparks to fit a length of Missing Link Orbit power cable from the consumer unit direct to a double wall socket from same co. that supplies the Hi-Fi only. Seems to work well....

hi monya

may i ask how many metres long is the orbit power cable you use in this instillation ?

i believe the missing link sockets are all heavily silver plated.

mark at the missing link praises highly the use of silver as it has the lowest contact resistance i believe, 

Edited by Turk 182

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Between 4-5 metres, under the floor. At the time I was able to buy it off the reel and I expect Mark would supply in that fashion.

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