Power cable & fuses

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Also, would the 2.5 be enough to reap benefits on a single spur- I have around 30m of it kicking around somewhere (I only need 8m from consumer unit to hifi :-)

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i believe NOT. regulations, AFAIK, require at least 6mm sq. cable

if you can "manipulate" it, and can find sockets that fit it, 10 mm sq. will result in even lower impedance per unit length. better.

enjoy...

ken

As far as I understand it, a fuse in a particular location has the function of protecting the cable segment immediately adjacent. Thus, in the event of a malfunction, although the equipment itself is always protected by its own fuses, an unfused supply cable would not be protected, leaving it free to melt and burn down the house after the Naim Audio boxes are fried.

Not likely I know, but the idea of having one's insurance claim rejected and having to start again from scratch is distinctly unappealing .
Best;

Mark

(an imperfect
forum environment is
better than none)

I would suggest getting a short lenght of cylindrical brass of fuse dimensions and cutting to lenght, much better then solder.

Matthew

A pair of wires firmly clamped together will blow a 32A fuse/breaker but if its a pair of wires just touching this will cause arcing and produce enough heat to start fires and will NOT blow the breaker as their will be some resistance between them. You must not link out the fuse in the plugs this is STUPID and DANGEROUS not only to you but your family and neighbours.

pete

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If equipment has an internal fuse then the fuse in the plug is not really necessary. The only way you can draw more then the 13 amp rating of the cable (10 on the IEC plug) is to short mains lead and this would blow the fuse on the main fuse board.

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Not strictly true, the plug top fuse is there to protect the cable before the internal fuse, a fault here is unlikely though. If using conventional 30A fuses, with a equipment cable rated at <13A (which many equipment cables are) there is going to be a finite time before the main consumer unit fuse blows. It may be a long enough time to start a fire.

Personally I take the risk, but in a legal manner, just use unfused mains plugs, either 15A round pin, or source 13A unfused plugs (they are available).

Andy.

Andrew L. Weekes
alweekes@audiophile.com

i have a 30A (6mm sq cable) mains spur to my hifi -- i dont really want to tinker (dangerously) around the consumer unit, although i wired our house myself. one thing i will do is arrange for a "good" (i.e low impedance to) earth in the garden.

be very careful playing with mains electricity. we still need you on this forum...

enjoy...

ken

(note: an hour of this time was taken trying to route the rather inflexible and un-cooperative cable)

Early indications suggest that (a) I survived the ordeal, (b) the rest of my house's circuitry still works and (c) my new spur works.

Sonically, it's too early to tell - I'm comparing a hifi that had been on constantly for 6 weeks or more on the lower ring main with a 'cold' hifi on its own spur.

However, early test reveal that the sound is more balanced and musical, with tangible extra detail and a tightening of the bass (which is therefore a bit leaner now).

Cost of DIY: £35, including all bits & bobs plus a socket tester (essential; don't want to blow your kit or even your self up). Useful extras: screwdrivers, stanley knife, insulating tape, straightened wire coathanger.

John

PS. Farting around with the consumer unit certainly brings you up in beads of sweat, but I'm sure the end result will be ultimately worth it (hell, for £35, it's *already* worth it!)

Most recommended!

John

I've sourced 10sq.mm cable, and have the sockets. For anyone else attempting this, the electrical wholesaler was less than half the price for cable than HomeBase - £1.42/m instead of £3.05/m.

The only spare fuse holder in my fuse box is a 15A with screwed-in wires.

I will either replace the fusewire with 30A, or I can get a 45A cartridge fuse from the wholesaler.

I know that cartridge fuses are reckoned to sound worse than fuse wire, but would the 45A rating give a better overall result than 30A wire?

I know that the 45A/10sq.mm cable is reckoned to be overkill, but I think it's possible that the current-draw of 6x135s needs to be dealt with carefully to avoid it spoiling the sources/preamp. (The class B operation of the NAP180-NAP135 range causes high instantaneous currents to be drawn from the mains when feeding large transients to the speakers).

Has anyone tried running their power amps off a separate run of cable? In this case they'd be running off the same fuse in the fuse box, but separate cable runs.

thanks, Martin

That 10sq.mm cable is a pig!

I've knackered my cable strippers, and it's taken me a considerable time to work out how to chop the stuff up without leaving the end looking like the roots on some manic weed. (Strip the outer insulation off, knaw at the three individual wire bundles with pliers, clean up the slightly messy ends with cable clippers, strip back the insulation with cable stipper).

I have 10sq.mm cable from both Homebase & an electrical wholesaler. The Homebase wire is somewhat easier to work, but the wire bundles are definately chunkier on the other wire.

Ideally I would like to terminate the spur with three single sockets with fused 13A plugs. However, I can't find a good way to join up the cable, and even decent three-way sockets are hard to find.

Does anyone have any suggestions for joining this stuff together?

cheers, Martin

P.S. re soldering inside mains plugs - you'd better be damn sure that your solder will pass enough current to blow your main fuse without melting. Could be very dangerous!

Now, all I have remaining to do is to attach the socket to something (at the moment it's not attached, but it's safe (boxed))...

John

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double-up the 2.5mm giving you a 5mm cable....

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No problem, half of the current will go down each cable.

John, why not go for Litz-construction? 10x0.5mm?

Andrew

Andrew Randle
2B || !2B;
4 ^ = ?;

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Personally I take the risk, but in a legal manner, just use unfused mains plugs, either 15A round pin, or source 13A unfused plugs (they are available).

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