10 meter power cable with broken earth strand.

[williamwright]

I'm surprised they don't use guineas.

Bill

[newshound]

Conductor moulded onto the earth wire? WTF are you talking about

[ARW]

If they use a radial it will spoil the stereo LR experience as the current will at some point be using only one core?

Surely a final ring circuit is needed to create the perfect stereo experience that their customers require and demand.

And I can offer to install a 16A commando sockets on a final ring circuit (for a price) for any of their customers.

[Robin]

Pah! Proper audiophiles eschew AC and power everything with dead quiet DC - e.g. from Goal Zero batteries. Or perhaps now a Tesla Powerwall.

[The Natural Philosopher]

I was slightly taken aback when I plugged my electric guitar into a relatively recent guitar amp I got off ebay at silly money.

Almost no hum.

No mains transformer - its an SMPSU - and no output transformer - and sod all heatsink either - class D power amplifier. (And all the tone controls are digital...)

[williamwright]

Not so much extension leads as permanent mains flexes subject to repeated stresses at a particular point.

Bill

[newshound]

Very typical in "vase" and desk lights.

[Tim Lamb]

I'll raise that to *upright vacuum cleaner* cables.

[Dave Plowman (News]

Failure of one of the conductors in the flex to early Dysons was very common - where the flex went into the cleaner body. And anyone who maintains flexible cables of any sort knows by experience the failure is generally close to the end.

I've lost count on how many personal mic cables I've fixed where it has failed at the connector to the radio pack. And sleeving it to try and protect it simply moves the break further up the cable.

[Dave Plowman (News]

That statement is a lie. The wife's name was Karen.

[Dave Plowman (News]

I do, (radial) actually. Has its own earth too. As all decent tech mains do.

[williamwright]

It depends entirely on where the repeated stress occurs. The cable can be captive near the end.

Bill

[ajh]

I've repaired two Henry vacuum cleaners with this fault

[John Rumm]

Although fun it can be to devise ways of identifying the break position, the pragmatic and sensible answer is to replace the cable. If one core is broken, how far are the others from similar failure?

[newshound]

Except that in some cases, it's a stressed region where any of the conductors may be at risk, so cutting it short a couple of inches beyond the failure may give the whole cable a new lease of life.

My ex-wife was a vigorous ironer, and irons usually have a fairly generous cable (especially as I like to place sockets in the most convenient place for the user). Sometimes the "failure" was a worn outer, other times conductor failure at the strain relief.

[Tim+]

I reckon that 99% of the time a conductor break will occur near the strain relief. Trim both ends, job?s a good ?un. ;-)

Tim

[John Rumm]

Yup, the devil is in the detail. On things like irons and vacuum cleaners, then there are typical high stress flex points.

However on a general purpose extension lead failures of that kind are less typical.

I remember once when I was in my mid teens being sat in the room where my mother was ironing something. All of a sudden there was a bang and a flash followed by a scream! Turns out the flex had finally abraded through where it rubbed over the edge of the ironing board, and shorted. Fortunately the scream was just are result of the surprise and not actually an injury!

[Thomas Prufer]

Mains drills/drivers, flex figure-eight wrapped around handle and body to tidy it to toss in the van. Conductor breaks where the flex enters the body, inside the strain relief.

I'd chop off a foot, reusing the cable until it became too short. Had that so often that I wouldn't always test if that were actually the fault. It wasn't, sometimes it broke at the plug, and more rarely brushes or switch.

An assortment of generic strain relief rubber things comes in handy, though they generally don't fit as well as original parts.

Thomas Prufer

[Ian Jackson]

To ensure that the batteries can have absolutely no possibility whatsoever of being contaminated by residual traces of the AC mains that was used to feed the charger, surely they must always be charged by pure unadulterated DC - for example, directly from solar cells?

[Robin]

Yes! But even better to charge the batteries from other batteries charged from solar panels.

I say that because you can't count on the solar cells giving a quiet supply. There's the risk of clouds (often not visible) causing audio frequency variations. You could minimise that by shipping your batteries to a suitable location - e.g. the Atacama Desert or the Mauna Kea observatory. Even then there remains the risk of contamination by audio frequency solar variations - an area which seems still be to be poorly researched.