vacuum_tubes
pfm Member
Another thread that highlights why any discussion of altering or messing with mains electricity should be banned in the AUP.
Nah you dont get it, there's a witchhunt going on here for something that isn't happening.An RCCB only protects what comes AFTER it, not the input supply to it, which is coming down your unprotected cable!
Another thread that highlights why any discussion of altering or messing with mains electricity should be banned in the AUP.
Jeez.
To re-iterate things long-posted by several people, many times here before:
..because the UK uses 240Vac mains, and a Class B 32A breaker on the ring.
You can, actually - you bloody-should - look-up the time: fault current curves for breakers...
So: a typical class B breaker doesn't get out of bed below 2 x overload for ~60s, so now you have potential 64A - likely rather more - as a sustained, prospective-fault-current, and that through some cheapo flex cable - is >> 24Kw, or if you like >32+HP dissipated as heat in a 'flex' - and that means fire , right-damn-quick.
Christ.
I don't think that's true, at all.Another thread that highlights why any discussion of altering or messing with mains electricity should be banned in the AUP.
You really, really, have not thought this through. Nor all the possible fault conditions.Who mentioned cheapo flex cable Martin? You guys need to find out what is actually happening before you conduct these witch hunts. If 30ma leaks from live to neutral the RCCB in the box will trip out. Nowhere is 64 amps going through cheapo mains flex cable.
Jeez.
To re-iterate things long-posted by several people, many times here before:
..because the UK uses 240Vac mains, and a Class B 32A breaker on the ring.
You can, actually - you bloody-should - look-up the time: fault current curves for breakers...
So: a typical class B breaker doesn't get out of bed below 2 x overload for ~60s, so now you have potential 64A - likely rather more - as a sustained, prospective-fault-current, and that through some cheapo flex cable - is >> 24Kw, or if you like >32+HP dissipated as heat in a 'flex' - and that means fire , right-damn-quick.
Christ.
So now you're calling me an idiot and you still haven't asked what is actually happening.I dont; think that's true, at all.
There's a duty of care to protect people from idiocy. and that means - not necessarily , the idiot.
I don't think that's true, at all.
There's a duty of care to protect people from idiocy; and that means - not necessarily , the idiot.
J.C. Maxwell & O. Heaviside readily disagree...
Not sure what that has to do with it. I just added a direct earth line with lower resistance that isn't polluted by the other stuff in my house,
I wish @Robert still had his photos up of his makeshift hi-fi mains lead running off the pants press down the hall, via an electric drill on full tilt along the way, plus a few other odds and sods (toaster? microwave oven? drinks blender?). Think he did a couple of with/without recordings. This, from back before the internet police (i.e. Google ads) decided that they should be the ultimate arbitrator when it comes to who's IP should be allowed to be shared online.Here’s an easy experiment for people to try if they don’t think mains cables can make a difference…
Make things deliberately “bad“ by plugging one item of your hi-fi in via a long extension reel into a distant mains socket. Can you hear any difference?
(Hint: while you’re at it, measure the AC voltage difference between the Earth of the extension and the Earth of your usual wall socket)
I imagine your sub <1ohm requirements were backed up by application of the official “lick” test and recorded for officialdom...last time 'we' (project team) had a sub -1 ohm local earth impedance mat requirement* - it also took >100m of driven, 100mm casing - and that in 'good' wet clay soils in S Bristol.
A simple 'earth spike' is for the birds; 4-6ft of driven spike is going to be c 100ohms , at very best, in conducive soils in UK. No doubt @Somafunk can speak to much more detail there!
[* for the HV:LV substation; the permanent V20, quad-turbo 2.5MW backup up genny that was, &remains! also grid-tied as part of that project - sounded bloody amazing on full-load test; exceeded spec too: 0 to full output on test, <10s!]
^ it was all about the new 11Kv HV : LV 2MVA transformer on site
Lick- it ? - No thanks, too fizzy for me
But might stop your installation killing you, your family, and everyone else in your substation supply if you are TNC and a supply neutral fault develops and your new earth becomes the neutral line for the whole postcode.Probably like other houses. Bonding the new earth to mains would defeat the point.