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Don't let anyone tell you mains supply doesn't matter

While PME systems generally have a very low earth resistance (<1 Ohm), TT systems with a single earth rod are likely to be much higher resistance (say 15 Ohm) and so additional earth spike networks could really make a difference and bring this figure down as Marco has found.

I do wonder about the impedance of these earthing systems to noise signals on the 0v/earth line at audio and higher frequencies as this could impact system sound quality especially on source equipment where the signal voltages are lower. My guess is that standard twin and earth cables (which use a smaller cross section conductor for the protective earth vs the L and N conductors) will not offer the best low impedance route to earth for audio and higher frequency noise signals.

Certainly Twin and Earth cable isn’t designed to have low impedance at high frequencies - whereas lightning conductors (flat strip) are. I’m wondering if an earthing cable and spike network designed for higher frequencies using copper strip, conductive concrete etc would make a noticeable difference. Obviously this would need to be bonded and meet the regs.

I’ve also wondered about using thick coax (WT125) to connect a 0v line to a stainless steel earth plate lowered into my well - probably much cheaper than a load of earth grounding boxes!

Has anyone done any measurement or analysis of noise voltages on earth conductors that might save me the effort of actually getting the digger out and installing some of these?

Thanks Bill
 
Fair enough, and all valid points. As an agnostic though, who openly admits to having 'shite hearing', you do seem rather keen to push the validity of blind-testing for evaluating certain aspects of audio, which given your position, shouldn't really be of much interest.

It's not so much 'pushing' blind-testing as saying it's the only way to prove you can hear a difference, particularly one which, theoretically, should not exist (unless you can think of another way). Of course, if you don't want or need to prove anything, fair play, fill yer boots.
 
The plug fuse is in place to protect the cable from the plug to the appliance, which is normally protected by its own internal fuse. If the rating of the mcb or rcbo at the Consumer Unit is lower than the current capacity of the in wall wiring and the cable to the appliance, then there is no need for further fuses.

If you remember the old round pin plugs, you’ll also remember that they didn’t include plug fuses. Ring circuits are basically the reason for plug fuses, with the ring rated at 32A and the plug to appliance leads generally rated at 13A or less.

Hi Bill,

Thanks for that, which mostly makes perfect sense.

Yes, I've used un-fused round-pin 15A plugs before, which are excellent. Not just because of the lack of any fuse, but IMO their overall build quality is superior, as well as the tightness of the connection/fit offered with their partnering sockets, which is always more solid, compared with that of their (fused) 13A counterparts and sockets.

However, the bit in bold above is what I'm struggling to grasp.. Are you saying that the ability for the plug fuse to protect *the cable* (for the moment, let's ignore everything else) is negated by the protection offered at the CU, if the current capacity of the overall set up allows?

Essentially, *exactly what* is protecting the cable itself, in the absence of a plug fuse, and how? Thanks!

Marco.
 
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I did? I don't recall discussing earth rods, let alone suggesting how to connect one, Ian. Is it my memory or your embellished and/or imaginary take on sth I've said?

Here you go Mike,

As I've got a combination of 10 and 6 mm2 T & E, as do friends of mine, I really think that's all you need. The earth core is more than adequate, and if you're on TT, you'll be able to add a spike to the hifi end if you can be bothered. Far better to have multiple radials (even 6mm2 if routing is a prob.) in a multiple ganged c.u., pref. with RCBOs. One big cable split into hydras, double sockets etc. is undoing what you're trying to achieve, in effect. I have one radial per piece of kit (and/or a spare). Also more convenient for isolating kit separately for that odd occasion.

&

Bit technical for me, but basically, adding a TT earth to a PME system is optional and dependent upon the installer's analysis. I would guess that adding a TT might be the norm, though. This is my understanding from scanning the article. The 'multiple' bit presumable refers to the multiplicity of earth bondings en route to the grid (not just the one) and not to whether a TT has been added.
 
Ye gods; when did I write that and is it verbatim? The second para. seems to refute the first if so. I cannot believe I suggested adding a spike to a PME earthing system as I've known that to be a no-no for yonks. However, it seems I was responding to an article and questioning my understanding of it rather than offering advice. Wonder how long ago that was.

I don't understand the practical difference between connecting an earth spike at the c.u. end or at the other end, this which was mentioned regarding Marco's installation. Is there a difference in the reduction of impedance between one end or the other, as they're all connected? (Must say, I'm not sure where mine was connected). On a different scenario, if the c.u. is brought into the hifi room via a tail (as some have done), where would that earthing rod be connected?
 
As far as I know any landlords registered with council require gas and electrical safety certificates to be checked yearly.

As a landlord, I can shed light on this. Whereas the Gas Safe inspection (and service), previously known as a CP12, is an annual necessity on all gas appliances, an annual electrical check is not (currently) a requirement. However, within a matter of months, ALL rented properties are required to have had an inspection and update, valid for 5 years, if necessary. This would, I believe, include PAT tests on extensions/etc but not sure about that one.

I've had two major overhauls within the last year; costly but sensible that the gov. has brought electricity into line with gas.
 
Thanks for that, I assume my landlord had a sparky to check setup as was bit surprised at how much system has grown.
When I was landlord in Portsmouth the council were complete pain, regs were stiff as I was letting to university and housing benefit tenants, they checked earthing and every plug socket in a seven bed property. Wiring had to be certificated as part of integral fire detectors and emergency lighting.
 
Essentially, *exactly what* is protecting the cable itself,

The way I see it, Marco, is that you may be conflating a radial system (which you have) with a ring main. As Bill said, the 13 A fuse in the plug is to protect the mains lead (a.k.a. flex) because the ring is (I think) protected overall by a 32A breaker. With a radial, that is in itself protected by its own breaker (MCB/RCBO) which would reflect the amperage capacity of the mains lead and cable rating; i.e., doing the same job as the 13A fuse.

It's interesting that Bill states that 'there's no need for further fuses' providing the MCB rating is below that of the radial and appliance lead. This in essence is what I feel, partly from a logical standpoint but also because of other similar installations as aforementioned, but I've been having trouble getting acknowledgement prior to Bill's post above.
 
hey checked earthing and every plug socket in a seven bed property. Wiring had to be certificated as part of integral fire detectors and emergency lighting.

Probably because it was an H.M.O. (house of multiple occupation), where rules on most things (fire doors etc.) have been draconian for a number of years now.
 
It's not so much 'pushing' blind-testing as saying it's the only way to prove you can hear a difference, particularly one which, theoretically, should not exist (unless you can think of another way). Of course, if you don't want or need to prove anything, fair play, fill yer boots.

Sure... However, blind testing can only be regarded as the only way to prove you can hear a difference, if you don't consider such testing as flawed, both in relation to what's being tested for [does the nature of the claimed phenomenon lend itself well to being blind tested?] and its arguably adverse impact on the test subject to provide a reliable answer, as indeed was outlined earlier, in terms of stress and/or the pressure of wanting to guess correctly - all of which is absent under normal (relaxed) listening conditions at home.

It's a bit like when I was at school (and I suspect that this also applied to others), in that with any given subject, my homework was always better/performed to a higher standard than when answering the same questions under exam conditions, and with it, time constraints.

When I was doing the same work at home, in a relaxed/stress-free environment, with no pressure or constraints on my time, I always produced better work and results - and it's a bit like that with hi-fi and successfully attempting to hear differences under blind conditions, where there's pressure on you to prove you can hear them, compared with at home where such things (if they exist) are revealed more naturally [and unforced], often over time.

In that respect, I'd contend that differences heard under the latter conditions are (arguably) just as real as those supposedly 'proved' with blind testing.

However, I care little about proving anything to anyone, although if possible it's always nice to do so, but my main interest on forums is in being able to relate my valid subjective experiences to anyone who may be interested, without some 'technical person' rather aggressively and rudely insisting that I have to prove them to him, in order for them to be considered as real, when instead it should simply be up to those reading to judge that for themselves, and whether or not they believe what I'm saying or consider it as plausible.

If hi-fi forums are successfully to be places where enthusiasts (which let's face it, the vast majority of whom are subjectivists) can discuss their experiences freely, with a view to perhaps helping others, then a platform must be created which allows them to do that, without fear of ridicule, otherwise it simply stifles possible learning, by discouraging those who may have had something useful or interesting to say, simply because it doesn't fit with someone else's (rather narrow-minded and inflexible) scientific belief system.

Yes, certain claims need to be challenged, but challenged politely and respectfully (and with an open mind), with a view to ascertaining whether or not said claims have some basis in truth, not rudely and automatically dismissed as 'nonsense', simply because some folks dislike what's being claimed, as they consider it an affront to their scientific teaching and/or they find it uncomfortable because it challenges their rigidly, long-held beliefs [cognitive dissonance] - and that applies to both objectivists and subjectivists!

Otherwise, the exercise is pointless, simply results in conflict, endlessly circular arguments/binned threads when fights break out between both camps, and nothing new is ever learned.

Marco.
 
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Is the discussion to compare the solutions of those that indulge this end of hifi, it seems this as with most conversations on hifi peripherals is taken over by those saying prove it? Valid but not the only answer.
 
... Essentially, *exactly what* is protecting the cable itself, in the absence of a plug fuse, and how? Thanks!

Marco.

Hi Marco

The current protection at the Consumer Unit limits the current flowing in the whole of the downstream circuit connected to it - so if the max current allowed by a CU MCB or RCBO is say 6A, then this is the max current that can flow to the appliance(s) on this circuit. So if the appliance cable is rated to carry at least 6A then no further fusing is required as the circuit will not be ‘allowed’ to carry more than 6A (assuming the MCB or RCBO works). If the appliance cable is rated at 2A, then further fusing would be needed.

I guess in the days before ring circuits, appliance leads were sized appropriately for the rating of the radial they were connected to (eg 15A, 5A, or I think 2A).

It is quite normal these days to use unfused round pin 5A plugs on lighting circuits, due to the protection provided to the lighting circuit at the CU.

Cheers Bill
 
Ye gods; when did I write that and is it verbatim? The second para. seems to refute the first if so. I cannot believe I suggested adding a spike to a PME earthing system as I've known that to be a no-no for yonks. However, it seems I was responding to an article and questioning my understanding of it rather than offering advice. Wonder how long ago that was.

It is verbatim mike.

I don't understand the practical difference between connecting an earth spike at the c.u. end or at the other end, this which was mentioned regarding Marco's installation. Is there a difference in the reduction of impedance between one end or the other, as they're all connected? (Must say, I'm not sure where mine was connected). On a different scenario, if the c.u. is brought into the hifi room via a tail (as some have done), where would that earthing rod be connected?

The issue is covered within the regs, by not connecting both rods to the same point at the MET or within a consumer unit you are creating two different equipotential zones, therefore during certain fault conditions current can flow between them. The cable used for connection of an earth rod should be a minimum of 10mm, however this is calculated using the adiabatic equation, (calculating the resistance of the cable and the potential fault current possible, so ensuring the cable will not melt or vaporise)
If you have a fabulously low impedance to earth you would have to use a larger cross sectional cable to ensure it could carry the fault current for long enough to operate the fuse or MCB etc.







Here you go Mike,

]
 
The way I see it, Marco, is that you may be conflating a radial system (which you have) with a ring main. As Bill said, the 13 A fuse in the plug is to protect the mains lead (a.k.a. flex) because the ring is (I think) protected overall by a 32A breaker. With a radial, that is in itself protected by its own breaker (MCB/RCBO) which would reflect the amperage capacity of the mains lead and cable rating; i.e., doing the same job as the 13A fuse.

It's interesting that Bill states that 'there's no need for further fuses' providing the MCB rating is below that of the radial and appliance lead. This in essence is what I feel, partly from a logical standpoint but also because of other similar installations as aforementioned, but I've been having trouble getting acknowledgement prior to Bill's post above.

The trouble comes because with a lighting circuit you are limited by what you can actually connect, a 100w lamp perhaps ? With an unfused radial connected like Mike has or even a 15a round pin plug it would be possible to connect a connector block and with a plethora of high power amplification overload the connecting flex without tripping the circuit protecting device. Unlikely I know, but still possible.
But at least you could pull the plug in case of any problems, rather than attempting to yank the captive leads from the back of your equipment!
 
Hi Marco

The current protection at the Consumer Unit limits the current flowing in the whole of the downstream circuit connected to it - so if the max current allowed by a CU MCB or RCBO is say 6A, then this is the max current that can flow to the appliance(s) on this circuit. So if the appliance cable is rated to carry at least 6A then no further fusing is required as the circuit will not be ‘allowed’ to carry more than 6A (assuming the MCB or RCBO works). If the appliance cable is rated at 2A, then further fusing would be needed.

I guess in the days before ring circuits, appliance leads were sized appropriately for the rating of the radial they were connected to (eg 15A, 5A, or I think 2A).

It is quite normal these days to use unfused round pin 5A plugs on lighting circuits, due to the protection provided to the lighting circuit at the CU.

Hi Bill,

Thanks for that. All is clear now!:)

Marco.
 
The issue is covered within the reg's. By not connecting both rods to the same point at the...MET... or within a consumer unit you are creating two different equipotential zones; therefore, during certain fault conditions current can flow between them.

Thanks Ian; I'm not conversant with earthing rod criteria (except the TT/PME caveats) but I think I understand from your text the problem potentially arising from 2 separate earthing connections. Took me a couple of readings etc. though. What is MET an abbreviation for?

Can you please tell me where you got the supposed quotes of mine from? I'm scratching my head, because I vaguely remember getting explanations (via a link?) to my questions relating to TT and PME earthing and you might well have been the chap who advised me. If so, it must have been a long time ago and I give you credit for superb forum post archaeology. :)

With an unfused radial connected like Mike has or even a 15a round pin plug it would be possible to connect a .........

Unfused? I have 1 radial per piece of kit, fused by its own RCBO. Each cable is either 6 or 10mm2, which I admit, is unnecessarily o.t.t. but what the hell? Your potentially dangerous synopsis of adding to these circuits would not apply. For others with fewer radials which are then split into 'spurs', this could well be pertinent.

But at least you could pull the plug in case of any problems, rather than attempting to yank the captive leads from the back of your equipment!

It's about as quick for me to access my c.u. as disconnect IECs; besides, the RCBOs would handle fault conditions, I'm led to believe, obviating the need to rush anywhere. ;) I've just thought that, in your latter (captive lead) scenario, would not disconnecting the fuses (simple half turn) have the same effect? Not sure about this, but seems feasible.
 
Hi Bill,

I meant to get to this yesterday, but didn't have time...

While PME systems generally have a very low earth resistance (<1 Ohm), TT systems with a single earth rod are likely to be much higher resistance (say 15 Ohm) and so additional earth spike networks could really make a difference and bring this figure down as Marco has found.

So are you saying then that with 'TT systems', in an old property such as mine, it's feasible to be able to significantly reduce the impedance of the house earth, with the use of additional rods, such as I've done, and if that's the case, then why shouldn't it be audible?

Others and I certainly heard the difference, that's for sure! And not only with my installation, but in other systems where the same work was carried out in similar properties.. Therefore, just as the reduction in impedance wasn't 'imagined', but indeed measured on an appropriate testing device, I'd also contend that neither were the subsequent sonic improvements!;)

I do wonder about the impedance of these earthing systems to noise signals on the 0v/earth line at audio and higher frequencies as this could impact system sound quality especially on source equipment where the signal voltages are lower. My guess is that standard twin and earth cables (which use a smaller cross section conductor for the protective earth vs the L and N conductors) will not offer the best low impedance route to earth for audio and higher frequency noise signals.

An interesting observation. Perhaps that's why I heard a notable improvement in SQ when I moved from using standard twin and earth in my mains set-up to this stuff instead: https://www.tlc-direct.co.uk/Produc...MI6OG75MfV8AIVToFQBh3y3AzNEAQYBiABEgLb9PD_BwE

Bloody nightmare trying to get it into sockets, though!:eek::D

But it definitely made the system sound better, especially in the areas you mention!

I’m wondering if an earthing cable and spike network designed for higher frequencies using copper strip, conductive concrete etc would make a noticeable difference. Obviously this would need to be bonded and meet the regs.

Based on my experience, I'd certainly say so. Conductive concrete, I used this stuff (if you have time to read through it, there is some very interesting info here on all aspects of earthing and how this material improves and streamlines the whole process): http://earthingservices.com/conducrete/) is very effective and for me the way to go, if want to go the job right and make it last a lifetime.

So if you do go ahead with your intended project, please document it here and post your findings, as it's this sort of stuff we need to see far more of on forums!:cool:

Marco.
 
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However, within a matter of months, ALL rented properties are required to have had an inspection and update, valid for 5 years, if necessary. This would, I believe, include PAT tests on extensions/etc but not sure about that one.

It does not include any appliances,extension leads, anything plugged-in etc- just a (cover-open) review of Consumer unit (and breakers and internal wiring ) and fixed wiring (CU, earth loop impedance checks at key points - e.g cooker outlet and shower and say one on each ring - and physical condition of all outlets and controls.
 
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Dear me, Jez. Your skills are well acknowledged on here, along with your ability to offer sound (!) and helpful advice, but you do yourself a disservice by standing on your high-impedance soap-box and ranting against those who have a very valid, albeit more subjective take on this arcane subject of sound quality influenced by that premier source, the electricity supply. Unfortunately, your accusations of arrogance in others is tantamount to being a reflection you cannot see. 'Umbly yours.

I couldn't disagree more strongly. Your beliefs are as valid as those of a Qanon follower or anti-vaxxer and 100% wrong! Mains, fuses. power cables etc etc is entirely fake news... those who believe in such crap are no better than those who believe in David Ickes rantings.

Belief in such things ("belief" as in religious faith for it has no factual content) is in fact as good an example of Dunning-Kruger Effect as one will ever see as thinking such things are possible proves you have no understanding of the subject whatsoever.

Have a good think about what you and several others are saying here. You admit no knowledge of electronics, that you have to send away any faulty equipment to someone like myself to be repaired. You certainly couldn't design anything, not even a crystal set radio, and wouldn't in fact have the knowledge to visualise the schematic of a crystal set in order to know why I used that example. And yet... you reckon that on something as simple as mere lengths of wire, page 1, chapter 1 of "My first book of electricity" "Conductors and Insulators"... you are right and I and all the electronic engineers in the world are wrong and you are right???? REALLY? I mean REALLLLLYYYYY???????
 


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