Understanding power

Posted by: AussieSteve on 27 August 2016

I am trying to get my head around 240V power, the basics of how it works. I have been looking online but can't seem to find an explanation that I get. Obviously I DO NOT intend to work with it, just understand it. So far, 240V comes off the pole to my meter then? It then "collects" on a bus bar and distributes  to each fuse or RCD and on to the ring for lights, another for outlets, and individually for hifi ect. Power cycles back and forth? 60 times a second, and for each distribution circuit the current that is not used is returned back into the power pole?, The ground is for leakage? which can flow safely into the ground and away from harm's way. If that is basically correct, I think I understand why a dedicated spur is installed, so as to provide plenty of potential current for hifi without being sucked away into wall sockets or lights which lowers the amount of available power AND can introduce noise into that line from the blender running in the kitchen. If that is ok so far, Why is the earth so important on the hifi line as such. I imagine appliances leaking because of cheaper parts ect, but not sure. Aside from safety of electrocution with the errant current "charging" any metal or conductive thing,  isn't our hifi built well enough to not leak power back into the ground line? I have been reading some web pages about this stuff but I can't paint a visual picture to get it. The bus bars in my fuse box can't be seen, there is a piece of chipboard which has the fuses & RCD's  (fuse box) on it, so maybe the bus bar is underneath. I am assuming a "busbar" is a rectangle piece of copper like a small ruler? I have been advised to ensure I have a big 6mm line from the box and down into the ground near the box for a solid earth. I try to think of it all like a water pipe system where the main pipe comes to the distribution box, then pipes branches out into each line/s and they then have a return line on each branch. That makes sense, as such the earth in such a circuit "catches" the water and pipes the leaks away and gets rid of them for safety into the ground. As you can see, I'd be an electricians lunch boy by what I know       Any help greatly appreciated.

Posted on: 27 August 2016 by AussieSteve

I forgot to mention, why is it recommended to use say a 30 amp/240V electrical cable when I (think) I added up the total watts used in my system at full power and it amounted to around 6 amps? If the NAP250 can produce 400VA at most and be the most powerful, is 30amp cable over the top especially if on a dedicated spur. Again Thanks, and again I seek advice ONLY FOR EDUCATION NOT TO WORK ON.

Posted on: 27 August 2016 by Mattnbarns

There are far more qualified people than me to answer this but to use your analogy.

Voltage is water pressure, current is water flow.  The electrical circuit is the piping with resistance being a restriction in the pipe.  The circuit is made up from the positive a negative terminals on the plug and the earth is the overflow pipe where the current goes when there is a problem in the system.

its not how it works but a reasonable way of visualising things.

 

 

Posted on: 28 August 2016 by hafler3o

In AC systems, think of current flowing like someone filing a piece of metal. The current goes back and forth like the file over the job (analogy, say a lightbulb filament generating heat and light). At the end of a day's work the file has gone nowhere, nor has any current, it just moves up and down the wire.

30 Amp cable is over the top. Dedicated cabling for hifi (no nearby loads of any kind) and very good termination (AC wiring physically vibrates!) will eliminate detrimental effects. Just use a decent cross-section cable which is already well overspecified for hifi. A 3kW heater is far more powerful than any Naim amp!

Posted on: 04 September 2016 by Ebor

Domestic Earth connections exist to prevent wiring faults in an appliance causing electrocution to users. If no faults occur, there should never be any current 'leaking' through the Earth wire, as the OP has suggested. Here's a summary of my (very much not an electrician's) understanding:

Any electrical appliance in the UK (but I believe the set up is largely equivalent in other similar countries) which has any exposed metal that a user could conceivably touch must have an Earth wire. Inside the appliance, the Earth wire is connected to the metal (part of the) case. If you trace the wire's connections from that point, it will eventually end in a piece of metal buried in the ground - copper water pipes used to be a common way of doing this, but this is rarer - or possibly illegal in some places - now.

If an internal live wire in an appliance works loose (often as a result of many years' use) and touches the metal outer case, anyone touching the case whilst Earthed (e.g. by standing on the ground as most of us tend to do)would be electrocuted. Earth wires prevent this by providing an alternative conducting path to Earth through a nice copper wire which will probably have a significantly lower resistance than said person. The live current therefore flows to Earth through the Earth wire rather than through the person, thus meaning they don't get electrocuted. In UK-style plugs, this large Live current causes the plug's internal fuse to melt, which prevents further problems.

As for what this has to do with hi-fi, one school of thought might say that, as long as all local wiring regulations are met, then there should be no need from a sonic point of view to give one's system's Earth wires a second thought. Others claim that all sorts of modifications or improvements - carried out within local wiring regulations, of course - can raise performance. A certain supplier of hi-fi cabling based in Cumbria has some extensive suggestions on possibilities, for example, but I daresay we'd be ill-advised to try discussing them here.

Mark

Posted on: 06 September 2016 by Sounsfaber

Hi Steve, bus bar is for the earth connection only. Your board with earths onto the big bus bar, then from that bus bar goes the big earth wire that is smacked into the ground/earth outside .

The U.K.  Electrical set up is quite different than down under.  For a start They don't even have piggybacked plugs over there.  The plugs they do have are fused. Our setup is way conducive to Great audio sound.

The larger the earth wire off the bus bar, the lest resistance the better the end result. Naim say in the older manuals (nac52/preamps) that a 30/45 amp fuse set up gives the best results.naim also state  Power conditioners downgrade the quality of the naim sound.

The earth spur cuts down the back ground noise way down, which Inturn gives  transparency in spades. Makes it deeper faster and cleaner...really.  and way more pRat,

its crazy but true. Just got to trust it,  massive results minimum cost.

hope the DR.'s have gripped these big woofers of yours.