There is a limit, one spur per socket if unfused. Each spur can only have one socket or appliance if unfused. If fused, do what you like within 13A, apparently.
Don't let anyone tell you mains supply doesn't matter
- Thread starter kjb
- Start date
Unfortunately most audiophiles have very little actual understanding of their electrical installation, so here goes:
When designing an electrical circuit we take into account several factors, overall current requirement, length of the electrical circuit ( this is more critical in radial circuits), where the cable has to run, so if within 100mm glass fibre insulation it requires a 50% de rating, does it run externally, does it go through a special zone (a bath room).
How many other cables is it running alongside.
It used to be, due to the cost of cable, the ease of installation and potential current requirements that rings were used as two runs of 2.5 t&e can safely cope with 32 Amps as a safety margin has been built in to these calculations. Theoretically a single run could manage without overheating 27 amps but this does not allow for all the other safety factors.
The dimensions of the cable 1.5, 2.5, 4.0, 6 & 10mm will change the impedance so a 6mm radial would be expected to have a lower impedance than a ring circuit in 2.5 t&e.
When we talk about impedance we are referring to the impedance of the live and CPC ( earth) as the impedance has to be within defined limits to ensure the safe operation of the safety device be that a fuse an MCB or rcbo.
The impedance we are talking about will have no effect on any equipment connected apart from operation of the safety device, definitely not sound quality.
I am struggling to re read on my crap phone so there might be a part 2.
MUTTY1
Waste of bandwidth
That hasn’t changed then.
On getting an electrician to sign off/approve your work? Good luck with that!
I installed a mains pressure water heater onetime. They are potentially dangerous and need passing by the authorities. Unfortunately their inspector knew nothing about this type of installation so insisted I get a registered plumber to sign it off within thirty days. I approached one and got quite an earful understandably. In the end I got hold of the manufacturer who provided a tame one. Close call.
Arkless Electronics
Trade: Amp design and repairs.
Precisely!
Yes, the electrons have twice the surface area to go at, as you say. I'm not sure if a ring of 2 x 2.5mm^2 twin and earth has a different impedance to a radial of 1 x 5mm^2 T&E though. Assuming you could buy 5mm2 cable, of course.
I'm sure Russ Andrews can whip you some up.
Sue Pertwee-Tyr
Accuphase all the way down
mansr
Objectionist
Gross misinterpretation of data, possibly with intent to deceive. The mains impedance at audio frequencies is irrelevant. The power supply makes sure of that.
Spraggons Den
pfm Member
From my college electrical course in 1981, i think a cable with a surface area of 2.5mm if doubled comes out as 6mn which is very common size commercially.
Mains frequency is 50 hertz
mansr
Objectionist
Doubling a circular cross section of 2.5 mm² to 5 mm² increases the diameter from 1.8 mm to 2.5 mm.
Sue Pertwee-Tyr
Accuphase all the way down
There seems to be some connection to PFM. Perhaps Martin is/was a contributor to the DIY section here? Anybody know any more?
Sue Pertwee-Tyr
Accuphase all the way down
Yes, I know that, of course. The piece seemed to suggest that the current draw was not confined to 50Hz, but other harmonics might be in play. I don't know enough, but at a quick peruse of other pieces, the author (Martin?) seems to be consistent with what people say on here, so I'm doubtful the malign motives alluded to upthread are appropriate.
Martin's a regular on here, esp DIY and OT. The rising impedance of a typical mains supply circuit with frequency is of interest if *the load* varies cyclically at these kind of frequencies. The load does not vary in a linear fashion with music frequency, as Martin says it's complex and non linear.
Sue Pertwee-Tyr
Accuphase all the way down
But neither, presumably, is it confined to 50Hz?
mansr
Objectionist
Yes, you'll see some current at the first few harmonics. It's still easily verified by anyone with a multimeter that playing music (or high-frequency tones/noise for that matter) doesn't result in any appreciable voltage dip. Whoever the author is and whatever his intentions were, that web page is wrong.
Sue Pertwee-Tyr
Accuphase all the way down
I'd be interested in his take on mansr's comments, but don't know who to flag (is it Martin Clark, perhaps?). If you know who it is, would it be appropriate to @ him?
Not necessarily. It may be confined to 50Hz, or there may be other loads in play. It's going to be dominated by 50Hz. Is the load at higher frequencies significant for any real world loads? I doubt it. The other thing to bear in mind is how a PSU works. Step down, rectify, smooth. You are going to get a 100 pulse per second drain on the PSU that is topping up the smoothing caps in the PSU inside the box. That's 100Hz, and it happens all the time the PSU is running and delivering any current.
It is Martin Clark's article, I'll drop him a PM.
mansr
Objectionist
OK, he doesn't seem to be malicious, so it's probably just a misunderstanding.
Arkless Electronics
Trade: Amp design and repairs.
It's shameful that people who know way, way, way, WAY less than nothing at all about electricity and electronics continue to argue with professionals and even argue with the laws of physics! If I were running a forum NOTHING would be more strictly against AUP... FWIW
It is no different, other than in severity of possible outcome, to if someone was to ask medical advice off topic of one of the few consultants on pfm and then "I know nothing about medicine BUT" chancers come along and start bleating on about aromatherapy and aligning chakras being more important than the consultants diagnoses of possible cancer.
It is no different, other than in severity of possible outcome, to if someone was to ask medical advice off topic of one of the few consultants on pfm and then "I know nothing about medicine BUT" chancers come along and start bleating on about aromatherapy and aligning chakras being more important than the consultants diagnoses of possible cancer.