Another mains fuse hits the streets

[Ian G]

There appears to be a lot of confusion re rings & radials.
A ring is mearly a way of connecting a number of sockets with cable rated at a lower current carrying capacity than the upfront protective device by looping the cable back to the consumer unit. You can therefore have more sockets on the circuit.

A radial is a single cable which can either supply a single piece of equipment, shower, oven or a single or DG socket etc, this is fused accordingly for required current and the cable is likewise sized to suit,
or indeed a line of sockets, the number of sockets is dependent upon various factors, however they will all be protected by the upfront device.
2.5 T&E would be protected by a 16A device or possibly 20A for sockets for a single piece of equipment you could go to 25A.
4mm T&E could be fused for 32A for a radial.

Nowadays only the utility or kitchen would be a ring, other rooms being radials this gives you maximum discrimination against faults.

A spur is a single leg off a ring or radial and can only have one socket attached unless it is protected via a Fused Spur or Switch Fused Spur.

 

[martin clark]

Nowadays only the utility or kitchen would be a ring, other rooms being radials this gives you maximum discrimination against faults.

The drive to that has only really happened since last update to IEE regs 18th ed which is what , 2 yrs old. tho' based on the 17th version of 4-5-6yrs previous.

Almost everyone here in UK homes, interested in such, are dealing with ring mains, yet - for a long time.

 

[jimification]

I'm assuming that the selling point of these kind of fuses is that they supposedly have a less damaging effect on the electrical supply than bog standard fuses?

If that's the reason for adopting them then I could see why you might spend a fiver or a tenner on one but once you get into the hundreds wouldn't you just be better off replacing your wiring with a Shuko power block or a Hydra? Surely if it's about reducing the damage done by a fuse then the best fuse is no fuse? (still retaining one on the end of the block for safety reasons)

Or is the idea that these fuses somehow improve / filter the supply?

 

[Mr Pig]

I think it has to be some kind of magic?

 

[narabdela]

I think it has to be some kind of magic?

Aimed at people who believe in magic.

 

[tiggers]

It's total nonsense and how a bunch of relatively intelligent people (this is aimed at myself too before anyone gets bent out of shape) can discuss it for 15 pages rather than just ignoring it like we should do is worrying!

 

[John Phillips]

I think it has to be some kind of magic?

This hobby is a fascinating mix between physics, engineering and illusion.

At the physics - engineering end of that spectrum there's a lot that's very well understood and has been for a very long time.

At the engineering - illusion end of that spectrum there's more uncertainty right up to very individual, very variable personal experience.

It is no wonder to me that the industry dresses up personal illusion in the clothes of engineering and physics, to promote and sell "solutions" to a market which is not well informed about the realities of engineering and physics, and so can be persuaded to worry unnecessarily.

IMHO enjoying a personal illusion is the end goal. What I enjoy will not necessarily be what others enjoy so I don't evangelise. From my PoV justifying what I enjoy with a spurious connection to engineering and physics is not necessary and is actually destructive to those who do know that end of the spectrum but also appreciate the truth behind Arthur C. Clarke's "Any sufficiently advanced technology is indistinguishable from magic".

 

[Alex S]

It’s all smoke and mirrors, with the emphasis on smoke.

 

[paulfromcamden]

It's total nonsense and how a bunch of relatively intelligent people (this is aimed at myself too before anyone gets bent out of shape) can discuss it for 15 pages rather than just ignoring it like we should do is worrying!

It is quite funny though.

 

[paulfromcamden]

It’s all smoke and mirrors, with the emphasis on smoke.

Replacing the mirrors with smoke might help remove unwanted reflections.

 

[stevec67]

Ok, it’s a UK thing?
We don’t do that here.

As others have said it allows you to use less cable and of lighter section, and it was developed after the war when there was a shortage of materials across all of Europe. You used to be a spark, so you will know that the French radial system allows 16A per radial connection. I think that's what it was when I was there. The UK ring main allows you to run a loop of 2.5mm T&E around the house, typically one per floor and another one for the kitchen not very much cable at all for a whole house, and that's safe for 30A total. Yes, it does explain why we fit fuses to EVERYTHING.

 

[stevec67]

Out in the former colonies in SE Asia, we follow UK practice except our mains sockets are daisy chained in a room, not in a ring. Each room on a 20A MCB. Plugs are UK style fused.

The French system is like that but no fuse re at the plug. It relies on the RCCB at the consumer unit for safety. Safe enough, RCDs cut faster than a fuse and if there is any leakage to earth. A fuse system alone will allow the case to go live at low current without blowing, and this can kill you. Any system With an RCD will say "Nah. Not having that. Click. " Isn't it within 50 ms?

 

[Mike Reed]

Nowadays only the utility or kitchen would be a ring, other rooms being radials this gives you maximum discrimination against faults.

Interesting, Ian; I wonder why, though, when ring mains have been in, have been improved and have been successful for 75+ years. Personally, I just can't see any advantage from separate radials which are then split (requiring fused 13 A plugs presumably) per floor (or room?). Baffles me to what advantages this brings, and why kitchens/utterly rooms are deemed better with a ring. Any ideas?

Just thought; the lighting circuits will presumably remain as low current rings ?????

 

[chartz]

This hobby is a fascinating mix between physics, engineering and illusion.

It is no wonder to me that the industry dresses up personal illusion in the clothes of engineering and physics, to promote and sell "solutions" to a market which is not well informed about the realities of engineering and physics, and so can be persuaded to worry unnecessarily.

Exactly this. The fancy, esoteric stuff is intended for gulls that don’t have basic electric/electronic knowledge. Therefore, it is magical.

 

[Mike Reed]

I'm assuming that the selling point of these kind of fuses is that they supposedly have a less damaging effect on the electrical supply than bog standard fuses?

I'm assuming that if your supply has to negotiate a bit of crappy fuse wire in a mass-produced case, the impedance rise could be mitigated by a quality wire made out of a more conductive material, better encased with end caps made out of similarly more conductive material.

Whereas I can see this being of benefit, the common or garden 13 A plug fuse holders may prove to be a caveat. How many fishies have at some stage gone to town in cleaning all contact areas (where feasible) within their ring mains supply to hifi? I've read in forums of countless cases where results of doing this have elicited a eureka moment. Common sense, really; corrosion effectively restricts flow by increasing impedance, thereby reducing dynamics. That's the way I see it, anyway !

 

[chartz]

I've read in forums of countless cases where results of doing this have elicited a eureka moment. Common sense, really; corrosion effectively restricts flow by increasing impedance, thereby reducing dynamics.

But Mike, this doesn’t really make electrical sense. We are not dealing with sound signal here!
And don’t forget that there is a transformer into the equation.
There is no way cleaning your fuses can have any effect on what’s going on inside the electronics.
Don’t believe every nonsense that you read. Especially the silly YouTube videos (see above).

 

[Mike Reed]

It’s all smoke and mirrors, with the emphasis on smoke.

Mirrors are okay, Alex but I'd worry about the smoke aspect !

Yes, it does explain why we fit fuses to EVERYTHING.

Except cable and mains supply threads ? ?

It relies on the RCCB at the consumer unit for safety. Safe enough, RCDs cut faster than a fuse and if there is any leakage to earth.

RCCD ? Is that a new reg's change from RCBO? Surely, all domestic installations of any modernity will have RCDs on the power circuits. The mini circuit breaker is, I believe, for overload only. The RCD is distinctive in detecting an earth fault or live meeting earth or neutral as would happen if you sliced through your electric mower (who hasn't done that?????) and is effectively instantaneous as mentioned.

 

[Mike Reed]

There is no way cleaning your fuses can have any effect on what’s going on inside the electronics.

Well, I did say all accessible connections, not just fuses. I know this is irrelevant to electronics, but a few years back I had a table lamp which was erratic. Sometimes would come on, sometimes flicker, etc. I simply cleaned up the pins which were really oxidised, after checking all else. No prob's after that. I don't think the (toroidal) trannies are the be all and end all for restoring/reducing increased impedance levels cause by oxidisation etc.

Of course, I've long been an advocate of the mains supply being the prime source, despite Ivor's former protestations of his fruit box being it.

 

[Mike Reed]

Exactly this. The fancy, esoteric stuff is intended for gulls that don’t have basic electric/electronic knowledge. Therefore, it is magical.

I did mention, I think upthread, of my local dealer friend, whose qualification and career was/is in audiosonics or whatever it's called. I, like others of our bake-off group, trust his ears and judgement. He tried one of those fancy fuses (the ones mentioned by the o.p.) and was surprised that he heard an improvement, on his Supernait 3, I think. Another member maybe tried one subsequently and similarly was impressed. Expectation bias? Quite the opposite; scepticism bias more likely.

Whereas I couldn't try one even if I wanted or had sufficient interest, I wouldn't poo-poo them out of hand. Regarding these entrepreneurs who think they have a useful product and are prepared to research and market it, I'quote a more inappropriate proverb/adage; 'there's no smoke without fire'.

 

[stevec67]

Mirrors are okay, Alex but I'd worry about the smoke aspect !

Except cable and mains supply threads ? ?

RCCD ? Is that a new reg's change from RCBO? Surely, all domestic installations of any modernity will have RCDs on the power circuits. The mini circuit breaker is, I believe, for overload only. The RCD is distinctive in detecting an earth fault or live meeting earth or neutral as would happen if you sliced through your electric mower (who hasn't done that?????) and is effectively instantaneous as mentioned.

RCCB: residual current circuit breaker.
RCD: residual current device.
Typically these are one and the same thing.