See the formalised forum notice: Tampering with Mains Power.

There is a problem with your policy statement which need addressing. You seem to presume that plug fuses are compulsory, well they are not as it depends on the regs. 1/ it is still legal to have a house rewired or kept to BS546 which was the UK pre-war standard and I would thoroughly recommend anyone to do it. If it is an original installation it should be renewed and the products are still available to buy to do it. Not a fuse in sight!!. 2/ to convert your house to a radial EU standard using Schuko is completely legal and I would recommend it to people who can't go BS546. 3/ if you have installed a radial system in your house or just one dedicated to your hi-fi then there would be dubious legality (not had the courts set *actual* law) to bridge out fuses from your 13 amp plugs as the required safety aspect to them is removed.

The reason for this is the law / safety rules ONLY apply to a ring mains system, it is only a ring mains system that even needs them, though even that is dubious with modern RCBs.

You also seem to think that equipment case fuses are compulsory. As I linked to you before only products built to Class I appliance regs require a case fuse. Product built to Class II appliance double insulated regs do not, and because the actual case fuse holder is only single insulated in itself it makes the fitting of the fuse illegal.

As  have said a few times on this forum "a little knowledge is a dangerous thing". So if you are going to set rules then you need to know what the *ACTUAL* rules are.

EDIT - you also presume that all electricians are actually competent. Well a majority of the ones I have met are not. Some new installations in modern built cardboard (wood frame) houses look as if they have been installed by blind Gorillas. If you search around you can find competent ones who aren't as thick as two bricks and are not just in it to create a cheap botch and try to make as much money as possible, but they are rare.

Ring mains and timber framed houses are a disaster waiting to happen, again read the article I linked to on ring mains. Fault conditions can stay active on ring mains for years until the cable finally flares and your house gets burnt down. Talk to the fire brigade about it and how many they have to go out to!!!!!!

Pinkie

certainly not in defense of mr d here, it is the current which is killer not so much as the voltage. that said lightning has a theoretical maximum of  100 million volts (this depends on length of strike, cloud formations, time of year and time of day) with a current potential of 30K amps should keep Krell owners happy for a while

Speaking a chap who has been struck by lighting twice (different years and different circumstances, must be lucky ) I am sort of living proof of luck and possibly rubber soled shoes work!!!!!

I know a gent that was sadly killed (in my youth) by the old Post Office telephone system 24V I believe?.

The voltage (electro motive force) is the push. If you take the US voltage which is half ours here in the UK the current rates for their equipment is much higher. As half the voltage roughly equates double the current, just have a look on the back of any imported equipment at the fuse rating compared to a UK spec'd model.

Which is why a lot fo CE testing is based around the LVD (low voltage directive) below 50Vac.

However the serious point under no circumstances should you attempt to 'just fiddle' with 240Vac, always consult a qualified electrician at all times and remeber you will need that certificate of compliance / installation to show any interested parties.
If god forbid you have a fire, then any 'extra' electrical work that is not covered by the approved install will nullify your insurance.

Always use qualified electrican, even if they give very strange looks when you ask them to install 6mm T&E for the ring main!

Martin

The praised Muppet experiment did not test what it purports to - again due to ohms law.  The RCBO is 2 devices in one.  An RCD which detects a short between power carrying rails and earth of a small current, and a current dependant circuit breaker which trips above a threshold current (5 or 13 amps usually).

By using a dead short the Muppet created a current in the secondary of 120A (lets assume 1 ohm instead of zero for his bit of wire, cos it makes the sums easier).  This will have allowed a current of 120A to flow in the primary, and this blew the RCBO.  It blew the fuse the high amperage fuse, it didn't blow the low amperage rcd.  But the trips are indistinguishable.  So he demonstrated that an RCBO will protect a short in the secondary which generates a current in the primary above the "O" threshold (I assume 13 amps). I should at this stage note my appreciation for a willingness to explain and demonstrate a point rather than resort to insults, but it was unfortunately the wrong test.

A 1Kohm short on the secondary - more equivalent to a human electrocution, would cause a current in the secondary of 120/1000 = 0.12amps and would not blow the "O" fuse.  So in this case, the only way an RCBO is going to trip and protect an electrocution on the secondary, is if it causes an unequal current in the 2 power rails, where the difference exceeds the trip threshold.  However, a current in the secondary is just a current as far as the primary is concerned.  It will cause the same current to flow in the primary if the secondary current is flowing from a power rail to earth, as it will if the current is flowing from one power rail to the other.  There will be an induced current in the primary, but it will be the same on both power rails, and its value at ).12 amps is way below the "fuse" or "O" threshold on the RCBO.

So the victim will not be protected.  That's how those isolating transformers for PAC testing work.

Stay safe - please! 

In fact 47K will do it !

This thread should be deleted, it is full of dangerous inaccuracies I'm afraid.

BTW the saying of proper old engineers it that "it's volts that jolts and mill's that kills"

Dave

Balancing and regen seem to go hand in hand in discussions. There is a good reason for that, some people see them in competition and some see them as complimentary.

This has only gone off on a balance trip as the discussion went silly on safety. Yes yes I know safety is important but in this case a load of nonsense was spouted for effect or some other reason I know not. You could just as easily argue safety aspects with regen but I wont as it is withing the bounds of any electrical mains operated gear as it is with balanced.

We have reached the point we really don't need to focus so much on it as modern consumer units are so fast and so certain to do their job they really take over the safety aspects.

The REAL danger we should all worry about is a loose wire in your ring on a socket and it makes the full current of the ring go up one leg and there is no fail safe to spot this as total current doesn't exceed spec, and the wire overheats, eventually flames, and you have a fire in a wall cavity. It is an INHERENT danger with rings and there has even been a campaign to try and increase government awareness to the danger.

In different flats and houses I have moved into over time one of the first things I do is go around all the wall sockets checking and tightening connections. The amount of loose ones I have found that seem to have been that way since installation is frightening.

I recently had a PIR short for Periodic Inspection Report, this was required by Building Control after a lot of work. It highlighted that one water pipe was not earthed, this was rectified immediately. The guy did say it was remarkable because so many houses fail on so many things !

Dave

Do you have to be a moderator to be allowed to make jokes?