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The 'fusing factor' is accomodated in the current rating tables.

Well I am not going to debate RFC in general - we would be here all week :D. Melt the cable - don't you think that is just a slight exaggeration given that the ratings are based on an ambient temperature of 30 degrees and assume that the circuit is operating at 70 degrees before overload...

Unfused splitters are not BS 1363 accessories. The problem with all of this is that if you make a regulation unnecessarily proscriptive because of what someone might do, you end up reducing the potential benefits to all. This particular example is not a good one as it is difficult to see...

BS 1363 Socket outlets are intended to be used with fused plugs - they are not intended to be used without them - that would be a misuse and there is no requirement to protect against it.

There is no requirement to accomodate the misuse of BS 1363 accessories - read 120.1 - last three words.

Am I missing something here - why are you applying 433.2.2 (ii) to a final circuit for a socket outlet? Clause (ii) to regulation is as old as the hills and it was designed to allow the connection of small fuse units to large bus-bar systems. A typical example would be a 15A BS 3036 MEM one...

It would appear that you misunderstand the purpose of BS 7671 – Requirements for Electrical Installations. This is a British Standard that addresses the design, erection and verification of electrical installations. It is not an instruction manual for electricians - the last set of regulations...

The figures probably originate from research conducted by the Electrical Research Assocation (now ERA Technology Limited). The work was commissioned by the IEE.

Eric What others may do at some future time is not your responsibility. It is for them to decide what, if any, modifications can be made to an existing installation - see [131.8]. There are a good reasons for this - you cannot foresee future changes and labelling installations because you...

I don't know about that - you see Legrand now own Tenby. BS 951 was probably largely written by Tenby way back in the day. However, we now have a new version of BS 951 : 2009 and the Legrand clamp 'comforms to it' - now I wonder who made sure that happened :D.

Ericmark's link points to an article about the way they work. It is basically as you have said, but you cannot assume that the system would be 'earth free'. This may be true on small units, but it is unlikely, and indeed undesirable, on large systems feeding a number of outlets. Much of the...

I doubt that the 16th edition actually 'required' it. Like the 17th it just just alluded to it by the fact that the BS EN 61009 devices were included in 41B (now 41.3). It is a problem that only really affects countries with high earth fault levels (mainly northern Europe, north America...

I agree the terminology active and passive is poor. I am using active to describe RCDs with an active element i.e. the difference amplifier. I am using passive for those RCDs that still use a precision relay. The former requires a supply for the amplifier, and the latter does not as the...

Without wishing to get involved with the 'are they good or not' debate - it might be worth pointing out that down lighters can be fitted with spot lamps (beam angles in the range from about 5 to 21 degrees) or flood lamps (beam angles in the range 21 to 60 degrees). You need to choose the...

You haven't answered my question - does the inverter operate with an earth reference - if not there is little point in considering RCDs as there would be no earth path for any fault current to flow back to the source. You might get an RCD to trip if there were any capacitive coupling but this...

Eric you are mixing many things here :D. First your references to UPS systems in general and the article on 'commercial' systems. The 16th Edition of BS 7671 has included requirements for such systems since 1997. The EWR has effectively had such requirements since 1989, and no doubt the...

These devices have been around for some time now but I have never seen one installed in the UK. There used to be a sales video on a GEWISS web site but I can't find it now. IMO they should be banned from domestic installations as I believe the philosophy behind them is fundamentally flawed...

I see many references to BS 8436 cables (Flexshield and similar) suggesting that it can be used to meet [522.6.5 (ii)], [522.6.6 (i)] and [522.6.8 (i)]. This is only correct if an assessment has been made of fault levels along the run of the circuit. Note that the fault level close to the...

Check out [433.3.1 (ii)] and then just take the fused spurs out - unless of course you can think of a way that a fixed heater load can produce an overload :D.

Would that be the same politicians that recently signed an extradition agreement with the USA :lol: . I started in this industry in 1965 so I have seen plenty of changes - some good, some not.