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The 'experiments' are carried out by the manufacturer when they design a device - they have the data - often available on their web sites or in technical literature. How much effort you put into any given design depends upon the potential risks. In a domestic installation the risk are...

BS 7671, and all other standards I am aware of, always assume a 'bolted fault' i.e. a short circuit of zero impedance. This is because it is often the worst case and, in any event, it is generally too difficult to consider impedances higher than zero when drafting regulations. If the DNO...

I have not paid much attention to most of this discussion so you may have covered these points. 1) Length of 'tails' - the DNO may allow the use of their protective device to provide overload and short circuit protection provided they are satisfied that the protection is effective. Each DNO...

Why - I would have thought the 16kA conditional rating on the CU should be enough :D.

Taken from a BEAMA Technical Bulletin.

Overload protection is provided by operation in the thermal region of an mcb (a fuse is all thermal :D).

Some of the confusion here may be due to not fully appreciating what a cable rating, as defined in Appendix 4, is. It is important to realize that it is the maximum 'continuous' rating. A cable can transmit much higher quantities of energy for short periods of time without any detrimental...

The notes to Appendix 4 detail the rational behind the various factors (see section 4) - further information is available in GN 6 Protection Against Over-Current, and various Commentaries on the Wiring Regulations. Appendix 4 is mainly the work of the organisation that was the Electrical...

The relationship is clearly stated in BS 7671 - 433.1.1 Ib <= In < = Iz and I2 <= 1.45 Iz I2 is the current ensuring effective operation in conventional time. Conventional time is a value stated for each device in its relevant standard. For BS 60898 mcbs conventional time is 1hour for...

For a single standby generator - that is only used as an alternative to the DNO supply - the main areas of concern for the DNO are the safety of their systems and staff, and limiting or removing any liability. They have made various statements over the years concerning the use of their earth...

Same thing http://en.wikipedia.org/wiki/Industrial_and_multiphase_power_plugs_and_sockets The recessed type ericmark posted is also the same (I have one on my yacht don’t you know :D). Which ever pattern you use make sure to mount it in a position where the risk of bumping into it, or...

I think LED street lights can produce 300 lumens / watt which substantially out performs SOX - however I don't know anything about the costs involved with them. I imagine we will see (or maybe not see :D) all sorts of money saving measures on street lighting pretty soon.

SOX lamps can produce 180 lumens / watt at 589 nm (close to the human eye peak sensitivity of 555 nm) - making them one of the most efficient light sources available in terms of energy. SON produce around 150 lumens / watt SOX used to be the first choice for street lights - however, their...

Oh yes he does - you are quoting a definition given in the metric version of the 14 Edition (it all went wrong when we went metric :D). It is not incompatible with the statement I made as it is saying will not operate at 1.5 times within 4 hours - whilst I was using a definition that says...

A BS 3036 fuse will actually allow 2 * In for up to 4 hours - we used to call it coarse excess-current protection :D. Mind you I can't remember climbing over too many bodies killed by ring mains - can you?

32A - are you certain ? Does that means I can design a ring final circuit protected by a 30A BS 3036 fuse to supply an assumed maximum load of 32A - oh goody :D.

The trip switch may be a Residual Current Circuit Breaker (Generic term RCD) which may be protecting the whole installation – it could even be an older voltage operated device. You will need to record all of the detail on it that you can see and post it - then someone might be able to be more...

Not one of these then :D

You have to read what 521.5.2 actually says - in particular read the bold heading. Single core armoured cable can be used as indicated in 523.10. They must not however, have steel armouring - they can and do have aluminium armouring :D.

Conduit to BS 61386 Conduit systems for cable management - is defined as equipment and as such meets 526.3 (v). A conduit system includes its couplers and other fittings.