Useful and interesting (as ever) stuff.
A few tiny comments from a layman:
Extra Low Voltage
Add to the heading "or ELV" for consistency with the preceding "Low
Voltage or LV"
You will probably already have spotted the typo in line 1 of "wore" for
Why is Neutral a Live wire?
In penultimate line similarly a typo of "(this" for "(This"
I couldn't find anything which replaces the +10/-6%. And the guys at
http://www.voltageoptimisation.com/ state that "In the UK, the statutory
supply limits have not yet been fully harmonised, with a somewhat
tighter tolerance still in force: 230V +10%/-6% (216-253 Volts).
Background to the change to 230V
Any value in adding at the end something like:
"In 1994 the legislation governing the supply of electricity was
amended to require 230 volts rather than 240 volts between the phase and
neutral conductors; but at the same time it allowed supply at 10% above
(rather than 6 %) or 6% below. The net effect was that (within rounding)
suppliers didn't have to change their practice.
The legislation in 1994 was the first stage in harmonising
voltages across the EU."
 The Electricity Supply Regulations 1988 S.I. 1988/1057
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