But with requirement 120.4, there is scope for new materials and products being brought on to the market post publication of current standards.
When and where would you consider we draw the line?
I would draw it before you get to the point of installing equipment where the maker
says that it performs in a particular way but can offer no independent verification of that or evidence which shows that it conforms to a standard which includes properly defined testing methods.
If a manufacturer is claiming it complies, they must be able to support this and who would/should be liable, taking in to consideration about manufacturers instruction etc....
You would both be liable if something went wrong.
Good luck getting the manufacturer to cough up.
or do we end up with the requirements being rewrote every time something new arrives?
That would be onerous, but the regulations could be written to say that any new products can only be used if they conform to their applicable BS/EN/etc standards.
Take these maintenance free JBs, for example. Don't you think that, just with traditional ones, and with all sorts of other wiring devices and accessories that there ought to be a standard to which they conform? Off the top of my head I can think of areas such as resistance to fire tested by a hot-wire, the ability to pass the current the maker says it can without overheating, the extent to which the spring contacts resist conductors being pulled out, how their performance holds up over time as multiple insertions and removals are done, as temperature cycles and mechanical stresses are experienced and so on.
I know that Ashley say
"Tests, including long term vibration, shock test, long term connection
test, pull out, voltage drop, temperature rise and exposure to
corrosive atmospheres validate the suitability of these terminals."
and it may seem cynical to say "well they would say that", but with no standards defined for what tests should be carried out, and how, and how the item should perform, then any maker can put any product onto the market and say it's OK. At the moment if you pick up a JB and it says "BS 6220" on it then (counterfeits apart) you know that it's got to conform to standards which the BSI consider necessary.
At the moment you have no guarantee of anything when you pick up a "maintenance free" JB.
[EDIT]Badly formed quote corrected.[/EDIT]