Shower related: watts and amps.

[JohnW2]

It is clearly a lie.. To say our voltage is 230 when it has always been and is still 240 is clearly a lie.

'Lies' or not lies, as I recently wrote, in all the years before the appearance of Cmin, using 240V rather than 230V for ADS calculations would have resulted in even more households potentially being left 'at risk'. Did you welcome that at the time?

Kind Regards, John

 

[JohnW2]

But the worse case situation is not considered when the calculations are done. .... The "official" calculations are restricted to using the "nominal" voltage and ignore checking that the current taken when the voltage is nominal +10% is still within the safe capacity of the cable and other parts of the circuit.

Indeed, and as I keep saying, the other way around, prior to the appearance of Cmin (which almost abolished the decades-old anomaly) the calculations we did (using the nominal voltage) to ensure the adequacy of ADS 'ignored' the fact that some households had supply voltages up to 6% below nominal, leaving those households potentially 'at risk'.

Undertaking safety-related calculations on the basis of some voltage which households 'might' have, rather than using the appropriate extreme (minimum or maximum) voltage that could be the case has always struck me as totally wrong, plain daft, and not 'safe'!

Kind Regards, John

 

[bernardgreen]

appropriate extreme (minimum or maximum)

appropriate extremeS (minimum AND maximum) should be calculated

 

[JohnW2]

appropriate extremeS (minimum AND maximum) should be calculated

No - not for a particular calculation.

Depending upon what calculation is being undertaken, the voltage one should assume (in the interests of safety, even if the regs say differently) is EITHER the minimum OR the maximum 'possible' ('permitted') supply voltage, as appropriate for the nature of the calculation.

Hence, for example, for proper/'safe' calculations relating to cable and OPD loading (i.e. current), one should assume the maximum possible voltage (253V), whereas for a determination of the maximum Zs of a circuit which will provide adequate ADS one should assume the minimum possible supply voltage (i.e. 216.2V).

Kind Regards, John

 

[ban-all-sheds]

It is clearly a lie.. To say our voltage is 230 when it has always been and is still 240 is clearly a lie.

Please take your own advice:

DON'T give out false information, it just confuses people.