230V/240V Question

[ban-all-sheds]

If you mean that it was done with the intention that all European countries would, as a consequence, gradually move to actually providing a supply of average voltage 230V, then that would make sense.

I said nominal, not average.

AIUI the intention was for an eventual harmonised supply of 230V nominal, ±10%

If a 'standard loaf' were required to have a weight between 0.7 kg and 1.3 kg, it would make no difference to anyone whether it were described as having a 'nominal weight' of 0.7, 0.8, 1.0, 1.2 or 1.3 kg, provided enough additional information were provided to allow one to determine the minimum and maximum permitted weights.

It would make a great deal of difference if you needed to use the nominal weight of a loaf in calculations.

 

[stillp]

It was done for a very practical reason - it was done to create a new 230V European standard for nominal voltage.

If you mean that it was done with the intention that all European countries would, as a consequence, gradually move to actually providing a supply of average voltage 230V, then that would make sense.

If you mean something else, I would welcome an explanation, since I struggle to see any other point. Very many products have been labelled (and presumably designed for) "220V-240V" or "220V-250V" for decades, and that seems the obvious way to specify appropriate voltage ranges for products (and supplies). To arbitrarily declare some figure within that range as being the 'nominal' voltage would appear to achieve absolutely nothing, per se.

If a 'standard loaf' were required to have a weight between 0.7 kg and 1.3 kg, it would make no difference to anyone whether it were described as having a 'nominal weight' of 0.7, 0.8, 1.0, 1.2 or 1.3 kg, provided enough additional information were provided to allow one to determine the minimum and maximum permitted weights.

Kind Regards, John

[QUOTE="EFLImpudence, post: 3543053, member: 144975"
It is not arbitrary; it is the same as Europe.

Don't think that is the case. The tolerances are different in Europe.[/QUOTE]
Wrong. They are specified in a CENELEC standard, EN 50160.

 

[stillp]

Very many products have been labelled (and presumably designed for) "220V-240V" or "220V-250V" for decades, and that seems the obvious way to specify appropriate voltage ranges for products (and supplies).

Would you have inferred from that labelling that the product would not work at 219 V or at 251 V, or would you have expected a tolrance to be applied to that range?

 

[JohnW2]

I said nominal, not average.

I know you did, but, as I said in several posts, the 'on paper harmonisation' of nominal voltage would only really make much sense if the hope/expectation/intent that what would follow would be a gradual movement of average voltages towards that arbitrarily declared 'nominal' value.

It would make a great deal of difference if you needed to use the nominal weight of a loaf in calculations.

But you don't need that. Depending on the nature of your calculations, what you do need is the minimum, maximum or average weight - an arbitrarily defined 'nominal weight' which does not correspond to any of those is bound to cause the calculations to give inaccurate and/or unhelpful results. As I wrote fairly recently, in virtually all; engineering contexts, a 'nominal' measurement is the expected/intended/average value.

Kind Regards, John

 

[JohnW2]

Very many products have been labelled (and presumably designed for) "220V-240V" or "220V-250V" for decades, and that seems the obvious way to specify appropriate voltage ranges for products (and supplies).

Would you have inferred from that labelling that the product would not work at 219 V or at 251 V, or would you have expected a tolrance to be applied to that range?

Such ranges are almost invariably defined in statistical/probabilistic terms. In other words, to label something as suitable for use with "220V-250V" would indicate that 95%, or 99%, or whatever of specimens of the product would work satisfactorily if the voltage was within that specified range, with decreasing probability that they would work satisfactorily as the supply voltage fell below, or rose above, that range.

Kind Regards, John

 

[stillp]

Nonsense!

 

[PBC_1966]

The tags on appliances saying something like 220 - 240V AC 50Hz which have been around for decades are referring to suitability for use on supplies nominally between 220 & 240V, not that 220 is the absolute lower limit and 240V the absolute upper limit for proper and/or safe operation. They took into account normal supply tolerances and reasonable voltage drop in the installation. Remember that equipment more sensitive to voltage (many older TV sets, for example) had voltage adjustments, sometimes simple two-way settings such as 200-220 and 220-250V, sometimes with four or five possible settings.

 

[JohnW2]

A great deal would be gained if such children were officially labelled Stage 2 Children, but in some countries that meant 2-4, and in others 3-5. It would mean that once the age range was harmonised there would be a single market for the toys etc.

If you mean that it would be advantageous to harmonise the range of ages to which "Stage 2" refers, that is obviously correct and would make sense. However, to arbitrarily assign a numerical 'nominal age' (e.g. 2.5 years) to "Stage 2" would make very little sense.

In the electrical context, there is no reason why one should not have a literally 'nominal' (i.e. just a "name", not numbers) harmonised supply voltage (e.g. something like "EU Harmonised Voltage", or "EUHV"), but that would rationally then be numerically defined in terms of an acceptable range of voltages, not by some arbitrarily chosen number within that range (unless, as I've said, the plan was for average voltages to gradually move towards that arbitrarily declared 'nominal' value).

Kind Regards, John

 

[JohnW2]

Nonsense!

Is that directed at me? (a little quoting often helps ) If so, are you suggesting that a range of acceptable supply voltages which is already necessarily probabilistic (it can never be the case that equipment is guaranteed to work satisfactorily and safely at 220V and guaranteed not to work satisfactorily and/or safely at 219.9V!) should have a further probabilistic 'tolerance' added to it?

Kind Regards, John

 

[JohnW2]

The tags on appliances saying something like 220 - 240V AC 50Hz which have been around for decades are referring to suitability for use on supplies nominally between 220 & 240V, not that 220 is the absolute lower limit and 240V the absolute upper limit for proper and/or safe operation. They took into account normal supply tolerances and reasonable voltage drop in the installation.

Yes, that's true, I forgot to subtract and add the allowed tolerances - but what I wrote is otherwise true. In other words "220V-250V" meant/means that X% of specimens of the appliance would be expected to work satisfactorily and safely at voltages between (220V minus allowed tolerance) and (250V plus allowed tolerance), with decreasing probability that items would work satisfactory and/or safely as one moved away from that range.

Kind Regards, John

 

[stillp]

The tags on appliances saying something like 220 - 240V AC 50Hz which have been around for decades are referring to suitability for use on supplies nominally between 220 & 240V, not that 220 is the absolute lower limit and 240V the absolute upper limit for proper and/or safe operation. They took into account normal supply tolerances and reasonable voltage drop in the installation. Remember that equipment more sensitive to voltage (many older TV sets, for example) had voltage adjustments, sometimes simple two-way settings such as 200-220 and 220-250V, sometimes with four or five possible settings.

More nonsense! Some might have taken into account the supply tolerances, many were a statement of the absolute limits of the range within which some proportion of production would be expected to function. Whether that function was performed as well as it would have been at some nominal voltage within the range was and is another variable.

 

[JohnW2]

Some might have taken into account the supply tolerances, many were a statement of the absolute limits of the range within which some proportion of production would be expected to function.

The latter would seem fairly unlikely. "220V-240V" was common but I can't think of any European country whose supply was (both then and now) not permitted to go beyond one or both ends of that range.

Kind Regards, John

 

[stillp]

Some might have taken into account the supply tolerances, many were a statement of the absolute limits of the range within which some proportion of production would be expected to function.

The latter would seem fairly unlikely. "220V-240V" was common but I can't think of any European country whose supply was (both then and now) not permitted to go beyond one or both ends of that range.

Kind Regards, John

I was referring to PBC's statement about appliances, but you might be interested to learn that in the UK the supply voltage, and it's tolerances, represent a 10 minute average, so the supply could be a long way out of tolerance for some period less than 10 minutes.

 

[JohnW2]

I was referring to PBC's statement about appliances, but you might be interested to learn that in the UK the supply voltage, and it's tolerances, represent a 10 minute average, so the supply could be a long way out of tolerance for some period less than 10 minutes.

Yes, I know that and, worse, as westie was always telling us, at least the DNOs' interpretation (and maybe also 'the word') of the regulation is that even those 10 minute averages only have to be 'within range' for 95% of the time.

Kind Regards, John

 

[PBC_1966]

More nonsense! Some might have taken into account the supply tolerances, many were a statement of the absolute limits of the range within which some proportion of production would be expected to function. Whether that function was performed as well as it would have been at some nominal voltage within the range was and is another variable.

So on a slightly more recent British appliance which just says 240V AC 50Hz on it, do you think that means it's only guaranteed to work properly if fed with exactly 240V, and isn't designed to work on a range of about 225 to 254 volts?