Not quite, but near enough.
If the UK leaves the EU, will the nominal voltage be changed back to 240v?
- Thread starter eveares
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They might.
They might.
They might.
You mean they would be experiencing a supply of 230V±10%.
As you have been told many times, to create a single harmonised supply specification.
Not much more though, <253 V.
Maybe, but do you think it is 'right' in electrical terms?
IMO, indeed so - and that Cmax should really be such that U0 x Cmax = maximum permitted supply voltage (not with the slight shortfall as with current Cmin!)! Does anything else make electrical/safety sense?
Indeed - see above.
If you don't regard it as 'safe' (and/or compliant with regs) to have a load drawing >40A through a 40A MCB, and if you accept that the supply voltage could theoretically be as high as 253V (hence about 43.5A), then presumably your electrical/common sense answer would be no? As I said, if you want a calculation that is going to be 'safe' for any permitted supply voltage, you have to calculate on the basis of the maximum permitted voltage. Why should 'a couple of amps' over the MCBs rating be OK if the supply voltage is 250V but not if it is 230V?
We are told [in 433.1.1(i)], I would say not unreasonably, that In of the MCB must not be less than Ib, and I have always assumed that Ib represents the actual current which does (or may) flow, not a figure derived from calculation on the basis of an arbitrary number which has no relevance to any particular installation. Maybe that interpretation is wrong? As above, it seems odd to believe that a couple of amps above the In of the MCB is OK with some supply voltages but not with others.
Kind Regards, John
Given Un=230, in what sense is [230 - (10% of 230) - (5% of 230)] 'not quite the same' as [230 - (15% of 230)]?
Kind Regards, John
Well obviously because if you start with too high a value at 230V then at maximum voltage of 253V it is going to be even worse.
I would say it is wrong, judging by the definition of nominal voltage.
230V plus 10% = current increase of 10%. For 9.2kW @ 230V = 40A plus 10% = 44A.
An MCB shall not trip at 113% of In. For In of 40A plus 13% = 45.2A.
If UK (possibly excluding Scotland) leaves the EU but wishes to be able to import and export goods and services, and to travel in and out without much hindrance, then we will have to continue to follow EU rules in many respects.
The difference will be that instead of being a leading member of the club and helping to make the rules, we will be outsiders having to conform but with no power.
Yes. Which, as I said in the other thread which seems to have evolved into a parallel discussion of the same issue, means that the U.K. would have relaxed its standards, i.e. supply regulation would not be as good as it is at the moment/was in the past.
Which is also what I said earlier: There is no reason for the change other than to be able to say that the U.K. now shares some Europe-wide standard. You don't seem to be disagreeing with that but seem to think it a desirable end in itself, and not the "solution" to a non-existent "problem."
A particular place has a supply specification with a voltage range A.
A piece of equipment is designed to operate over a voltage range B.
Range A is a subset of range B.
What prevents the piece of equipment with required voltage range B from working quite satisfactorily and safely when connected to a supply with a guaranteed voltage range A?
Let's clarify that: It would be to import and export goods and services to and from other EU countries.
But getting out of the EU would leave the U.K. in a much better position to trade with the rest of the world, since it would no longer be bound by the EU rules which dictate how the U.K. must trade with non-EU countries as well.
Because the 5% is within the installation, and is therefore 5% of 207.
According to the regs., isn't the percentage voltage drop supposed to be calculated using the nominal declared voltage? It always used to be.