Radial Into Ring Questions

[winston1]

They will be rated at 240V so at 230V will be lower amperage.

Anyway - 0.04A

Here we go again. He most likely won't have 230v.

 

[EFLImpudence]

No, but you don't divide the 240V rating (3kW) by 230 to get the amperage.

 

[ericmark]

They will be rated at 240V so at 230V will be lower amperage.

Anyway - 0.04A

Is my maths going crazy? 240²/1500 = 38.4Ω and 230/38.4 = 5.989583 amp x 2 heaters so 11.97917 amp total so yes under 13 amp but 0.04A? think slight error there?

A few years back although official voltage was 230 volt it was in most places 240 volt, but with micro generation that has changed, at 240 volt the inverters on a sunny day could trip out on over voltage, so now 230 volt is actually 230 volt.

I have never understood why we can't get 16A FCU so we can use European equipment from a ring or radial, however in the main 13A is enough.

 

[winston1]

A few years back although official voltage was 230 volt it was in most places 240 volt, but with micro generation that has changed, at 240 volt the inverters on a sunny day could trip out on over voltage, so now 230 volt is actually 230 volt.

Maybe where you live, but here in London it is around 243v. Same in Isle of Wight. Most of Europe now measures around 235v, I have seen up to 240v in Germany. Budapest however still seems to be 220v.

 

[JohnW2]

Is my maths going crazy? 240²/1500 = 38.4Ω and 230/38.4 = 5.989583 amp x 2 heaters so 11.97917 amp total so yes under 13 amp but 0.04A? think slight error there?

You're probably not going crazy, but you appear to have missed EFLI's point ...

... it had been suggested that 2 x 1,500W heaters (i.e. 3,000W total) would draw "just over 13A". EFLI's response was that the 3,000W almost certainly relates to 240V, anyway (so that currents would be lower at 230V) but that, even if the 3,000W did relate to 230V, that would correspond to a current of 13.04A at 230V - i.e. "only 0.04A over 13A".

Kind Regards, John

 

[ericmark]

That makes more sense, as to voltage my old 65W fluorescent worked OK with 58W tubes for years, then it would only work for month or two, in the past volts around the 245 mark, on remeasuring dropped to 230 volt, so it was either change fitting or use LED tube.

Being lazy I fitted LED tube and by passed the ballast, new LED lasted just 18 months, and most of that time house empty, second LED tube does seem to be lasting better, but much less light to fluorescent lamp.

I suspect it depends on if anyone on the supply has solar panels? So high rise flats likely still 245 volt, but houses likely some panels so voltage dropped.

 

[JohnW2]

I have never understood why we can't get 16A FCU so we can use European equipment from a ring or radial, however in the main 13A is enough.

Well, you always have the option of putting a 16A MCB into an enclosure.

If there were a "16A FCU" it would presumably have to be a special design (designed to carry 16A) and would have to use a fuse which was different from (and mechanically incompatible with) a BS1362 fuse, since one wouldn't want people putting 16A fuses into plugs or 'standard' FCUs etc.

Kind Regards, John

 

[JohnW2]

That makes more sense, as to voltage my old 65W fluorescent worked OK with 58W tubes for years, then it would only work for month or two, in the past volts around the 245 mark, on remeasuring dropped to 230 volt...

You often tell that story, but I've always found it a bit hard to believe that there were tubes (or fittings?) around which presumably would/will not work satisfactorily in many countries in mainland Europe?

Kind Regards, John

 

[ericmark]

I am sure the fuse used in old Wilex fuse boxes could be fitted in a one gang back box to supply European 16 amp ovens. Would not want same size as BS1362.

If you could get a neat MCB then OK, but even the push button type fitted to reduced low voltage transformers are too long to mount in standard back box.

With a 32A cooker supply I see no problem with double cookef connection unit and supplying oven and hob. However with a 45A supply that seems a bit OTT for a 16A oven, clearly the oven could not be supplied with a 63A supply, but manufacturers don't seem to state max supply size, only min.

 

[JohnW2]

If you could get a neat MCB then OK, but even the push button type fitted to reduced low voltage transformers are too long to mount in standard back box.

Agreed. Having just had a very quick look around, there seem to be some "Tiny MCB modules", designed to fit into some sort of modular enclosure, in India!

Kind Regards, John

 

[ericmark]

You often tell that story, but I've always found it a bit hard to believe that there were tubes (or fittings?) around which presumably would/will not work satisfactorily in many countries in mainland Europe?

Kind Regards, John

It is not the tubes, it is the ballast which causes the problem. Ballast rated at 220 volt would work a 58W tube when designed for a 65W tube without a problem. But a 240 volt ballast would not.

While working on the building of Sizewell B we tried using 60W fluorescent tubes 110 volt the fitting was a standard 240 volt unit with an auto transformer with 110 and 127 volt tapings, the reduction in power required moving from 110 to 127 volt tapping was huge, typical 0.85A at 110 volt and 0.6A at 127 volt tapping.

This is why HF ballast is so much better, it auto adjusts to voltage variations.

However it was the lamp failure that prompted me to measure voltage. For most things a drop of 15 volt does not matter, but with magnetic ballast it makes a huge difference.

 

[JohnW2]

It is not the tubes, it is the ballast which causes the problem. Ballast rated at 220 volt would work a 58W tube when designed for a 65W tube without a problem. But a 240 volt ballast would not.

Fair enough, but given the inevitable variation in supply voltages (in any country), I'm a little surprised that they did/could not make one which would usually work anywhere in Europe (and beyond!). After all, even when the UK nominal voltage was 240V, some people had supplies potentially as low as 216V.

Kind Regards, John

 

[ericmark]

That was the problem with old magnetic ballast. Many times I have counted the fittings, with 58W fitting should be less than 0.25 amp but where 220 volt ballast used one would find a 6A MCB was tripping with 20 fittings.

The push for LED to save power over fluorescent is based on the now discontinued magnetic ballast, with a electronic ballast to gain if any is so small that one can forget about it.

 

[JohnW2]

That was the problem with old magnetic ballast. Many times I have counted the fittings, with 58W fitting should be less than 0.25 amp but where 220 volt ballast used one would find a 6A MCB was tripping with 20 fittings.

Fair enough. It is obviously inevitable that using a ""220V ballast", rather than a "240V" one will result in higher current.

However, both historically and now, the range of permitted supply voltages in all European countries is/was quite wide, so it sounds as if people might have been having problems with magnetic ballasts all over the place. I'm sure that, when you had your problems (and before the change in 'nominal' voltage', and before any actual changes due to PV etc.), there were many people in the UK with supply voltages of 230V or lower.

Kind Regards, John

 

[steve.mack]

Did I open a can of worms saying 230v or poke a hornets nest