Generators....

[SUNRAY]

For 'survival', yes, but in terms of 'normal use', although the medium-/long-term average will probably be in that ballpark, the short-term peak load would undoubtedly often be greater than 3kW - after all, that would only take "a kettle plus something else" - and generators are generally not very sympathetic to high peak loads, even if short-lived.

I also doubt whether, in the situation I mentioned, a DNO would use one generator to supply only one household - they'd then need a lot of (noisy!) generators to supply a street of houses!

Kind Regards, John

Yes of course you are correct, I'm thinking of 'survival' (as someone else described it) rather than full operation.

Last year we had a neutral fail in the distribution which resulted in all sorts of wierd effects down the street we had <100v. As we were in the middle of cooking dinner I got the camping stove in and a leisure battery/inverter to run a table lamp and kitchen TV.

A neighbour knocked on the door to find us sitting eating fairly normally to say power would be off for several hours.

Agreed my 300VA inverter (or for that matter my 650VA 2 stroke Genset) will not run my house by any stretch of the imagination.

 

[ericmark]

I lived for a time on the Falklands, you had to have a generator, so shepherds house would have an auto start 1.5 kVA generator really only for the lights, candles cause fires, so don't want candles. Small farm often two generators, 3 kVA normal use, 12 kVA for when shearing, on the settlements normally around 60 kVA would run twice a day, morning for the ladies to use vacuum and cool freezer, and evening think total run time around 10 hours per day, only Stanley and Mount Pleasant had 24/7 power, not all of Mount Pleasant my job included going to work an hour early and starting up the generators that powered the offices, 4 x 250 kVA Rolls Royce Eagle engines. Needed 3 on line for morning start up, but often could drop to two during the day.

Main accommodation block was 12 x 500 kVA 8 were V8 2 were V12. Stanley and latter Mount Pleasant used 1.5 MW units not sure how many, but as the building was completed started to use waste water for heating, it was all electric so the demand went down, the cooling water from generators actually heated the drinking water before it was processed, as the chemicals to treat water would not work if too cold.

So in UK we could live as the Falkland Islanders did quite well with a 3 kVA generators run twice a day, but auto defrost freezers would have to go. All chest freezers, an upright freezer time it will stay cold depends on where it was in relation to defrost cycle when it lost power, so full freezer only good for one hour guaranteed, it may be OK for 8 hours, but you don't know. Chest freezer normally will be OK for 12 hours plus if not opened and full.

 

[ericmark]

For 'survival', yes, but in terms of 'normal use', although the medium-/long-term average will probably be in that ballpark, the short-term peak load would undoubtedly often be greater than 3kW - after all, that would only take "a kettle plus something else" - and generators are generally not very sympathetic to high peak loads, even if short-lived.

I also doubt whether, in the situation I mentioned, a DNO would use one generator to supply only one household - they'd then need a lot of (noisy!) generators to supply a street of houses!

Kind Regards, John

Would you not boil water using a camping stove or the like? I lived for 3 years in a caravan with a 6A supply, 13A should be ample, even if you turn off some thing to run some thing else, even now most caravans only have 16A supply and rarely will it trip even with micro waves and induction hobs and 13A rather than the old 6A caravan kettle.

 

[SimonH2]

Yes, but in the context - getting a householder back online while the cable gang come and dig the street up for repairs - you would be dealing with people who often would be incapable of comprehending the instruction "don't use a kettle". Many people are so used to 24x7 lecky with effectively no restrictions that they could not cope with being told "max 3kVA" - to start with, many would not have a clue what that meant in terms of appliances they can and can't use.
A lot different if you've been brought up on weak supplies, part time genny, or something like that.
BTW Our friends across on mainland Europe are often on peak demand based tariffs enforced by an MCB - want a bigger MCB, pay more for your connection if the option is available at all.

 

[SUNRAY]

Would you not boil water using a camping stove or the like? I lived for 3 years in a caravan with a 6A supply, 13A should be ample, even if you turn off some thing to run some thing else, even now most caravans only have 16A supply and rarely will it trip even with micro waves and induction hobs and 13A rather than the old 6A caravan kettle.

It wasn't that many years ago that caravan supplies were only 5 or 6A and the inlet connexion was 50:50 Shuko or 4343.
My experience is domestic kettle are lower powered than they used to be, most seem to be in the 1200 to 1500W region now. We struggled to get a sensible power a couple of years ago when we replaced ours.

 

[EFLImpudence]

Where were you looking?
https://www.google.com/search?q=3kw...hrome.0.0l8.6158j0j7&sourceid=chrome&ie=UTF-8

 

[SUNRAY]

... you would be dealing with people who often would be incapable of comprehending the instruction "don't use a kettle". Many people are so used to 24x7 lecky with effectively no restrictions that they could not cope with being told "max 3kVA" - to start with, many would not have a clue what that meant in terms of appliances they can and can't use...

Having done a fair bit of temporary power, mostly for public entertainment reasons, I can only concurr with this.

For an event we will usually have a list of who wants what supply and where and I'd say 50% of them expect to plug more in than they ask for. Catering wagons are always wrong and we'll try to allow double for them.

Quite often the layout of the event is planned around power and it's quite common to supply 16A to several users when they say they have only small loads and then when they see a 13A socket spare the heavier loads appear.

We had one regular guy with an engraving machine rated at 150W and a fluo tube. suddenly he turned up with an oven and other machinary to make encapsulated items and didn't understand when we said he had to stop using them.

 

[flameport]

most seem to be in the 1200 to 1500W region now.

Only place I have seen such useless junk is in the USA, and that's because of their 120V supplies.

Of the first 30 kettles on the Argos website, the majority are 3kW with a few 2.2kW.

 

[SUNRAY]

Interesting... As I said a couple of years ago the vast majority were much lower powered when we looked at Argos and Currys.

The guy in Currys blamed a European directive which limited the power of vacuum cleaners, smoothing irons, hair driers and kettles. I haven't checked it but knowing what happened to Henry's etc it made some sense.

 

[ericmark]

I have the two kettles on two different sockets and likely still causing overload, both rated 3 kW although they only boil a cup at time, so not on for long but that sort of thing would really mess up a generator.

 

[JohnW2]

Would you not boil water using a camping stove or the like?

No, I would boil it on my Aga - which, given that it's powered by LPG is, I suppose a grown-up version of a camping stove

Kind Regards, John

 

[SimonH2]

Catering wagons are always wrong and we'll try to allow double for them.

A while ago I stopped at a roadside butty van* I'd not used before. Got chatting with the guy, and he'd learned how to manually prioritise loads - as in knowing that if the boiler and freezer (IIRC) both kick in then the genny gives up in disgust - so switching one off before switching the other on. I'd have mentioned it then but at the time I wasn't sure of my facts, and I've never stopped there again so haven't told him about priority/load shedding relays that would probably automate it for him.

We had one regular guy with an engraving machine rated at 150W and a fluo tube. suddenly he turned up with an oven and other machinary to make encapsulated items and didn't understand when we said he had to stop using them.

I'm slightly surprised you don't have setups with MCBs in-line - he'd soon learn that the oven just turns everything off As I said, over on the continent, some users are well used to living off restricted supplies that just turn off if they overload them.

The guy in Currys

Enough said**

blamed a European directive which limited the power of vacuum cleaners, smoothing irons, hair driers and kettles.

He was talking *******s. Vacuum cleaners, yes - everything else is complete *******s.
There was a scare story going round that they were going to power limit kettles as well - leading to long "discussions" here and elsewhere about the effects that would have. But actually they were NOT talking about restricting power - but looking at other features such as rate of heat loss once boiled, minimum fill levels (i.e. can you boil just enough for one cup) and ease of using that, speed of switch off once boiled. Basic factors, but ones that can add up to a fair amount of wasted lecky.

* That was one aspect of my last job that irritated me. I didn't get out of the office all that much, but when I did it was normally at the wrong times to be frequenting the butty vans - either too early in the morning for lunch, or too late in the afternoon and they'd all shut. We have some very good ones round here.

** Though to be fair, we've bought white good from them, and the staff we've dealt with have been very helpful, one even trying a load of permutations of offers to get us the best discount.

 

[ericmark]

The idea of measuring and pouring in just enough water into a kettle may sound good, but some one in our house would switch it on empty. I like the idea of a full kettle which only boils just enough, we have two Breville kettles, one is fixed output the other is variable and can be switched off mid flow, this one

is far faster than this one

the second I think has a leak off so it boils the same amount for a large or small cup, so economical with large cup, not so much with a small cup, the large picture you need right size cup, no way to get more or less.

I have often said why can't you get tea cosy for pans, with an induction hob not hot enough to burn it, but I suppose some one would try using it with a non induction hob.

 

[SimonH2]

We have one of those Breville jobs - the fixed one. We got it for our mother who was getting "a bit wobbly" with the heavy glass kettle she'd insisted on buying for herself. It didn't suit her cup size, so we got a variable one for her and we got the fixed one. I like the way you can press the button, leave the mug and teabag under it, and it'll brew a mug while you get on with other stuff.
You are right that the variable dispense size is done by boiling the full amount (max dispense) and then opening the "dump valve" for want of a better term. But for mum, it's a lot safer than the kettle - it was recommended by the local blind society. It works OK now that the carers and cleaners know to a) top it up, and b) not change the dispense amount to max or min when cleaning it.
You are right to doubt the "sanity" of many users. OK, he was getting on and didn't still have all his marbles, but a friend's father in law put a cordless kettle on the gas hob - the burning plastic didn't 'arf stink the house out

 

[JohnD]

I'm told the most economical way to boil water for a mug of tea is to put it in the microwave.