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Posted: Mon Dec 12, 2011 11:58 am
by scotsmart
Hi there
i was wondering if anyone could in layman's english attempt to explain to me just what i should be seeking by way of either a petrol/deisel generator to act as a stand-by system to power the every day essentials with-in our home in times of need i.e. power cuts and such like (having just had a severe one here in Scotland this past week resulting in us having no heat for essentially five days and no light or anything else for that matter for three) we are actively seeking alternatives to be able to be used in conjunction with probably a solid fuel fire but also possibly to at some point take as much as possible away from core energy suppliers allowing us to be as SS as is possible?

So initially really the information i seek is thus, what size of generator would be required (silent type as we have one neighbour) to power basic things likes of a few lights (energy efficient ones of course) a radio, and keep our Tv possibly on, but allowing our IPad and phones to be charged when required and thats about it as anything more i beleive would require to massive a generator as to be price/size prohibitive anyway ?. so in KW terms what would i be seeking that wouldnt easily be overloaded running these items over an extended period? and where is the best place to obtain such an item, any idea on costs? and any other information required that would be usefull for us to know about, running, using, installing etc ...

My basic idea would be to wire a seperate circuit into our cottage that would supply a socket say in every room, which would only be used at such times as power cuts and such like where we could use the above items from, thus allowing us to continue living relatively comfortably no matter what is happen outside!!

As always any and all help, assistance or guidance would be appriciated


Re: generators

Posted: Mon Dec 12, 2011 6:10 pm
by John Headstrong
this is one of these things that really depends on how much you have to spend. I always go for cheap/recycled

solid wood fire is a must, try to get one with a flat top so you can make soup/stew during an absence of the national grid. stock up on wood and keep it covered.

so, for me the cheap and nasty is a £90 petrol genny like this ... rator-g720, placed out side near the shed, extension leads into the house and more leads into rooms running lamps, chargers, radios, TVs can pull too much power, so you might need to turn everything else off. you might also be able to powerup a combi boiler with a small genny that size, if it does not pull to much power on startup.

I like the idea of a socket in each room running from a alternative power source, a nice way to be off grid.

You could consider going for a 12v backup system. Some large leisure batteries and a 12v solar panel and/or windmill and a 600w inverter could also run your alternative sockets when you are not powering up the genny.

Re: generators

Posted: Mon Dec 12, 2011 6:37 pm
by scotsmart
Hi there many thanks for your reply!

I to partly from nessesity, but partly from not wanting to needlessly spend my hardearned :dontknow: i too dont enjoy overspending on anything, where we are located there is firstly a plentiful supply of both drift and tree wood lying about (anyone know the laws on fallen treees and the removl of their limbs? whilst i think about it)

I had one of those gennies in my motorhome but it was pretty much useless for all but the lowest useages sadly so it would need to be a much beefier model i fear than that, plus a silent or close to silent one so as not to upset my neighbours ( having finally found good ones after several years and several issues, threats and utter hell lastin three whole years i would rather not risk upsetting them or anyone else thanks) prefering to pay the extra costs involved

Yeah were not going anywhere anytime soon so reckon if we do it nice and efficiently/tidily as my pet hate is wires, i use an tablet pc now as the mass of wires required for my desktop without any
extras was just silly to be honest, my last home had every wire possibly raggled into the plaster
walls so i didnt see them ahhhhh i truly detest wires lying about apart from the obvious fire risks it
will take about the same amount of wire as extentions all over would and with twin sockets readily
available quite cheap, backboxes the same it should end up costing close to what it would any
other way, we would lay the wires if its possible shortly as we are shortly room by room going to replace all our carpets as they were mostly that horrible cheap cord rubbish so now is the time as they say....

So can anyone explain KW's as in what size would be an optimal size for sensible usuage.


Re: generators

Posted: Mon Dec 12, 2011 9:21 pm
by dave45
why are wires an "obvious fire risk"?

kW = 1000 Watts
and Watts = Volts x Amps (W=V.A)

so a 1-bar electric fire = 1000 W draws about 4 amps (assume 250 volts rather than 240v to make the mental arithmetic easier)
a 2kW kettle draws 8 amps
a 3kW kettle draws 12 amps.
a 10kW electric shower draws 40 amps.

If you want to know how much current an appliance draws read the label for info and use the "W=V.A" formula. For a real answer get your self a power meter (Maplins, Machine mart etc), which plugs between your appliance and the mains skt.

Size your fuses at the maximum current draw plus 25-50%

Re: generators

Posted: Tue Dec 13, 2011 1:25 am
by scotsmart
Thanks for that, "wires being a fire risk" i was refering to bundles of wires and extention cables all lying on top of one another as is found behind any tv or computer unit these days wires naturally heat up in use when power is going through them to a small degree x the sheer amount and you have a real risk of fire, we were taught that in school by the fire safety officers basic fire safety i would of thought ?

As for you KW explianation many thanls again but its still double if not treble dutch to me, let me try to explain what i wish to do that is leading me to enquire about the KW rating of a generator and maybe you could help me further (i certainly hope so amyway as im rather lost physics wasnt and isnt my thing)

The reason i ask is i wish to purchase possibly a generator to act as a short-term electrical supply to our home in times of power cuts etc (having just come through a 3 day one that froze and nearly drove us mad) now i am not expecting it to be able to power my entire home but a few of the essentials would be very helpful likes of a few lights (eco low wattage ones of course) and a few sockets from which i would run a tv, a radio, my home hub and charge my ipad and phone/s etc from, not nessesarily all at once but certainly likes of the tv & a light whilst charging the ipad type of thing, so what i need to know is of a silent variety what sort of rated generator would i need to run that sort of load continuiously and what sort of cost am i looking at, also silly question i know but to power my entire house (2 bed cottage all electric & storage heating) i mean i would never get one that big im just curious as to what it would need ? a small silent one will do me fine.

Again many thanks, looking forward to your reply.


Re: generators

Posted: Tue Dec 13, 2011 3:07 am
by KathyLauren
You don`t mention powering a refrigerator or a freezer, or powering a well pump. That`s fine if you have no plans to run them off the generator. If you do, the calculations above about watts, volts and amps still apply. However, you need to be aware that motors (and all the three appliances I mentioned have motors) draw double their rated power when they start.

A half horsepower motor might draw something like 400 watts when it is running, but for a second when it starts, it draws 800 watts. If you plan to run any motorized appliances, you need to plan for that surge. You have to assume that all motors can and will start simultaneously.

Your plan to install a separaate circuit for generator power is a good one. It must be physically impossible for the generator and the utility power ever to be connected to each other, even for the briefest time. There are numerous home-made connection setups that violate that principle. The consequence of messing up is that you could kill a lineman who is trying to restore your power. Unplugging each appliance from the utility circuit and plugging it into the generator circuit is a safe way to do it.

Re: generators

Posted: Tue Dec 13, 2011 3:56 am
by scotsmart
We intend to run a totally seperate circuit worry not probably going as far as to have different coloured sockets for it so no mistakes can be made?

As for fridges/freezers and the likes these we could shorterm do without it literally would be for say 3 x eco low wattage lights, out Tv, internet modem, and a phone/ipad charger and at no point would any/all be on at the onetime.

Let me explain we have im sure you will know here in the west of Scotland suffered a horrific storm that put our power out for three whole days and our heat out for five, so what im trying to do by a system much as i describe above enable us to be able to stay indoors with basic appliances this time around we were totally cut off ( no homephones as we have walkabout hansets that require
mains power to operate, no mobiles as mast had no power and no tv, radio to even know when it was likely to be back on) let alone im disabled with muscle deseases and require heat ( we intend fitting a multi-fuel stove to combat the cold issues).

So really all i need to know is say i walk into Machine Mart what model and output do i require to run such a power supply for periods of time without it tripping all the time.

THIS WOULD BE A TOTALLY SEPERATE CIRCUIT JUST FOR THE GENERATOR as i frankly do not fancy the alternative of running extention cables allround the property (ideally a transfer switched system that would cut in if power cuts but to run the whole house, storage heating, freezer and the rest i beleive would be far to large and expensive...

As always your input is invaluable and so helpful..


Re: generators

Posted: Tue Dec 13, 2011 7:04 pm
by KathyLauren
You are on the right track.

Just add up the watts of all the lights and appliances you want to run. Then add about a 50% safety margin to that total. That is the size of generator you want.

Re: generators

Posted: Wed Dec 14, 2011 1:09 am
by scotsmart
Ah right, ok thats sounds quite if not too simple :iconbiggrin: i shall give that a go tommorow and see what we end up with :dontknow:

I had a wee £90 one in one of my motorhomes through which was brand new and useless hence my trepidation in purchasing another to be equally as useless, is it also correct that power is lost from its total if wiring from it is to long, thus best to keep circuit as short as possible and take is through its on RCD as close to the generator (but obviously inside the house)

Again great advise thankyou look forward to your views on above.


Re: generators

Posted: Wed Dec 14, 2011 6:07 am
by KathyLauren
It is true that power is lost in long wirring runs. It won't be very much in your case, but it is still good to keep the wiring runs short. On the other hand, don't make them so short that the genny is right outside an open window or you'll gas yourself. I run mine 100 feet away from the house, because the biggest load I have is the well pump and that's where it is located. The lights don't mind.

Use the proper gauge of wire. I don't know what gauge is standard over there, but don't be under-sized. Sorry, I don't know what an RCD is, so I can't help with that.

EDIT: I just looked it up. RCD is apparently British for a GFCI. Yes, it is a good idea to have one.

Re: generators

Posted: Wed Dec 14, 2011 12:08 pm
by scotsmart
That is great, thanks for that makes considerably more sense now :iconbiggrin: just need to work out a decent size for it, the idea would be to have it housed in a small building, built to the size of whatever the genny is a type of shelter but there wouldnt be any open windows hence running the circuit thats one of the reasons it would stay plugged in all the time however onky being used if and when we had no power.
But most certainly would not have loose wires through an open window as that would surely defeat the whole purpose, of going to all the trouble of the wiring/sockets plan i would of thought?

Again many thanks for yoyr time, usefull comments


Re: generators

Posted: Sun Dec 18, 2011 8:13 pm
by pumpy
Hi Scotsmart, a 2.2 kva genny will run a kettle & thats about it. A 10kva genny would be good for about 35amps, so would be adequate to run the house but not the heating. If you are looking for a permanent installation, why not consider a change-over switch, altho' this would involve your local electric supplier connecting the mains to it. ( you have the mains connected to one side, & the genny to the other, then you just manually switch from one source to the other). Maybe worth a thought. Incidentally, nearly all gennies over 2.2 kva are diesel engines, so if you know of a supply of red diesel even better!

Re: generators

Posted: Sun Dec 18, 2011 11:39 pm
by scotsmart
Pumpy cheers for that, at last something i understand :iconbiggrin:

Yeah a friend in Barbados has a transfer switched system as they suffer a lot of power cuts over there i fear the UK amid more cuts may experience an ever increasing amount of such cuts as daily less and less maintenance is carried out i mean it was trees that took the main power cables out that rendered 1000's of homes powerless in Scotland this past week for four whole days and left us with no heating for five?

So now to search for appropriate sized gennys

Many thanks :cheers: