Proof that The Man from Salford doesn't eat too much!

Some strange crackling and fizzing has been emanating from the generator room, sparks are flying and electricity is wildly arcing.  What has The Man from Salford being doing?  I suspect he is building a new wife.  A wife who will let him eat steak whenever he wants. A wife who will let him have a cat and a Rhodesian Ridgeback puppy (and let that eat steak whenever it wants.)  And a wife that doesn’t accidentally spill her vile comfrey tea all over his clean overalls.

As I’m pondering the advantages of such an arrangement, (perhaps she can do all the housework?) I fear we might both become widows before we’ve sorted out the exact details.  Any minute now The Man from Salford will be lit up from the inside like an x-ray cartoon of himself and I will have to figure out how everything works on my own. 

I have spent the best part of the last forty years happily watching televisions, using phones, being transported in cars, tapping at keyboards and generally getting what I want at the flick of a switch and I am ashamed to say I haven’t got the foggiest clue how all these things actually work.  I really do marvel at humankind’s ingenuity.  Yet, if you are thinking of living off-grid then it is probably a good idea to start getting to grips with some of the basics as it is likely you will have to carry out at least some routine maintenance yourself. 

Whatever kind of off-grid system you have none of it will be much good to you until it is properly wired and connected together.  We have, as I’ve mentioned before, a 24v Trace inverter, a battery bank consisting of 12 two volt deep-cycle batteries and an 18kw diesel generator.  In addition to this we have a 12v back-up lighting system.  12v back up systems are becoming increasingly popular choices, even for those on the grid, as extra security in the event of intermittent mains power supplies.

Our 12v system is very rarely used except by visiting guests who have no idea what they’re switching on.  As this system was put in first the switches get pride of place by doors, you have to grope around in the dark to find the AC appliances. On very dark, moonless nights we sometimes use the 12v to help us find my our way from the bedroom door to the bed! 

Cabling installation for low voltage DC systems doesn’t vary wildly from those for standard mains, however, some extra consideration should be given to cable size and type, and you need to give some thought to durability and how you will protect cables from damage.  

In most conventional domestic electrical installations cable is simply selected on its current-carrying capacity.  With low voltage systems the current for any type of appliance will be much higher than an equivalent mains appliance so the cable needs to be much thicker in order that extra current can be carried without overheating.  

Resistance from the copper in any cabling system causes ‘volt drop’ and here is another difference between conventional mains systems and low volt systems.  As current travels along a cable some power is lost along the way due to this copper resistance, the higher the current and the longer the cable the greater the volt drop. 

Low voltage systems require much thicker cabling than you might suspect, not just to carry current without overheating but to allow for voltage drop.  A voltage drop of 2v in a mains 240v system wouldn’t even cause a flicker, but a drop of 2v in a 12v system is unacceptable.  Appliances will not function properly or, as if often the case with TVs, not at all.  In a twelve volt system you cannot afford a drop of more than 0.6v.  Typically a cable of 10m length for a circuit up to 288W with a 24amp current requires a minimum cable size of 16mm², increasing to 35mm² for a cable length of 30m.

 What kind of cable should you use?  As always cost will be a factor. PVC twin core cable is the cheapest option and a popular choice for indoor DC wiring, but even indoors requires protection and should be carefully routed or covered with protection strips.  Multi-strand cables give a better defence against conductor damage and should be used where cables may experience movement.  Sunlight does eventually degrade PVC and outdoor cables can be placed inside polythene water pipes.  Steel-wired-armoured cable, while very expensive, is probably the best choice for outdoor cabling and can be sunk into the ground.

I eventually pluck up the courage to stick my head into the generator room and ask The Man from Salford what exactly the problem is.  Mice have eaten through our cable!  This wouldn’t be quite so bad if the expansion tank into which we pump water wasn’t also leaking all over the place.  I’m guessing we don’t have steel-wired-armoured cable.  So what sort of cable do we have?  ‘Cable, cable?’ shrugs The Man from Salford.  Perhaps I should let him have a cat after all, in place of a regular maintenance routine this may be our best defence against damaged circuits!

If you’re a boater or caravaner, or like us live off-grid, you might have come across these fine pieces of electrickery.  For those of you who still feel clueless I’ll explain as best I can.  My apologies in advance if you are a physicist.      DC or direct current is the sort of current you get from a battery, picture it like a straight line please.  AC or alternating current is the current that feeds all the electrical appliances in your house, this is an altogether more wibbly-wobbly affair – o.k just picture a wavey line, or sine wave to give it a proper name.  What an inverter does, is to convert that straight line of current stored in batteries into a wibbly-wobbly current that can power household appliances such as lights, TVs, and computers.

This is something that revolutionised  our quality of life. You might remember my post on how wasteful our generator is, (see Genny Tales: The Dark Ages) well the good news is that now we can do our housekeeping at a sociable hour.  When the generator is running the inverter is busy using all that excess energy that might other wise be wasted to charge up our battery bank consisting of twelve two-volt batteries.    This means we can arrange our lives a little more conveniently, no more traipsing to and from the genny room with washloads at ten o’clock at night.  We can run the generator for a couple of hours during the day if we need to and make use of high draw electrical appliances such as washing machines and dryers during this time, knowing the batteries are charging up for the rest of the day when we might only be using a few lights, a TV or a computer.  Most people can no longer tell that we don’t have mains electricity, there is some minimal tell-tale light flickering when we change over from genny to batteries.

We are of course, still using the genny as much as we used to, but we are getting more out of it, it is less wasteful.  The important thing is we now have some of the equipment in place, batteries and inverter, needed to make most forms of renewable energy work on a domestic scale.  For many domestic settings, the cost of  wind turbines or electric solar panels plus the inverters and batteries, means that  householders could wait years to recoup their expenses.  We are already half way there however, and when we last made enquiries, about a year ago, it was estimated it would cost us £45 000 to have mains electricity installed.  Time to research wind and solar power I think!   

I’m gradually getting over my allergy of candles and learning to love them again.  I’m getting much better at looking pleasantly surprised when people who don’t know about my days in the dark ages buy me a candle as a gift!      

 We have an F.G Wilson 1800 kilowatt diesel powered generating set.  It will not, as I’m fond of telling passers-by light up Blackpool, it will of course only light up 18000 one-hundred watt bulbs.  But my point is, it’s wasteful.  Imagine if all the electricity you are using is just a bedside light to read by, you really don’t want to be burning up all that diesel.  There are only certain times of year, usually late summer after Sam, our farming neighbour, has had a chance to cut the grass in his fields, that we can get a tanker down to deliver fuel.  One of the aims of this project is to do everything we can to lessen our dependence upon diesel supplies, whilst still maintaining some semblance of a civilised existence.

 Once upon a time we lived in a lot of darkness because of the wasteful nature of the generator.  We would only turn it on when it got so dark it wasn’t possible to see, and then there would be a mad, late night flurry of electrical activity – hoovers, washing machines, tumbler dryers, stuff that needed drilling and then we might treat ourselves to watching TV or using a computer by bulb light.  After our weirdly timed house-keeping rituals were completed, it was a toss up to see who was going to go slipping down the slippery slope in their pyjamas and wellies to turn the generator off – if you were quick enough it was possible to run back to the front door before the lights completely dimmed and you were pitched into utter blackness.

Living like this was an education.  We learned that you could still do a lot of stuff without electricity, we certainly learned not to take it for granted – even now, flicking a switch and something happening is a cause for delight!  We learned to be extremely careful with our water supply, because without the genny running the pump wasn’t running – so we had to eke out what was in the tank until we next switched on.  Having to fill a bucket with canal water on a cold day so you can top up a toilet cistern,  undoubtedly  makes a water conservationist out of you.

While we may have learned a lot about what we could do without, I don’t think we considered it an ideal way to live.  I would like to think this project will convince people that a sustainable lifestyle is in fact a desirable lifestyle, and that’s going to take more than a love of candles.  There is, also,  no denying that however little diesel we were using we were still using something irreplaceable and we were still upping our carbon footprint.  We knew something would have to change and it certainly did.  For starters, Goldilocks was born which definitely changed things, and shortly after her arrival the inverter arrived – and then there was light!