Emergency Pond Power

[madmole]

OK, Some for those with more experiance of fixtures and fittings

I have a large Koi pond, That uses a fair bit of electron juice. Its now also housing a lot of large and expensive Koi. All filter and heating systems on it are redundant and failsafe

BUT of course Its only as good as the electricity supply. Its currently on its own Separate circuit RCD and 16amp MCB. So it wont effect the house and the house wont effect it

As an alternative failsafe power supply I will use my Land Rover (Expedition discovery, with twin battery, large solar array and 2000 Watt invertor, 110 amp alternator) and several weeks idle time on a tank

Now the invertor has 2 x 13 amp square normal sockets and the pond currently has several spare 13 amp sockets in the filter house (Supplied by 6mm SWA and has its own DB)

How can I connect the 2 together without ending up with a widowmaker? I wouldnt be too worried with an extension lead with plugs at both ends cos I would Isolate both ends and connect before energising, but hate the idea of even having such a lead in case someone else plugs it in thinking its a normal extension. Cant really have the lead permanently connected to the pond either.

Can you guys think of a suitable method of doing this that will not result in a potentially dangerous live fitting if a family member connects this up without isolation

I'm also concerned, how I will guarantee they have switched off the pond at the main CU so that when the supply is restored it doesnt fry my invertor and Alternator

Any ideas?

 

[RF Lighting]

You need a change over switch.

It allows either mains or generator power to supply your installation, but will only allow one at once.

 

[madmole]

Thanks RF, that sound like the ticket for ensuring only one supply at a time (why didnt I think of that)

Now need some ideas on making all connections safe

 

[electronicsuk]

16A commando inlet feeding one side of changeover switch, dedicated feed from DNO supplied consumer unit to other side of changeover. 13A plug with suitable length of arctic flex and 16A commando socket on other end to link between inverter and connections at the pond. Easy.

 

[madmole]

Thanks ElectronicsUK

Again, I wasnt seeing the wood for the trees, thinking the lead had to go to the pond when there was a perfectly good SWA already going there. Brilliant.

Will swap the existing JB (SWA to T&E to CU) in the workshop for a changeover switch and leave CU wiring intact, Then just suitable fixed cable to a IP56 comando junction on front of workshop where the Landy parks. Short lead for connection to landy. Jobs a good un,

Also means all doors will still close and lock! on workshop and landy

Thanks guys

 

[SteNova]

what happens if it goes off while you arn't there, is the change over switch automatic and the landy has automated start on it?

also how big is the fuel tank at idle my passat uses 0.7 liter per hour, so i would need 235 liters for 2 weeks

 

[madmole]

Auto swap over not needed. Can go for a few hours sans power. There are always folks around and I have a system that txts me if the power goes or water leaks. Also While I'm at work the Landy aint there!

Landy has expedition fuel tank on top of normal one, so 200 litres onboard. It doesn't need filling very often, but its a visit to the bank manager each time it does 8-( Anyway we are inside M25 and power cuts are not common or long lasting. I'm just planning for the worst

 

[ericmark]

You could use a UPS then change over built in. Or a battery charger and inverter all the time. We have same problem with the boat and shore power and unless you do something silly like a lead with two plugs it is simply a matter of unplug shore power and plug inverter into same plug as shore power came out of.

We considered contactors and change over switches but contacts can stick simple is best.

All really important stuff is 12vdc. The central heating pump for example if that fails it's a rake out fire quick job.

Not sure how much needs to run to ensure health of fish but I would look at some form of flow switch and a 12vdc pump so what ever fails independent system starts. I have used proximity detectors in past and a flap moved by fountain. For back-up likely a caravan water pump in a large sponge would do the job?

 

[LoveRocket]

Just be warned mate, that idling a Diesel engine for long periods is NOT good, not good at all!

 

[ban-all-sheds]

Neither is burning fuel just to keep some ****** fish alive in an unnatural environment.

 

[Steve]

Just be warned mate, that idling a Diesel engine for long periods is NOT good, not good at all!

Nip out every now and then and open the taps for a minute to burn up the crud in the engine.

 

[maltaron]

If idling a diesel is not good how do generators run for days at 1500 rpm.

 

[SteNova]

If idling a diesel is not good how do generators run for days at 1500 rpm.

"Engines used in electrical generators run at approximately 300 to 1000 rpm and are optimized to run at a set synchronous speed depending on the generation frequency (50 or 60 hertz) and provide a rapid response to load changes. Typical synchronous speeds for modern medium speed engines are 500/514 rpm (50/60 Hz), 600 rpm (both 50 and 60 Hz), 720/750 rpm, and 900/1000 rpm."

http://en.wikipedia.org/wiki/Diesel_engine

 

[LoveRocket]

If idling a diesel is not good how do generators run for days at 1500 rpm.

by 'Idle' I don't mean the speed at which an engine is running, but it running without a load. A diesel genset could be at full output but it's speed won't change.

Diesel engines on gensets are specifically designed to run at a set frequency depending upon the bus frequency and number of poles in the gen head. Do you think that a slow speed diesel engine running at 1000rpm is 'idling' because it's not screaming at 5000rpm?

It's also not good to run a diesel generator without a load on it.

 

[ericmark]

If idling a diesel is not good how do generators run for days at 1500 rpm.

One maybe 1500 rpm is not the idling speed for that engine I have worked on a National diesel with max speed of 150 rpm.
Two it does cause problems when run light load and as a result we use load banks to clear out the engines and test from time to time.

Finding small reliable diesels seems to be a problem and near every new narrow boat has one of the same pair of engines at about 44 BHP and they need no where near 44 BHP but the smaller options don't last.