Supplying Electricity to the Garden Pond
The combination of electricity and water can be lethal, particularly when a human being joins the two together, but if protected properly it is perfectly safe. The first rule is to make sure that all electrical equipment that is bought has been expressly made for outdoor use, and that all instructions, no matter how silly or inappropriate they may seem, are followed to the letter. The second rule is to keep it in good repair and well maintained. Where cables have to be used in the garden – especially if they are to be buried under flower beds – use an armoured cable (one that is covered with toughened plastic or metal). All switches and junction boxes must be completely waterproof.
If in any doubt about your system, call in a qualified electrician to advise you. Secure all cables so that they will not cause any hazard; avoid draping wires along a flimsy fence that could be blown down in a severe gale, and keep them out of hedges or shrubs that are likely to be clipped or pruned. If you decide to run the cable underground, bury it deeper than 45cm (18in) to prevent a garden spade inadvertently severing it. Also make sure that the cable route is clearly marked: you might remember where it runs, but if the house is sold the new occupiers need to know where the cable is to avoid trouble. A plastic strip is available to warn of buried cables. All this may sound too much trouble, but it is vitally important.
It is not always necessary to have full mains electricity to run pool equipment. The current can be stepped down through a transformer to a lower AC voltage or to very low DC voltage provided the equipment is’ suitable. If an accident occurs, the shock would then be well within safety limits and cause no harm.
As a safety precaution, all outside main circuits should be fitted with a circuit breaker so that if there is any leakage of current the circuit breaker automatically switches off the power. Choose a model that is suitable for personal protection, rated at 30 milliamps, and takes no more than 30 milliseconds to trip. This will ensure that if someone touches a live wire or a live section of a piece of equipment, then the instant the current starts to run through the person it will switch off before any damage is caused and the person will be unharmed.
There are various models of circuit breaker; they can be wired into the electrical circuit at the fuse box, or they can be wired in as a power socket or as part of a plug. The plug will cover only one appliance, but the socket, provided it has an adaptor, can service more than one item, and the circuit controller will cover all the machines on the whole circuit.
Lighting and heating
Electricity is not only for pumps but also covers lighting and heating. Here again it is important to use the right equipment – lights that have been designed specially for exterior use, either as individual lights or as strings of bulbs for illuminating the garden. Some lights for the pond are used floating or submerged, sometimes attached to a fountain to give a variety of colours to the spray. Most lighting comes in either flood or spot models: the flood will illuminate a wide area, whereas the spot throws a concentrated beam onto one feature, and gives a more dramatic effect. Where light is required to illuminate a hazard such as steps it is better to use a flood, which has a more overall light, rather than a spot, which can cause confusing shadows.
The low-powered lighting circuits that are available in kits complete with transformer allow the user to clip the lights directly into the cable, which is covered with a self-sealing plastic so that when the light is removed the cable becomes weatherproof again. The light can be placed anywhere along the length of cable without complicated cable stripping.
Where lighting cables are strung overhead it is necessary to support the wire with an additional stout galvanized wire secured to it with clips. Insulating tape is a short-term method that will rot after a year or two, leaving the cable unsupported. Plastic plant ties or clips will last much longer and hold the cable securely. A combination of both tape and ties is even better, as the tape will prevent any chafing.
Electricity provides a very convenient and easy form of power that gives light, drives motors and provides heating – the last is very useful when the pool becomes frozen in winter. Floating a special heater will keep a small area of the pool clear of ice; the fishes will benefit from the oxygen intake, and it will prevent the build-up of noxious gases under the ice. Sophisticated systems can be constructed using a thermostat so that the current is switched on automatically when the temperature drops below freezing and off again when it rises; this cuts down the current used to keep the pond clear.