If you have ever done any outdoor wiring, you know just how much money and work it takes to get the job done. In most cases you have to rip up your lawn and shrubs, digging ditches as deep as a foot or more. You have to work with conduit to protect exposed wiring, and you have to sink a lot of money into special waterproof fixtures and ground fault interrupters.

All that's enough to discourage most of us from attempting even the simplest jobs, such as installing a yard lamp near the driveway or front walk. But there is a way around all that work and expense. Use low-voltage wiring instead of normal 120-volt house current.

Low-voltage systems use transformers to reduce house-current voltage down to a safe 12 volts - the same voltage used in your car's electrical system or your son's electric train. It's so low you can touch exposed wires without being shocked.

As a result you can run your wires just about anywhere you want. No need to bury them in deep ditches or protect them with conduit. Just snake them alon gfences, string them from tree to tree, or conceal them in a slit cut in the ground.

One final advantage to low-voltage wiring: You need to permit to install it. That spares you what often can be along, frustrating wait at the building inspector's office, and also saves you the cost of the permit.

The easiest way to install low-voltage wiring is to buy a complete system. This will consist of a transformer, lighting fixtures and wire. Depending on your needs, you can get a set with anywhere from two to 12 fixtures. The fixtures are made in four basic types, each with a different purpose:

Floods and spots are the workhorse lights. Floods are the best choice to illuminiate relatively large areas such as a patio or basketball court. Spots are for highlighting smaller areas or a feature of your home you want to accentuate at night. Both floods and spots are usually mounted up high, so most have bases that you can screw or nail to trees or your home.

Mushroom lamps are best used along walkways. Most are about two feet high and come with pointed mounts you can simply stick into the ground. This simplifies installation, and lets you move the lights out of the way when you mow the lawn.

Globe lamps emit diffused light in all directions. They are best for decorative lighting around interesting landscaping features. Like mushrooms, they often come with pointed mounts for on-gournd installation.

Twinkle lights are also largely decorative rather than functional. They feature a pierced housing surrounding the lamp. As you move past these lights, rays emerging from the piercing catch your eye and create a twinkling effect.

Installtion is simple. The transformer simply plugs into any existing grounded outlet. Fixtures connect to the low-voltage cable by means of simple press-on fittings. Complete systems and separate components are sold by most hardware and garden stores, as well as electrical supply houses.