In the early 1980s, we installed post lights along our driveway. We lived on a flag lot then, and the driveway was about 200 feet long. The lights were spaced approximately 10 feet apart and were buried in concrete.

We made the mistake of not burying the wire deep enough, which came back to haunt us when we later used a rototiller. Also, we didn't use sturdy enough poles for our lights, so the job had to be redone a little more than 10 years later. Since then, we've learned a few things.

If you plan to install a light post, heed these important considerations:

• If you will be running new electrical wire, be sure that the wire is buried at least 18 inches. There are alternatives, but this is the safest and least expensive method.
• Even at a depth of 18 inches, we recommend you run your wire inside a large plastic conduit that is many times the diameter of the wiring. The tubing and the wiring should be waterproof and buried above and below layers of sand. This requires the trench itself to be deeper than 18 inches.
• Even if the circuit already exists, be sure that it is on a GFCI breaker. If it isn't, add one.
• If you are placing your post light on a pole that will be buried in concrete (as opposed to something bolted into a wall or curb), consider a post made from thick, heavy-gauge tubing or install the post into a slip-fitting (a sleeve in the concrete).

Running an electrical circuit outdoors differs quite a bit from indoor wiring. Outside, water and extreme dampness are involved. Also, exterior wiring run underground is somewhat more accessible than the wiring in wall and ceiling cavities. A rototiller, an aerator and a pick or a shovel easily can slice through or chew up an electric wire. In a split second, you can end up with a repair job that can take hours to complete and cost hundreds of dollars. Special wiring is available for direct burial. It has an extremely durable casing meant to resist damage by dampness, water and abuse. However, the casing is plastic and can be cut. The standard alternative is to run groups of individual wires in a plastic conduit. Better yet, we like running direct-burial wiring inside a conduit. It's the best of both worlds –sturdy, waterproof wire in a damage-resistant casing. Heat dissipation can be a minor problem here. Check with your local building department to find out what size conduit will work best for your project. Never use metal conduit below grade. It will rot in a matter of years. And always make sure to use wire that is 12 gauge or larger. Remember that 12-gauge wiring requires a 20-amp breaker.

Backfilling

Whether you decide to use conduit or the direct burial method, it is wise to backfill your trench with a little sand first. Then lay the wire and add a couple of more inches of sand and, finally, native soil. Sand is unlikely to damage the wire or the conduit. And, when you are digging in that vicinity, the sand warns you that wiring or conduit is near. If you can't bury your wire at least 18 inches below grade, cover it with a little concrete –3 inches to 4 inches is plenty, and about 8 inches to 12 inches wide.

Protecting a buried wire with a 4-inch by 12-inch concrete cover makes good sense. But be careful. Running a rototiller across a 4-inch by 12-inch concrete strip can ruin your day.

NOTE: All electrical connections should be made above ground in a special watertight junction box. In other words, if you plan to place the light 30 feet from the house, purchase a 50-foot-long piece of wire for the task. Any connections you make between the house and each light will add unnecessary expense to the project.

Never bury a high-voltage wire junction. It makes no difference if the connection has been contained in a waterproof box. Such boxes rust and can leak. Nothing will blow a fuse quicker than water, and there is much water underground.

If you must make a junction in the line, make it above ground. Be sure to use a watertight box to make the connection. We erred when we purchased our pole lights in kits and got second-rate poles; they lasted only about 10 years. Were we to do it again, we would either use much heavier poles or place less-expensive ones in sleeved concrete piers. In other words, we would either concrete in the best, or if less than the best was all that was available, we would be sure our assembly was such that the pole could be replaced without removing the concrete support pier. In this way, a less-expensive pole could be replaced in a matter of an hour or so, without any major complications.

When adding new exterior lighting, it is a code requirement to use a GFCI circuit. A GFCI breaker can be added to your electrical panel, but it might be easier, and far less expensive, to use a GFCI receptacle instead. You don't have to plug your exterior connection into the receptacle; you can wire directly into the back of it. It becomes its own mini breaker panel.

Finally, make sure that all electrical boxes and connections are waterproof. Do this under the auspices of your local building department. The alternative could prove to be shocking.