DAVID E. SHAPIRO is a master electrician and renowned authority on home wiring. The author of OLD ELECTRICAL WIRING, also from McGraw-Hill, and the residential columnist for Electrical Contractor magazine, he has written for the Washington Post, Practical Homeowner, New England Builder, and many other magazines. He is also an electrical consultant and a certified inspector and plan reviewer. He lives in Colmar Manor, Maryland, near Washington, D.C., where he does business as Safety First Electrical Contracting, Consulting, and Safety Education.