Each home experiences 300-plus potentially damaging electrical surges per year. Home appliances and HVAC equipment, which depend on electronics, are sensitive to these surges. These units are a costly investment for the homeowner, and there typically is no protection.

A surge is a high-amplitude, short-duration electrical fluctuation that can cause harm to electrical, electromechanical, and electronic equipment. Surges are caused by lightning, utility events, and internal events:

Lightning is the most obvious and most sensational type of surge. Lightning can travel up to 1/2 mile from where it strikes. Nothing can prevent a direct strike.

Utility events consist of crossover of phases, capacitor switching, grid shifting, inductive loads, and open neutrals.
Internal events in the home, however, are the most likely source of a surge. A General Electric (GE) and National Power Labs (NPL) study shows that 65 percent to 80 percent of transient surges are caused internally from:

• Pumps (well or pool)
• A/C condenser motors
• Refrigeration motors
• Dishwasher motors
• Washer/dryer motors
• These events can result in the three D’s of surge problems: degradation (of equipment components), destruction, and downtime.

Surge Solutions

Surge protectors provide protection against:

• Incoming surges
• Bounce surges from inrush current; and outdoor moisture conduction from local lightning (as noted above, from as much as 1/2 mile away).

A surge protector works by shunting the voltage surge to ground. A good ground is imperative. The National Electrical Code (NEC) maximum resistance at ground is 25 ohms.