Home Surge Protectors: What They Are and What They Protect
They help defend electrical equipment from voltage spikes caused by lightning, utility switching, and motor loads. They can reduce damage to electronics, appliances, HVAC controls, solar and EV chargers, and sensitive power supplies—helping prevent failures, extend equipment life, and avoid costly repairs.
HVAC
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Sensitive electronics: Modern HVAC units use control boards and sensors that can be damaged by brief voltage spikes.
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High-power motor switching: Compressors and blower motors create large inrush currents and switching transients that stress components.
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Outdoor exposure: Condensing units and long wire runs can pick up surge energy from lightning and utility events.
Appliances
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Sensitive electronics inside: Many appliances use control boards and power supplies that can fail from sudden voltage spikes.
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Motors and compressors: Fridges, washers, and HVAC-related appliances have motor loads that create and amplify electrical transients.
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Surges travel through wiring: Lightning, utility switching, and outages/restoration can send surge energy through home circuits into appliances.
EV Charger
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Sensitive power electronics: EV chargers use control boards and high-power conversion components that can fail from voltage spikes.
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Grid events hit hard: Utility switching, outages/restoration, and lightning-related surges can travel through the service panel to the charger.
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High-current switching stress: Frequent charging cycles and contactor switching can add electrical transients that wear components over time.
Question: Are whole-house surge protectors required by electrical code?
Answer: In many places in the U.S., yes—surge protection at the service is now required for homes.
Installed at the service entrance.
Listed for line-side use at the main disconnect.
What makes Type 1 different
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Line-side rated: Can be installed on the utility side of the main breaker/disconnect (where allowed by your installation method and local code).
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Built for the harshest surge location: It’s made to handle high-energy surges right where power enters the building.
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“First line of defense” in a layered system: It reduces the surge energy that reaches downstream panels and equipment.
What it helps protect against
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Lightning-related surges (nearby strikes that induce spikes on power lines)
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Utility grid events (switching operations, faults, and power restoration after outages)
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Large external transients coming in through the service conductors
What it helps protect
By cutting surge energy at the entrance, it helps protect everything downstream: your main panel and branch circuits, plus electronics like HVAC controls, appliances, computers, networking gear, smart home devices, solar/EV equipment, and more (often with additional Type 2/3 protection for best results).
Installed on the load side of the service disconnect.
The most common “panel-mounted” SPD used for whole-building protection.
What makes Type 2 different
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Load-side rated: Installed after the main breaker/disconnect, inside the electrical distribution system.
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Targets surges inside the building: It’s ideal for catching surges that come from the utility and surges created by internal switching loads (motors, compressors, LED drivers, etc.).
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Great for panel and branch-circuit protection: Can be placed at main panels, subpanels, or critical equipment panels to protect specific areas.
What it helps protect against
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Utility switching & power restoration surges that pass through the service equipment
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Motor and compressor transients (HVAC, refrigerators, pumps, shop tools)
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Internal switching spikes from electronics and power supplies (LED lighting, UPS/inverters, variable speed drives)
What it helps protect
By clamping surges in the distribution system, a Type 2 SPD helps protect downstream circuits and connected devices—including appliances, HVAC control boards, TVs, computers, networking gear, smart home devices, solar/EV equipment, and more. For best protection of sensitive electronics, it’s often paired with Type 3 point-of-use protection.
Installed at or near the device being protected.
It’s the “last layer” in a layered surge protection setup.
What makes Type 3 different
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Point-of-use: Located close to the equipment, not at the service/panel.
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Best for sensitive electronics: It’s designed to clamp smaller, residual surges that get past panel protection and to filter everyday electrical noise.
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Not meant for the harshest surge location: It relies on upstream protection (Type 1/2) to reduce the big surge energy first.
What it helps protect against
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Residual surge energy that remains after Type 1/Type 2 protection
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Everyday switching transients from motors, compressors, and power supplies
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Electrical noise/spikes that can cause glitches, reboots, or degraded performance
What it helps protect
Type 3 SPDs help protect sensitive plug-in equipment like TVs, computers, routers/modems, smart home hubs, gaming consoles, audio/video gear, security systems, and other electronics that are vulnerable to spikes and noise.
Why choose Bad Wolf surge protectors?
Bad Wolf surge protectors are built for real-world conditions—lightning, utility switching, and everyday electrical noise. Our products are designed for clean installs, dependable protection, and long-term reliability. When you want surge protection you can trust, choose Bad Wolf.
What makes us different:
• Made in the USA
• Options available for almost every application
• Rugged enclosures and clear status indication
• Support from a real U.S.-based team