Whole-House Surge Protectors
Protect your home's electrical system, appliances, HVAC equipment, electronics, and other connected equipment from damaging electrical surges. Bad Wolf offers Type 1 and Type 2 whole-house surge protection for 120/240V residential electrical systems.
A Type 1 SPD offers greater installation flexibility because it can be installed in appropriate service-entrance or load-side applications. A Type 2 SPD is installed on the load side of the service disconnect. We will help you understand the difference before you choose.
Two Types of Whole-House SPD
Both can provide whole-house surge protection. The important difference is where they are permitted to be installed.
Type 1 SPD
MORE INSTALLATION FLEXIBILITYDesigned for installation at the service entrance or in compatible load-side locations.
Type 2 SPD
LOAD-SIDE INSTALLATIONDesigned for installation on the load side of the main service disconnect, such as at a compatible electrical panel.
Type 1 vs Type 2: Know the Difference
Type 1 and Type 2 are both permanently connected surge protective devices used for whole-house applications. The biggest difference is where each type is permitted to be installed.
Service Entrance + Load Side
A Type 1 SPD is evaluated for installation at the electrical service entrance and may also be installed in compatible load-side locations.
Can be installed on the supply side of the service disconnect when permitted by the product listing and installation instructions.
Can also be installed on the load side, such as at a compatible main electrical panel.
Evaluated for the service-entrance installation environment, where incoming utility-side surge events may be encountered.
If you are considering a Type 2 SPD, you may also be able to choose a Type 1 SPD and install it in that same compatible load-side location.
Load-Side Installation
A Type 2 SPD is evaluated for installation on the load side of the service equipment overcurrent device.
Commonly installed at a compatible main electrical panel.
Can be used at compatible subpanels and other load-side locations.
Must remain on the load side of the service disconnect; it is not intended for supply-side installation.
Type 2 is a legitimate whole-house protection option when the SPD will be installed in an appropriate load-side location.
Where Can Each SPD Type Be Installed?
Type 1
Type 2
Being Told You Need a Type 2 SPD Does Not Necessarily Mean You Must Buy a Type 2 SPD
If the planned installation is on the load side of your service disconnect, both a properly selected Type 1 SPD and a Type 2 SPD may be suitable for that location. The Type 1 designation gives the SPD additional installation flexibility because it can also be evaluated for service-entrance applications.
Which Type of Whole-House SPD Should I Choose?
You do not need to be an electrical expert to narrow down your options. Start with where the surge protector will be installed and how much installation flexibility you want.
Will the surge protector be installed at the service entrance, or only on the load side of your electrical system?
You Want the Most Installation Flexibility
The SPD may be installed at or near the service entrance.
You want the option of installing the SPD on either the supply side or a compatible load-side location.
You are concerned about severe incoming surge events and want an SPD evaluated for the service-entrance environment.
You were told to install a Type 2 SPD but would like to consider a Type 1 model that can also be used in a compatible load-side installation.
When both types are suitable for the planned load-side installation, Type 1 often provides greater installation flexibility.
Your Installation Is Specifically Load-Side
The SPD will be installed at a compatible main electrical panel on the load side.
The SPD will be installed at a compatible subpanel or other load-side location.
There is no need for installation ahead of the service equipment overcurrent device.
You are comparing a specific Type 2 product whose electrical ratings and performance fit your application.
Type 2 SPDs provide permanently connected whole-house protection when installed in the appropriate load-side location.
Do Not Choose an SPD Based on Type Alone
Once you know where the SPD can be installed, compare the actual product specifications. Surge current capacity, VPR, MCOV, electrical system voltage, mounting style, and the needs of your home all help determine which surge protector is the better choice.
How Much Surge Protection Do You Want?
After choosing the appropriate installation type, the next step is comparing surge current capacity. Bad Wolf offers whole-house models ranging from compact protection to high-capacity and extreme-duty surge protection.
Learn About Surge Capacity ↓How Much Surge Capacity Do You Want?
After determining where the surge protector can be installed, the next specification to compare is its surge current capacity. This rating is normally shown in kiloamps, or kA.
kA Tells You How Much Surge Current the SPD Is Designed to Handle
A higher kA rating means the surge protector has greater surge-current handling capacity. It does not automatically mean the protector will limit the surge voltage to a lower level. That is why specifications such as VPR also matter when comparing SPDs.
50kA
A compact starting point for homeowners looking for permanently installed whole-house surge protection without moving into the higher-capacity product ranges.
- You want a compact whole-house SPD.
- Space and mounting size are important.
- You are looking for an entry point into whole-house protection.
100kA
A step up in surge-current capacity for homeowners who want more reserve capacity while still keeping the installation relatively compact.
- You want more surge capacity than a basic 50kA model.
- You have numerous electronic loads throughout the home.
- You want a stronger general-purpose whole-house option.
200kA
A high-capacity option for homeowners who want substantially more surge-current handling capability for the main electrical system.
- You want heavy-duty whole-house protection.
- Your home contains significant electrical and electronic equipment.
- You prefer additional surge-current capacity and reserve.
400kA
A very high-capacity whole-house option for customers who want substantial surge-current handling capability and additional capacity beyond typical residential starting points.
- You want one of Bad Wolf's highest-capacity residential options.
- You are looking for extreme-duty surge protection.
- Maximum available surge-current capacity is a priority.
Is a Higher kA Rating Always Better?
More surge-current capacity can provide additional reserve, but the highest kA rating is not automatically required for every home. Installation location, electrical system compatibility, available mounting space, VPR, MCOV, and the equipment you want to protect should all be considered together.
Now Choose Your Whole-House Surge Protector
Compare Bad Wolf Type 1 and Type 2 models by surge capacity, installation location, mounting style, and electrical specifications.
Popular Type 1 Starting Points
Bad Wolf Type 1 SPDs can be installed in compatible service-entrance applications and can also be used in appropriate load-side locations. Start by choosing the surge capacity and mounting style that best fit your electrical system.
50kA Series
Compact Type 1 surge protection for 120/240V split-phase electrical systems. A practical starting point for whole-house protection and dedicated equipment applications.
SP240V50KA — liquid-tight connection
SP240V50KA-A — direct panel mount with built-in 1/2-inch NPT male connection
100kA Series
A higher-capacity Type 1 option for homeowners who want additional surge-current handling capability in a compact whole-house protection system.
SP240V100KA-A — direct panel mount with built-in 1/2-inch NPT male connection
SP240V100KA-B — liquid-tight connection
200kA Series
High-capacity Type 1 whole-house protection for homeowners who want substantially greater surge-current handling capability and additional reserve capacity.
SP240V200KA — liquid-tight connection
SP240V200KA-A — direct panel mount with built-in 1/2-inch NPT male connection
400kA Series
One of Bad Wolf's highest-capacity residential Type 1 options for customers who want substantial surge-current handling capability and extreme-duty whole-house protection.
SP240V400KA — liquid-tight connection
SP240V400KA-A — direct panel mount with built-in 1/2-inch NPT male connection
Choose the Connection That Works Best for Your Installation
Liquid-Tight Connection
Provides installation flexibility when the SPD will be mounted near the electrical panel and connected using the supplied liquid-tight fitting.
Direct Panel Mount
Bad Wolf “-A” models use a built-in 1/2-inch NPT male connection for direct mounting to a compatible electrical panel or compatible 1/2-inch rigid electrical conduit.
Bad Wolf Offers Additional Type 1 Surge Protectors
The models above are popular starting points. Additional capacities, mounting styles, high-capacity designs, and specialized surge protection products are available in the complete Bad Wolf catalog.
Explore All Bad Wolf Type 1 Whole-House Surge Protectors
The popular models above are a good place to start, but Bad Wolf offers additional Type 1 capacities and mounting configurations. Compare the complete 120/240V split-phase lineup below.
Service-Entrance Capability + Load-Side Flexibility
These Type 1 SPDs can be used in compatible service-entrance applications and can also be installed in appropriate load-side locations when permitted by the product listing, installation instructions, and electrical system configuration.
50kA Series
Compact whole-house and equipment-panel surge protection for residential applications, HVAC, pumps, motors, and other loads.
SP240V50KA
Liquid-tight connection
SP240V50KA-A
Direct panel mount • 1/2-in NPT male
65kA Series
A compact Type 1 option for homeowners who want a step above the 50kA range while maintaining a small installation footprint.
SP240V65KA
120/240V split-phase Type 1 SPD
100kA Series
Six-mode Type 1 whole-house surge protection with panel-mount and liquid-tight connection choices.
SP240V100KA-A
Direct panel mount • 1/2-in NPT male
SP240V100KA-B
Liquid-tight connection
200kA Series
High-capacity whole-house protection with a choice of liquid-tight or direct panel mounting.
SP240V200KA
Liquid-tight connection
SP240V200KA-A
Direct panel mount • 1/2-in NPT male
225kA Series
High-capacity Type 1 whole-house surge protection from Bad Wolf's EMP-capable product family.
SP240V225KA
Liquid-tight connection
SP240V225KA-A
Direct panel mount • 1/2-in NPT male
HSD240V Series
High-capacity Type 1 whole-house surge protection with two distinct installation configurations.
HSD240V
Rigid plastic conduit mounting
HSD240V-A
Direct panel mount • 1/2-in NPT male
400kA Series
Extreme-duty Type 1 whole-house surge protection for customers who prioritize very high surge-current capacity.
SP240V400KA
Liquid-tight connection
SP240V400KA-A
Direct panel mount • 1/2-in NPT male
PHSD240V Series
Bad Wolf's very high-capacity PHSD Type 1 family for customers looking for substantial surge-current handling capability.
PHSD240V
Rigid plastic conduit mounting
PHSD240V-A
Direct panel mount • 1/2-in NPT male
HSD240V and PHSD240V Use a Different Connection Style
The standard HSD240V and PHSD240V models are designed for connection using compatible 1/2-inch rigid plastic conduit inserted into the device. They are not threaded liquid-tight models. The HSD240V-A and PHSD240V-A versions use a built-in 1/2-inch NPT male connection for direct panel mounting.
Compare the Complete Bad Wolf Surge Protector Catalog
Review additional specifications, applications, AC and DC models, accessories, mounting options, and specialized surge-protection products in the full catalog.
Load-Side Whole-House Protection
Type 2 surge protective devices are permanently connected SPDs designed for installation on the load side of the service disconnect. They are commonly installed at compatible main electrical panels and subpanels.
SP240V185KA
185kA 120/240V Type 2 Whole-House Surge Protector
The SP240V185KA is designed for homeowners who want a high-capacity Type 2 surge protector installed at an appropriate load-side location in a 120/240V split-phase electrical system.
185kA surge current capacity for high-capacity whole-house protection.
Designed for 120/240V split-phase residential electrical systems.
Intended for installation at a compatible main panel or subpanel on the load side.
Dedicated Type 2 configuration for customers whose application does not require supply-side installation.
Your Installation Is Definitely Load-Side
The SPD will be installed at a compatible main electrical panel.
The SPD will be installed at a compatible subpanel.
You do not need the option of installing the SPD ahead of the service equipment overcurrent device.
The SP240V185KA electrical ratings and mounting configuration fit your application.
You Are Not Necessarily Limited to Type 2
If your planned installation is on the load side, a properly selected Type 1 SPD may also be suitable for that same location. Type 1 additionally provides the flexibility of approved service-entrance applications.
Compare Type 1 Options ↑A Simple Look at the Electrical System
Type 2 SPDs are installed on the load side of the service disconnect. Actual installation must follow the SPD listing, manufacturer instructions, electrical code requirements, and the specific electrical system configuration.
Compare Installation Location Before Choosing
Type 2 can provide whole-house protection at an appropriate load-side location. Type 1 provides that same load-side flexibility while also allowing compatible service-entrance applications.
What Can a Whole-House Surge Protector Help Protect?
Modern homes contain electronics in far more places than televisions and computers. A properly installed whole-house SPD helps limit damaging transient overvoltages before they reach connected equipment throughout the home's electrical system.
Protection Starts at the Electrical System
Instead of protecting only one receptacle or one appliance, a whole-house SPD is connected to the home's electrical system so it can help reduce surge voltage reaching many connected loads.
Major Appliances
Refrigerators, ranges, washers, dryers, dishwashers, and many modern appliances contain electronic controls that can be vulnerable to electrical surges.
KITCHEN • LAUNDRY • HOUSEHOLD EQUIPMENTHVAC Equipment
Air-conditioning systems, heat pumps, furnaces, thermostats, and control boards can contain sensitive electronic components connected to the home's electrical system.
A/C • HEAT PUMPS • CONTROLSElectronics & Smart Home Devices
Televisions, computers, networking equipment, security systems, smart-home controls, and other electronics can all be affected by transient overvoltages.
TVs • COMPUTERS • NETWORKING • SMART HOMEEV Charging Equipment
Home EV charging systems contain power electronics and controls. Whole-house protection can provide an important first layer of surge protection for equipment connected to the home's electrical system.
EVSE • GARAGE • POWER ELECTRONICSPumps & Motors
Well pumps, pool equipment, lift pumps, irrigation systems, and motor-driven equipment can be exposed to surges traveling through electrical branch circuits.
WELL • POOL • IRRIGATION • MOTORSGarage & Workshop Equipment
Tools, battery chargers, compressors, controllers, garage-door equipment, and other connected loads can benefit from protection at the electrical-system level.
TOOLS • CHARGERS • CONTROLS • EQUIPMENTWhole-House Surge Protection Is an Important Layer — Not a Guarantee
No surge protector can make every connected device immune from every possible electrical event. Proper grounding and bonding, correct SPD installation, short conductor routing, and additional protection closer to sensitive equipment can all be important parts of a complete surge-protection strategy.
Consider a Layered Surge-Protection Approach
A whole-house SPD can provide the first major layer of protection for the electrical system. Additional SPDs can then be installed at selected subpanels or near especially important equipment when the application calls for additional protection.
Explore Whole-House Surge Protection in More Detail
The basics above are enough for many homeowners to begin choosing an SPD. If you want to understand topics such as VPR, MCOV, lightning, layered protection, surge capacity, and installation practices, our next section provides deeper resources without making this page unnecessarily complicated.
Explore Surge Protection Resources ↓Whole-House Surge Protection Resources
You do not need to understand every surge-protection specification before choosing an SPD. Start with the simple guides on this page, or explore additional Bad Wolf articles when you want more detail.
Start With the Basics — Explore More When You Need It
Homeowners can use the guides on this page to narrow down their choices. Installers, experienced customers, and anyone interested in the technology can continue into more detailed surge-protection resources.
Type 1 vs Type 2 Surge Protectors
Learn where Type 1 and Type 2 SPDs can be installed and why someone planning a Type 2 load-side installation may also be able to choose a properly selected Type 1 SPD.
Surge Capacity, kA & VPR
Understand what 50kA, 100kA, 200kA, and 400kA ratings mean and why surge-current capacity should not be confused with Voltage Protection Rating.
What Do Whole-House Surge Protectors Do?
Learn how whole-house surge protection can help protect appliances, HVAC equipment, electronics, EV charging equipment, and other connected loads from damaging transient overvoltages.
NEC Surge Protection Requirements
Explore how NEC surge-protection requirements have developed through the 2020, 2023, and 2026 code cycles, including requirements involving Type 1 and Type 2 SPDs and why local code adoption still matters.
How Surge Protection Has Changed
See how surge protection developed from early electrical protection methods to modern whole-house SPDs and learn why protection has become increasingly important as homes use more electronic equipment.
What Are VPR & MCOV?
VPR helps compare the measured surge voltage associated with an SPD's standardized test, while MCOV identifies the maximum continuous operating voltage the SPD is designed to withstand. Both are useful when comparing appropriate surge protectors.
Explore the Bad Wolf Blog
Browse additional articles covering surge protection, electrical code changes, EMP protection, generator applications, product technology, and other electrical-protection topics.
You Can Keep It Simple
Most homeowners can narrow down their choices by confirming the electrical system, choosing the appropriate SPD installation type, selecting the desired surge-current capacity, and choosing the mounting style that fits the installation.
Split Phase
or Type 2
kA Capacity
Mounting Style
Whole-House Surge Protection FAQ
Next, we'll answer common questions homeowners ask before choosing and installing a whole-house surge protector.
View Frequently Asked Questions ↓Whole-House Surge Protection FAQ
These answers cover the questions homeowners most often have when comparing Type 1 and Type 2 whole-house surge protectors, surge capacity, installation location, and protection levels.
You Do Not Need to Know Every Electrical Specification
Start with your electrical system, where the SPD will be installed, the surge-current capacity you want, and the mounting style that fits the installation. The questions below explain the details when you need them.
01 What is a whole-house surge protector?
A whole-house surge protector is a permanently connected surge protective device installed as part of the home's electrical system. It helps limit transient overvoltages before they reach appliances, electronics, HVAC equipment, motors, and other connected loads throughout the home.
02 Do I need a Type 1 or Type 2 SPD?
The first consideration is installation location. A Type 1 SPD can be used in compatible service-entrance applications and appropriate load-side applications. A Type 2 SPD is installed only on the load side of the service disconnect.
If your installation is definitely load-side, either type may be suitable depending on the specific product. If you want the greatest installation flexibility, Type 1 is often the better starting point to consider.
03 Can I use a Type 1 SPD where a Type 2 SPD would be installed?
Often, yes. A properly selected Type 1 SPD can generally be installed in a compatible load-side location where a Type 2 SPD might otherwise be considered, provided the product listing, installation instructions, and electrical system configuration allow that installation.
04 Is 50kA enough for whole-house surge protection?
A 50kA Type 1 SPD can be a legitimate compact whole-house surge protection option when its voltage, installation requirements, and other electrical ratings match the application.
Higher-capacity models provide additional surge-current handling reserve. Bad Wolf also offers 100kA, 200kA, 400kA, and other capacities for homeowners who want additional surge-current capability.
05 Is a higher kA rating always better?
A higher kA rating means greater surge-current handling capacity, but that does not automatically make it the best SPD for every installation.
Electrical-system compatibility, installation location, VPR, MCOV, mounting style, available space, and the equipment being protected should all be considered along with surge-current capacity.
06 What is VPR and why does it matter?
VPR stands for Voltage Protection Rating. It is based on the measured voltage associated with a standardized surge test of the SPD.
When comparing appropriate SPDs for the same electrical application, a lower VPR generally indicates that less surge voltage is passed on during the standardized test.
07 Where should a whole-house surge protector be installed?
The correct location depends on the SPD type, the home's electrical system, and the specific product instructions.
Type 1 SPDs may be used in compatible service-entrance or load-side applications. Type 2 SPDs are installed on the load side of the service disconnect, such as at a compatible main electrical panel or subpanel.
Keeping the SPD connection conductors short and direct is also an important part of good installation practice.
08 Can I install surge protection on subpanels too?
Yes. Additional surge protection can be installed at compatible subpanels as part of a layered surge-protection strategy.
This can be especially useful when a subpanel serves important equipment, a detached garage, workshop, HVAC equipment, pumps, EV charging equipment, or other significant electrical loads.
09 Does a whole-house SPD protect against lightning?
A properly selected and installed whole-house SPD can help limit lightning-related surge voltages that enter the home's electrical system.
However, no SPD can guarantee protection from every lightning event, especially the extreme energy associated with a direct lightning strike. Grounding, bonding, installation quality, and additional protection can all play important roles.
10 Do I still need additional surge protection for sensitive equipment?
Whole-house surge protection provides an important first layer of protection, but some installations can benefit from additional protection at subpanels or closer to especially sensitive or valuable equipment.
This layered approach can help reduce surge energy at multiple points in the electrical system.
11 Should a whole-house surge protector be installed by an electrician?
Whole-house SPDs are connected directly to the electrical system, so installation involves potentially hazardous line voltage. Installation should follow the product instructions, applicable electrical codes, and local requirements.
If you are not qualified and authorized to perform this type of electrical work, use a qualified electrical professional.
Bad Wolf Can Help You Narrow Down the Options
Tell us about your electrical system, where the SPD will be installed, the mounting style you prefer, and the level of surge capacity you are considering.
Need Help Choosing a Whole-House Surge Protector?
If you are still not sure which surge protector is right for your home, Bad Wolf can help you narrow down the choices. Start with your electrical system, installation location, desired surge capacity, and preferred mounting style.
Most residential applications on this page are for 120/240V split-phase electrical systems.
Determine whether the SPD will be installed at the service entrance, main panel, or another load-side location.
Decide whether you are considering compact, enhanced, heavy-duty, or extreme-duty surge-current capacity.
Choose between available liquid-tight, direct panel-mount, and other compatible connection styles.
Type 1 Whole-House SPDs
Review Type 1 models for compatible service-entrance and load-side installations.
View Type 1 Options →
Type 2 Whole-House SPDs
Review dedicated Type 2 surge protection for compatible main panels and other load-side applications.
View Type 2 Options →Complete Surge Protector Catalog
Compare additional Bad Wolf AC and DC surge protectors, capacities, voltages, mounting styles, and specialized products.
Browse All Surge Protectors →