Type 1 or Type 2? For most homes, Type 2.
UL 1449 splits whole-house surge protective devices (SPDs) into types by location and clamping capability. For Marin residential, the right answer is almost always Type 2 — here's the reasoning and the few exceptions.
By Steven Lockhart · Reviewed by Alex Towery, C-10 #989290
Updated 2026-06-16
Type 1 SPDs mount on the line side of your main breaker (ahead of the panel) and handle higher surge energy; Type 2 SPDs mount on the load side (inside the panel) and protect downstream branch circuits. For typical Marin homes with PG&E underground or overhead service plus a properly bonded panel, Type 2 is correct. Type 1 makes sense for homes with exposed overhead service in lightning-prone areas (rare in Marin) or commercial buildings with utility-grade requirements.
01What the Type 1/Type 2 distinction actually means.
UL 1449 (the standard that governs surge protective devices in the US) categorizes whole-house SPDs by where they're installed relative to the service-entrance overcurrent device. Type 1 SPDs are tested and rated for connection on the line side of the main service disconnect — meaning they sit between the utility connection and your main breaker. Type 2 SPDs are tested for connection on the load side, which in practice means inside the main panel itself. Both protect against transient surges; the difference is location, surge-handling capacity, and how the device fails safely.
Type 1 devices handle higher surge currents (typically 20kA-40kA per mode at higher in-rush) because they're closer to the utility transformer and see less impedance attenuation before a surge hits. Type 2 devices typically handle 10kA-20kA per mode and benefit from the wire-run impedance between the service and panel, which naturally attenuates fast-rising surge edges. For Marin homes on PG&E service with underground or short overhead runs, that attenuation is real and Type 2 is sized appropriately.
02When each type is correct.
Type 2 — correct for ~95% of Marin homes
Underground service, properly bonded panel, residential surge exposure typical of PG&E in Marin. Type 2 mounted inside the panel handles the lifetime of surges most homes will see. ~$300-$700 installed for quality models (Eaton CHSPT2ULTRA, Square D HEPD80, Siemens FS140).
Type 1 — overhead service, lightning-exposed, or utility-grade
Homes with exposed overhead service runs in higher-lightning areas, or where insurance/building inspector specifies Type 1. Mounts at the meter base or weatherhead. Adds $400-$900 over Type 2 cost. In Marin proper, this is rare — but homes in West Marin with overhead service may benefit.
Type 1+2 (combination) — best protection
Cascading Type 1 at service entry and Type 2 inside panel provides defense in depth. Type 1 handles the heavy surge, Type 2 catches what passes. Used in homes with extensive electronics, solar, or high replacement-cost equipment. ~$1,000-$1,800 installed.
03What we install in Marin homes.
Default for most jobs: Type 2 SPD inside the panel, name-brand model (Eaton CHSPT2ULTRA or Square D HEPD80 are our most common), with ratings appropriate for the panel (200A service gets a higher-rated SPD than 100A). We also install point-of-use SPDs on critical equipment (AV systems, computer workstations, EV chargers) as a second layer — point-of-use catches surges that originate inside the home (motor switching, equipment turn-on) that panel-level SPDs don't see.
For specific scenarios — overhead service, solar arrays, EV charging at high power, sensitive medical equipment, home server rooms — we recommend the Type 1+2 cascade. The incremental cost is modest relative to the replacement cost of protected equipment. We discuss specific recommendations during the panel upgrade or surge protection quote.
Common questions.
How long do whole-house SPDs last?
Quality SPDs typically last 10-25 years, but lifespan depends on how much surge energy they absorb. SPDs degrade incrementally with each surge event. Most modern units have status indicators (green/red LED, or audible alarm) that show when protection has degraded. We recommend visual inspection annually and replacement when status indicators show degradation — typically every 10-15 years in Marin's surge environment.
Do I need surge protection if I have solar?
Yes — and it's more important with solar than without. Solar arrays add a roof-mounted electrical entry point that creates additional surge exposure (lightning, induced surges from nearby strikes). Most solar installations include some SPD at the inverter, but adding panel-level Type 2 protection extends coverage to the rest of the house. For solar homes, we recommend panel-level Type 2 plus inverter-level SPD as standard practice.
Will a surge protector stop a direct lightning strike?
No — and nothing reasonably will. Direct lightning strikes deliver energy that exceeds any practical SPD's capacity by orders of magnitude. SPDs protect against the much more common scenario: induced surges from nearby lightning, utility switching events, and grid disturbances. For homes wanting genuine direct-strike protection, that requires a full lightning protection system (rods, conductors, grounding) which is a separate (and rare) project in Marin.
Can I install a whole-house surge protector myself?
We don't recommend it. Whole-house SPD installation requires opening the live panel, identifying proper breaker placement (some SPDs require dedicated breakers, others connect directly to bus bars), and verifying grounding/bonding is correct. The cost difference between DIY and professional install is small ($200-$400), and incorrect installation can compromise protection or create safety hazards. Permits are also required in most Marin jurisdictions.
How do you handle pricing — flat fee or hourly?
Both, depending on scope. Routine service calls and predictable scope (panel replacement, EV charger install, transfer switch install, fixture replacement) are flat-fee quoted up front. Diagnostic visits and emergency scope are hourly because we don't know what we'll find. Either way, you get a written quote before work starts on anything significant, and we don't proceed beyond the quote without your sign-off.
How quickly can you schedule?
Depends on scope and season. Emergency dispatch: same-day across Marin County (1-3 hours business hours, 1-4 hours after-hours). Same-day standard service: 3-6 hours from call when capacity allows; otherwise next business day. Scheduled service work: 1-3 weeks typical. Larger projects requiring permits and PG&E coordination: 4-12 weeks depending on scope. We're upfront about timeline at the quote stage.
What warranty do you offer on work?
Our standard residential warranty: 2 years on labor, manufacturer warranty on parts (varies by product — typically 1-10 years). Major installs (panels, generators, EV chargers) often have longer manufacturer warranties (5-10 years). If there's an issue with our work in the warranty period, we come back and fix it at no cost. We also stand behind work past warranty — repeat customers and referrals matter more than a transactional fix.
Are you licensed and insured?
Yes. California State License Board C-10 Electrical Contractor #989290, in good standing. Carry general liability insurance and workers' compensation insurance as required by California law. Bondable on projects requiring it. Happy to provide proof of insurance to clients or property managers on request. License lookup: cslb.ca.gov.
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