When does your surge protector need replacing?
Whole-house SPDs degrade incrementally with each surge event they absorb. Status indicators tell you when protection has dropped below useful — here's what to watch for.
By Steven Lockhart · Reviewed by Alex Towery, C-10 #989290
Updated 2026-06-16
Whole-house SPDs typically last 10-15 years in Marin's surge environment, but lifespan depends on absorbed surge energy. Status indicators (LEDs, audible alarms) signal when protection has degraded — most show green for normal, red or audible alarm for degraded. Replace when indicators show degradation, when an SPD is 12+ years old without indicators, or after a major surge event (severe storm, utility transformer failure nearby). Replacement cost: $400-$700 for direct swap; $700-$1,200 if upgrading model or adding features.
01How SPDs degrade.
Whole-house SPDs work by absorbing surge energy through metal oxide varistors (MOVs) or similar components. Each surge event uses some of the MOV's capacity; over many events, the cumulative absorbed energy degrades the device. Eventually, the MOVs can't clamp surges effectively, and the SPD provides only nominal protection. Critically, this degradation is silent — without status indicators, you don't know your SPD has degraded until a surge event causes equipment damage.
Modern quality SPDs (Eaton, Square D, Siemens, Leviton) include status indicators specifically because the degradation is invisible otherwise. LEDs show green when protection is intact, red or off when MOVs have failed. Some models add audible alarms or wireless notifications. Older SPDs (pre-2010 vintage especially) often lack indicators and should be replaced on a calendar schedule (every 10-12 years) rather than waiting for failure indication.
02Three triggers for replacement.
Status indicator shows degradation
Red LED, off LED, audible alarm — replace promptly. The SPD is no longer providing meaningful protection and the equipment downstream is exposed. Most replacements are direct swap, $400-$700, completed in a single 2-hour visit.
Age: 12+ years for indicator-equipped, 10+ for older units
Even without indicator changes, calendar-based replacement makes sense for older units. MOV degradation accumulates over years of small events that may not trigger indicator changes. We recommend planned replacement every 10-15 years.
After a major surge event
If your home experienced a significant surge (major storm, utility transformer failure nearby, equipment damage in the home), the SPD likely absorbed substantial energy and is closer to end-of-life. Inspect the indicator after major events; replace proactively if status looks degraded or you observed equipment damage.
03What we install for replacement.
Default replacement for most homes: Eaton CHSPT2ULTRA or Square D HEPD80, depending on panel make. Quality Type 2, well-built, good status indicators, 10-15 year design life. Cost $400-$700 for direct replacement. If the homeowner wants to upgrade — Type 1+2 cascade, higher surge capacity, smart-home integration with notifications — we discuss options during the replacement visit.
Replacement visits are efficient: 1-2 hours total including power down, swap, verification, and inspection scheduling. Permit required in most Marin jurisdictions for the replacement (same as initial install). For older Federal Pacific or Zinsco panels where the original SPD was installed years ago, replacement is sometimes a good prompt to discuss whole-panel upgrade — the SPD investment is small relative to panel safety.
Common questions.
How do I check my SPD's status indicator?
Look at the SPD itself (inside the panel cover or on the panel exterior depending on model). Most show a green LED for normal, red/off for degraded. Some have a window showing internal MOV status. Audible alarms are silent under normal operation and sound when MOVs fail. If you're not sure how to interpret your specific SPD, send a photo — we can identify model and status quickly.
What if my SPD doesn't have a status indicator?
Calendar-based replacement is the right approach. If your SPD was installed 10+ years ago without an indicator, plan replacement within the next year. The replacement is inexpensive ($400-$700) relative to the equipment it protects, and the modern replacement will have indicators for future monitoring. We can assess your existing SPD during a visit if you're not sure of its age or model.
Can I tell if my SPD has been absorbing surges?
Indicator-equipped SPDs show gradual or sudden indicator changes when significant surges occur. For SPDs without indicators, you can't tell directly. Indirect evidence: equipment damage during storms, frequent breaker trips, GFCI faults that don't reset cleanly. If you've observed any of these, the SPD may be at or near end-of-life and replacement is favorable.
Do I need to update my home's surge protection strategy when replacing?
Replacement is a good prompt to assess overall strategy. If your home has added solar, EV charging, smart panel, batteries, or other significant electrical infrastructure since the original SPD install, upgrading to Type 1+2 cascade or adding point-of-use SPD on critical equipment may be justified. We discuss current scope and recommend a strategy during the replacement quote.
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.
Talk to a licensed electrician in Marin.
Family-run, C-10 #989290, 20+ years in the trade. Honest scoping, fair pricing, work that lasts.