Surge Protection Reference
Why this matters
Power surges damage electronics + appliances + cost insurance claims. Whole-house surge protection costs + protects + of customer equipment. The electrician who sells + installs whole-house surge gets recurring service relationships + protects customer property. This is the field card.
Types of surges
Lightning-induced: direct strike OR nearby strike; ultra-high voltage; mostly destructive.
Utility-grid surges: power restoration after outage; voltage spikes; cycling damage.
Internal switching surges: motor starting / stopping (HVAC, refrigerator, well pump); cumulative damage.
Wiring fault surges: ground fault in adjacent equipment; back-feed.
Surge protection categories
Type 1 (service entrance, outside meter base): highest capacity; for direct lightning; installed by utility OR commercial.
Type 2 (panel-mounted, residential): most common; mounted in OR near main panel; clamps surge to ground.
Type 3 (point-of-use, plug-in OR receptacle): surge protector strips; protect individual devices.
Whole-house protection: combination of Type 1 (sometimes) + Type 2 (always) + Type 3 (selective).
How surge protectors work
MOV (metal oxide varistor): voltage-dependent resistor; conducts surge to ground when voltage exceeds threshold.
Other components: GDT (gas discharge tube), SAD (silicon avalanche diode).
Indicator lights: green = working; red = failed; needs replacement.
Joule rating: total energy absorption capacity; higher = more surges before failure.
Clamping voltage: threshold at which protector engages.
Whole-house surge protector (Type 2)
Installation location: inside main breaker panel OR side-mounted external box.
Connection: two-pole 240V breaker; connects across line + neutral + ground.
Common brands: Square D HEPD, Eaton CHSPT, Siemens BoltShield, Intermatic IG2240.
Capacity ratings:
- Residential basic: 40,000A surge
- Premium residential: 80,000A surge
- Commercial / high-risk: 120,000A surge
Joule rating:
- Basic: 1,000 - 3,000 joules
- Premium: 3,000 - 6,000 joules
- Top-tier: 6,000+ joules
Multi-mode protection: L-N, L-G, N-G all protected.
Type 3 point-of-use protectors
Datacom / RJ-45 surge: protect ethernet from surge into router / switch.
Coax surge protectors: protect cable / antenna / satellite lines.
Phone line surge protectors: protect modem / phone equipment.
TVSS combo (TV / satellite / phone): integrated.
Surge-rated outlets
Indicator LED: shows protection status.
Common brands: Leviton, Pass + Seymour, Hubbell.
Use: home theater, computer area, important appliances.
Surge protector failure modes
MOVs absorb surges: degrade with each surge.
End-of-life signal: indicator LED off OR red.
After major surge: replace immediately; MOVs may be exhausted.
No protection without working MOV: silent failure if not checked.
Lifespan: 3 - 7 years residential typical; less in high-surge areas.
Where to install whole-house
Mounted on panel (interior):
- Direct-connect to two-pole 30A breaker
- Easy install + visible indicator
- Most common residential
Mounted external (NEMA 3R box):
- Outside panel for larger units
- Premium / commercial
At service entrance (Type 1):
- Outside meter; before main panel
- Catches surges before reaching panel
- More common commercial
Customer assessment
Past surge damage? If yes, customer understands value.
High-value electronics? Home theater, gaming, multiple computers, home office.
Areas prone to lightning? Florida, Gulf Coast, Mountain West.
Utility grid stability: rural OR aging infrastructure = more surges.
Insurance discount? Some insurers offer discount with whole-house surge installed.
Install procedure (residential Type 2)
- Power off main breaker
- LOTO + verify dead at panel
- Position surge protector (back of panel OR side-mount enclosure)
- Run conductors to panel (typically 10 AWG hot wires + 12 AWG ground)
- Connect to two-pole 30A breaker (some require 20A; check spec)
- Connect ground to grounding bus
- Close panel + restore power
- Verify indicator LED on / green
Common surge protection mistakes
Skipping whole-house (point-of-use only doesn't protect HVAC + appliances). No indicator check (silent failure). Mounting upside-down (some require specific orientation). Using wrong gauge wire. Wrong breaker amperage. Skipping ground OR misconnecting. Not advising customer to replace after major surge.
Layered protection (best practice)
Layer 1: utility-side surge arrestor (if available; meter base mount).
Layer 2: whole-house Type 2 in main panel.
Layer 3: point-of-use Type 3 for sensitive electronics.
Each layer reduces voltage: combines for ultimate protection.
Surge from utility restoration
After power outage: utility re-energizes circuit; voltage spike common.
Customers report: appliance dies day OF outage restoration.
Whole-house surge: protects against this.
Recommend turning off main breaker during multi-hour outage; reset after utility stable.
Lightning strike protection (separate but related)
Lightning rods: not surge protection; ground direct strike to earth.
Lightning protection system (LPS): complete grounding system; UL Listed; for structures in lightning-prone areas.
Whole-house surge protector: doesn't protect against direct lightning strike on house; protects against induced surge from nearby strike.
Customer sales conversation
Discovery:
- "Have you ever had appliances die after a storm OR power outage?"
- "How much sensitive electronics do you have?"
- "What's your utility area's reliability?"
Value proposition:
- "Replaces components only need maintenance every 3 - 5 years."
- "Some homeowners insurance offers discounts."
Bundle with: panel upgrade, smart-home install, EV charger.
Truck stock
Whole-house surge protector (Square D HEPD, Eaton CHSPT, common residential), various smaller brands. Replacement test (most jurisdictions); voltage tester.
Annual inspection
Check indicator LED: green = good; red = replace.
After major outage / storm: inspect + test.
Customer awareness: educate customer on LED check (simple owner check).
Replacement: 3 - 7 years OR sooner if needed.
Codes
NEC 230.67 (2020 update): all new dwelling units must have surge protective device (SPD) for the entire residence at the service equipment. Type 1 OR Type 2 device per UL 1449.
Required as of 2020 code adoption (varies by state).
References
- NEC 230.67 (2020) (Surge Protective Devices)
- NEC 285 (Surge-Protective Devices)
- UL 1449 (Standard for Surge Protective Devices)
- IEEE C62 series (surge protection standards)
- Manufacturer technical data (Square D, Eaton, Siemens, Intermatic)
- Manuall internal: Breaker + Panel Reference, Common Codes Overview