Glossary

Electrical glossary. The homeowner's reference.

Plain-language definitions for the terms you'll meet in quotes, inspection reports, and our guides — written and reviewed by our licensed C-10 electrician. Every term links to the pages where it matters.

02·All terms · 63 terms

Every term, A to Z.

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20-Year Workmanship GuaranteeSunrise's workmanship guarantee covers our installation labor — the quality of how we do the work — for 20 years from the date of completion. If a connection we made fails, a wire we ran develops a fault from installation error, or a panel we installed has a defect attributable to our workmanship, we come back and fix it at no charge.

A

AFCI — Arc Fault Circuit InterrupterAn AFCI is a special type of circuit breaker that detects the electrical signature of arcing — the tiny sparks that happen when a wire is damaged, a connection is loose, or insulation fails. Normal breakers only trip on overload (too much current) or short circuit (direct fault). AFCIs trip on patterns that indicate an arc fault, which is the cause of most residential electrical fires.
AHJ — Authority Having JurisdictionThe AHJ is the local government office that issues building permits and inspects work. For most electrical work in Santa Cruz County, the AHJ is either the county building department (for unincorporated areas) or the city building department (for work inside city limits — Santa Cruz, Capitola, Scotts Valley, Watsonville).
AHRI — Air-Conditioning, Heating, and Refrigeration InstituteAHRI is the industry trade association that certifies the performance of HVAC equipment. AHRI testing verifies a manufacturer's claimed efficiency ratings (SEER2, HSPF2, UEF for water heaters, etc.) against standardized test conditions, producing an AHRI certificate that documents the certified ratings for a specific equipment configuration (indoor unit + outdoor unit combination).
ATS — Automatic Transfer SwitchAn Automatic Transfer Switch is the device that detects when grid power has gone out and automatically switches your home's electrical load from the grid to your backup power source (a standby generator or a battery system). When grid power returns, it switches back. Without an ATS, you have a manual transfer switch — meaning you have to physically flip the switch yourself when the grid goes down.
Amperes (Amps, A)An ampere — usually just called an "amp" — is the unit of electrical current. Current is the rate at which electrons flow through a wire. The more amps a circuit can carry safely, the more simultaneous load it can support.

C

C-10 — Electrical Contractor LicenseC-10 is the California Contractors State License Board classification for Electrical Contractors. It authorizes work involving the installation, maintenance, and repair of electrical wiring, conduit, panels, service entrances, and most fixed electrical infrastructure in residential and commercial buildings. Sunrise holds a C-10 license (license # C10-1097237).
C-20 — Warm-Air Heating, Ventilating, and Air-Conditioning LicenseC-20 is the California Contractors State License Board classification for HVAC contractors — Warm-Air Heating, Ventilating, and Air-Conditioning. It authorizes work involving the installation, repair, and maintenance of heating and cooling systems including furnaces, air conditioners, heat pumps, ductwork, and associated mechanical equipment.
C-46 — Solar LicenseC-46 is the California Contractors State License Board classification for Solar contractors. It authorizes work involving the installation of solar energy systems — photovoltaic arrays, solar thermal systems, mounting hardware, and the system-level electrical interconnection.
CEC — California Electrical CodeThe CEC is California's version of the National Electrical Code. California adopts the NEC every three years and adds amendments specific to California — earthquakes, wildfire risk, energy efficiency, solar mandates, and other state-specific concerns. The current edition is the 2025 CEC, which builds on the 2023 NEC with California-specific changes.
CEE Tier 2 — Consortium for Energy Efficiency Tier 2CEE Tier 2 is the efficiency rating tier defined by the Consortium for Energy Efficiency, which sets benchmarks above ENERGY STAR for HVAC equipment. The IRS uses CEE Tier 2 thresholds as the qualifying efficiency benchmark for Section 25C federal tax credit eligibility on heat pumps.
CSLB — California Contractors State License BoardThe CSLB is California's regulatory body for construction contractors. It licenses contractors, defines what work each license classification authorizes, enforces standards, and investigates consumer complaints.
Combination Meter MainIn California, the standard residential service entrance configuration is a "combination meter main" — a single enclosure mounted on the outside of the home that contains the PG&E meter, the main service disconnect breaker, AND the panel that distributes power to individual circuits. Everything in one box on the exterior wall.
Continuous Load + 125% RuleThe NEC defines a "continuous load" as any load expected to run for 3 hours or longer. Examples: EV chargers, electric heat strips, motors running continuously, HVAC blower fans. The corresponding sizing rule (NEC 210.19, 215.2, 230.42): circuits and equipment serving continuous loads must be sized at 125% of the continuous load.
Critical Loads PanelA critical loads panel is a separate sub-panel that contains only the circuits you want backed up during an outage — typically refrigerator, well pump, key lighting, internet/router, garage door opener, maybe a freezer and a charging outlet. The critical loads panel is fed by the backup power source; everything else stays on the main panel and goes dark during an outage.

D

Dedicated CircuitA dedicated circuit is one that serves a single high-power appliance or specific load, rather than a shared circuit serving multiple outlets across a room. Each dedicated circuit gets its own breaker in the main panel, its own dedicated wire run, and its own outlet (or hardwired connection) at the appliance.
Demand FactorDemand factor is the NEC's recognition that not all electrical loads run simultaneously at full capacity. If you have a 50A range, a 30A dryer, a 30A water heater, a 5-ton AC, and 12 lighting circuits, the sum of their nameplate ratings is much higher than the maximum load your panel actually sees at any one moment — because nobody runs all of them at peak simultaneously.
Dwelling Load Calculation (CEC Article 220, Part III)The dwelling load calculation is the math that decides whether your existing service can carry a new load — a heat pump, an EV charger, an induction range — or whether the service has to be upgraded first. Article 220, Part III of the California Electrical Code sets out the standard method for running it.

E

E-TOU-C — PG&E Standard Residential TOU RateE-TOU-C is PG&E's default time-of-use rate plan for residential customers. Peak hours are typically 4pm-9pm weekdays (when demand is highest). Off-peak is everything else. Lower differential between peak and off-peak than EV-2A, but no EV-specific assumption baked in.
EV Charging Levels (Level 1, Level 2, Level 3)EV charging is categorized by speed, which corresponds to voltage and circuit type:
EV-2A — PG&E EV Time-of-Use RateEV-2A is PG&E's time-of-use rate plan specifically designed for residential customers who own an electric vehicle. The defining feature: significantly lower off-peak rates (typically midnight-3pm in 2026) than the standard residential TOU rates, in exchange for higher peak-hour rates (typically 4pm-9pm).

F

Federal Pacific Electric (FPE) PanelFederal Pacific Electric (FPE) was a panel manufacturer that sold widely in U.S. homes built from the 1950s to the early 1980s. The brand was associated with a specific breaker design called Stab-Lok. Independent testing in the 1980s and a 2002 Consumer Product Safety Commission inquiry found that FPE Stab-Lok breakers fail to trip under overload conditions at rates dramatically higher than other manufacturers — meaning a circuit that should shut off during a fault can stay live and start a fire instead.
Final InspectionThe final inspection is the AHJ inspector's on-site visit at the end of an electrical job to verify the work was completed per the permit, meets current code, and is safe. When the inspector signs off, the permit closes and the work is officially complete from the AHJ's perspective.
Free Whole-Home Electrical InspectionSunrise's free whole-home electrical inspection is a no-cost, no-obligation 1-2 hour on-site visit by one of our licensed techs. We walk your home, examine your panel, sample your outlets and switches, look at your service entrance, identify anything that's hazardous, anything that's noncompliant with current code, and anything that's just inefficient (old fluorescents, undersized circuits, etc.).

G

GFCI — Ground Fault Circuit InterrupterA GFCI is a safety device that monitors the electrical current flowing on a circuit's hot and neutral wires. When those currents don't match — which happens when current is leaking through a path other than the intended circuit (like through a person who's just touched live wire while standing in water) — the GFCI shuts the circuit off within milliseconds. It's designed specifically to prevent electrocution.
GoGreen Home — California energy financing programGoGreen Home Energy Financing is California's state-backed loan program for residential energy work. Administered by CAEATFA (California Alternative Energy and Advanced Transportation Financing Authority) and delivered through participating community lenders. Sunrise's primary lending partner is **Matadors Community Credit Union** for most Santa Cruz County customers.
Grounding + BondingGrounding and bonding are the two related safety systems that protect you from electrical shock and protect equipment from fault currents. **Grounding** connects the electrical system to the earth (literal earth, via ground rods, plates, or the metal water service pipe). **Bonding** connects all metal parts that could become energized in a fault (panels, conduits, junction boxes, gas piping, water piping) to each other and to the grounded conductor.

H

HFTD — High Fire-Threat DistrictHFTD is the CPUC-adopted designation for areas in California with elevated wildfire risk based on fuel, weather, terrain, and ignition history. The map has three tiers: Tier 1 (lowest), Tier 2 (elevated), Tier 3 (extreme). PSPS shutoffs primarily affect Tier 2 and Tier 3 zones. Building code requirements for fire-resistant exterior assemblies (CBC Chapter 7A) also key off HFTD designation.
HPWH — Heat Pump Water HeaterA heat pump water heater is a water heater that uses a heat pump (same technology as ASHP HVAC) to move heat from the surrounding air into the water tank. Roughly 3× more efficient than electric resistance water heating, and significantly more efficient than gas water heating once you account for the gas combustion losses.
HSPF2 — Heating Seasonal Performance Factor v2HSPF2 is the standardized measure of a heat pump's heating efficiency over a typical heating season. Higher HSPF2 = more heat output per unit of electricity consumed. The "2" version (effective 2023) replaced the older HSPF metric with revised test conditions.
Heat Pump (HVAC)A heat pump is an electric heating + cooling system that moves heat instead of generating it. In cooling mode it works like an air conditioner (move heat out of the house). In heating mode it reverses (move heat from outside air into the house). Modern cold-climate heat pumps work efficiently down to ~5°F, well below anything Santa Cruz County sees.

I

IRA — Inflation Reduction ActThe Inflation Reduction Act is the federal law signed into effect August 2022 that significantly expanded U.S. clean-energy tax credits, including the residential Section 25D (solar + battery), the residential Section 25C (heat pumps + electrification), and several commercial-side credits including Section 48E (commercial investment tax credit).
ITC — Investment Tax CreditITC is the catchall industry term for the federal tax credits historically available for renewable energy investments. "ITC" most often refers to the commercial-side investment tax credit (now Section 48E for projects placed in service after the IRA), but in casual industry usage it sometimes refers to the residential Section 25D credit too.
Induction RangeAn induction range uses electromagnetic fields to heat ferrous (iron-containing) cookware directly. Pots and pans heat up; the cooktop itself stays cool except where heat radiates back from the cookware. More efficient and significantly faster to heat than gas or electric resistance ranges. Comparable to gas in responsiveness; ~85% energy-efficient vs gas at ~40% (because gas loses most of its energy to the air around the pan).

K

K&T — Knob and Tube WiringKnob and tube is the wiring method used in U.S. residential construction from roughly 1880 through the early 1940s. Single conductors (one hot, one neutral) run separately through air, supported by ceramic knobs at structural members and ceramic tubes where they pass through joists or studs. No grounding conductor. No protective sheathing. Insulation is rubber or cloth, both of which become brittle with age.
Kilowatt-Hours (kWh)A kilowatt-hour (kWh) is the unit PG&E uses to bill you for electricity. It measures energy used over time: one kilowatt (1,000 watts) of power consumed for one hour. A 100W lightbulb running for 10 hours uses 1 kWh. An EV battery charging at 7 kW for one hour uses 7 kWh.

L

Like-for-Like Panel ReplacementThe 2026 PG&E Greenbook revision introduced a "like-for-like" rule for residential panel replacements. If a new panel matches the OLD panel in: amperage rating (e.g., 200A → 200A), physical location (same exterior wall, same height, same enclosure size), and service-entrance configuration (combination meter main → combination meter main), THEN the replacement can be completed without a full service-entrance re-inspection by PG&E.

M

Main Panel (Service Panel)The main panel is where the electrical service from PG&E's grid enters your home and gets distributed to the individual circuits powering your outlets, lights, and appliances. The main breaker — the biggest switch at the top of the panel — is the master shutoff for the entire house. Below it, individual circuit breakers protect each circuit from overload.
Manual J — Residential Load CalculationManual J is the residential load calculation standard published by the Air Conditioning Contractors of America (ACCA). It's what HVAC contractors use to determine the correct heat pump or HVAC system size for a given home — based on square footage, insulation, window count and orientation, climate zone, ductwork condition, and occupant load.

N

NACS — North American Charging StandardNACS is the EV charging connector design Tesla developed and used exclusively until 2022, then opened to industry. Standardized as SAE J3400 in 2023. Compared to the prior J1772 (AC Level 1/2) + CCS1 (DC fast charge) two-connector system, NACS uses ONE connector for both AC home charging and DC fast charging, in a smaller, lighter form factor.
NEC — National Electrical CodeThe NEC is the national standard for safe electrical installation in the United States. It's developed by the National Fire Protection Association (NFPA) and updated every three years. The newest published edition is the 2026 NEC — but California doesn't use the NEC directly. It adopts an amended version on its own cycle (see CEC); the code in force in California today is the 2025 CEC, based on the 2023 NEC.
NEM 3.0 — Net Billing TariffNEM 3.0 is California's current solar export compensation rule, technically called the Net Billing Tariff (NBT). It governs what your utility pays you for solar power you send back to the grid. Adopted by the California Public Utilities Commission (CPUC) under Decision D.22-12-056 in December 2022, it took effect for new solar interconnection applications on April 15, 2023.

O

OBBBA — One Big Beautiful Bill ActThe One Big Beautiful Bill Act is the federal budget reconciliation law signed in 2025 that, among many other things, modified the IRA's residential clean energy tax credits. The most consequential change for homeowners: it terminated Section 25D (the 30% residential solar + battery credit) for systems installed after December 31, 2025.

P

PG&E GreenbookThe PG&E Greenbook is Pacific Gas and Electric's published rulebook for how to connect to its electrical grid. It sets the requirements for the service entrance — where the meter goes, what kind of disconnect is allowed, how the conductors are sized, what clearances are required around the meter. The current edition is the 2026 Greenbook, published every year or two with revisions.
PPA — Power Purchase AgreementA Power Purchase Agreement is a financing arrangement where a solar installer or financing company owns the solar system on your roof, and you buy the power it produces at a contracted rate (typically lower than what you'd otherwise pay the utility). Terms usually run 20-25 years.
PSPS — Public Safety Power ShutoffPSPS is California's program authorizing utilities (primarily PG&E in our area) to proactively cut power during high-fire-risk weather. Started in 2018 under CPUC authorization (Resolution ESRB-8). Triggers include sustained winds >25 mph, gusts >45 mph, humidity below 20%, dry fuels, and CAL FIRE Red Flag Warnings — typically in combination.
Permit (Electrical)An electrical permit is a written authorization from the local building department (AHJ) that lets a contractor do specific electrical work on your home. Pulling the permit costs money, takes time (simple residential permits are often same- or next-day; more complex scopes take longer), and triggers an inspection by an AHJ inspector once the work is done.
Permit-ReadyA permit-ready quote includes everything needed to pull a permit and pass inspection for the work described. That includes: scope written in code-compliant terminology, materials specified to meet current CEC requirements, labor estimated for the actual work the inspector will check, and any required documentation (load calculations, electrical drawings if required by AHJ).

S

SEER2 — Seasonal Energy Efficiency Ratio v2SEER2 is the standardized measure of an air conditioner or heat pump's cooling efficiency over a typical cooling season. Higher SEER2 = more cooling output per unit of electricity consumed. The "2" version (effective 2023) replaced the older SEER metric with revised test conditions that better reflect real-world installation conditions.
Section 25C — Energy Efficient Home Improvement Credit (EXPIRED 2025)Section 25C of the U.S. Internal Revenue Code was the federal tax credit that paid back 30% of qualifying energy-efficiency home improvements, with annual caps. It covered heat pumps, heat pump water heaters, insulation, air sealing, and an electrical panel upgrade installed to support other qualifying equipment.
Section 25D — Residential Clean Energy Credit (EXPIRED 2025)Section 25D of the U.S. Internal Revenue Code was the federal tax credit that paid back 30% of what you spent on solar PV, battery storage (3 kWh+), solar water heaters, geothermal, and small wind systems. Expanded by the Inflation Reduction Act (IRA) of 2022 to include standalone batteries. Originally scheduled to remain at 30% through 2032.
Section 48E — Commercial Clean Electricity Investment CreditSection 48E is the commercial-side federal tax credit for clean electricity property investments. It's the surviving path for federal tax credit benefit on residential solar and battery installs in 2026 — but only via the leased / third-party agreement route, where the system owner (the installer or financing entity) claims the credit and passes the savings to you as lower monthly payments.
Self-ConsumptionSelf-consumption is the share of your solar production that you use directly in your home rather than exporting to the grid. Under NEM 3.0, every kWh you self-consume is worth significantly more than every kWh you export — because you avoid paying the retail rate (around $0.42/kWh in PG&E territory) instead of getting paid the much lower export rate (around $0.05–$0.08/kWh).
Service EntranceThe service entrance is the physical infrastructure that brings utility power from PG&E's lines into your home. In California, the standard configuration is a "combination meter main" — a single integrated enclosure that contains the meter socket, the main service disconnect, AND the primary distribution breakers, all in one outdoor cabinet mounted on an exterior wall. There is no separate "meter base" as a distinct box in California residential service — that's an older or out-of-region setup. The full service entrance stack, from the utility side down, is: service drop (overhead) or service lateral (underground) → weatherhead (cap at the top of an overhead mast) → rigid mast → service entrance conductors (the heavy wires from weatherhead down) → combination meter main → conductors from the CMM's distribution section out to branch circuits and any sub-panels → grounding electrode system (ground rods, water-main bond, grounding electrode conductor).
Smart PanelA smart panel is a circuit breaker panel with software-driven circuit-level monitoring and remote control. Common brands include Span and Lumin. You can see real-time power use per circuit from a phone app, turn individual circuits on or off remotely, and set up automation rules (e.g., "if grid power is out, automatically turn off the dryer and EV charger to preserve battery capacity for refrigerator and lights").
SubpanelA subpanel is a secondary breaker panel fed from the main service panel via a "feeder" circuit. Used to extend electrical service to a part of the house (detached garage, ADU, basement workshop, addition) without running every individual circuit back to the main panel. The subpanel has its own breakers but no main disconnect (the main disconnect at the service panel covers it).
Sylvania Panel (Zinsco-Sylvania)Sylvania is the brand name on many 1970s-era electrical panels that are, internally, Zinsco panels. GTE-Sylvania acquired Zinsco in 1973 and continued producing the same panel design under the Sylvania label for several more years. The name on the door changed; the aluminum bus design — and its failure mode — did not.

T

T&P Valve — Temperature and Pressure Relief ValveA T&P valve is the safety device on every water heater that releases water if the tank's internal temperature or pressure exceeds safe limits. Without one, a malfunctioning water heater could rupture or explode. T&P valves are required by code on every residential water heater.
TOU — Time-of-Use RatesTime-of-Use rates charge different prices for electricity depending on the hour of the day, day of the week, and sometimes the season. The idea is that grid demand isn't constant, so the price you pay shouldn't be either — peak hours cost more, off-peak hours cost less.
Tesla Wall ConnectorThe Tesla Wall Connector is Tesla's home charging hardware — hardwired Level 2 EVSE, output adjustable from 8A to 48A continuous. Maximum 48A continuous = 11.5 kW = roughly 44 miles of range per hour on a Model 3/Y. It comes in two versions: the standard Wall Connector (NACS connector only) and the Universal Wall Connector, the same unit with a built-in J1772 adapter — so it natively charges any EV sold in North America, Tesla or not, today and as more manufacturers move to NACS.
Two-Contractor CoordinationA two-contractor coordination is the typical structure of a heat pump install (or HPWH install) where two separately-licensed contractors work in parallel on different scopes of the same project. For a heat pump HVAC install:

V

Volts (V)A volt is the unit of electrical "pressure" — the force that pushes current through a circuit. In US residential service, two voltages matter: 120V for standard outlets (lamps, TVs, phone chargers, small appliances) and 240V for high-power devices (electric range, dryer, EV charger, water heater, central AC).

Z

Zinsco PanelZinsco was a Los Angeles-based panel manufacturer whose residential load centers were installed widely across the Western U.S. from the 1950s through the early 1980s. Like Federal Pacific (FPE), Zinsco was later identified as having significant reliability problems — but with a different mechanism. Zinsco's aluminum bus bar alloy is highly susceptible to oxidation; oxidation creates resistance, resistance creates heat, and the cycle can end with the breaker's clip physically welding to the bus. A welded breaker can't trip during an overload — and its handle can read OFF while the fused connection still conducts (the "false off" hazard).

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