208Y/120 or 480Y/277? It depends on the loads.
Choosing 3-phase voltage class is a one-time decision at service installation — and the wrong choice creates expensive workarounds for years. Here's the decision logic.
By Steven Lockhart · Reviewed by Alex Towery, C-10 #989290
Updated 2026-06-16
208Y/120 service provides 120V phase-to-neutral (standard outlets and lighting) and 208V phase-to-phase (smaller motors, some HVAC, some commercial kitchen equipment). 480Y/277 provides 277V phase-to-neutral (commercial fluorescent/LED lighting at higher voltage) and 480V phase-to-phase (larger motors, industrial HVAC, manufacturing equipment). For Marin commercial buildings under 10,000 sq ft serving office/retail/restaurant: 208Y/120 is typically correct. For industrial-leaning, larger HVAC plant, or manufacturing: 480Y/277.
01How the voltage difference plays out in practice.
208Y/120 means most equipment in the building runs on 120V (matching residential outlets/lighting standards) or 208V (commercial kitchen equipment, smaller HVAC, certain motors). Equipment selection is broader because 120V/208V equipment is mass-market. Wire sizing is moderate (higher amperage for given wattage means larger conductors). Total cost-of-ownership for typical office/retail/restaurant typically favors 208Y/120.
480Y/277 means lighting runs at 277V (using less amperage for same wattage, thinner branch circuit wiring), motors run at 480V (lower amperage, smaller conductors for given motor size), and equipment selection narrows to commercial/industrial-rated gear. Wire sizing is favorable for larger loads (smaller conductors mean lower install cost on big runs). Total cost-of-ownership for industrial, large warehouses, or motor-heavy applications favors 480Y/277.
02Decision criteria by building type.
Office, retail, small restaurant — 208Y/120
General office equipment, retail lighting and outlets, small restaurant kitchen equipment all run on 120V or 208V. Mass-market equipment availability. 208Y/120 is the right choice in 80%+ of small/medium Marin commercial.
Large kitchen, industrial HVAC, manufacturing — 480Y/277
Commercial kitchens with multiple large gas/electric appliances often benefit from 480V on the equipment side (lower amperage). Industrial HVAC chillers and rooftop units commonly require 480V. Manufacturing equipment universally specified for 480V.
Mixed-use — 208Y/120 with step-up if needed
For buildings with mostly 208Y/120 needs plus occasional 480V equipment, install 208Y/120 service with a step-up transformer for the 480V equipment. Lower service-entrance cost; equipment-specific transformers add modest cost where actually needed.
03Why getting this right at the start matters.
The voltage decision happens at PG&E service installation. Changing voltage class later requires PG&E service replacement plus new transformer plus new panel — typically $30,000-$80,000+ for the change alone, not counting equipment compatibility. Buildings forced to retrofit voltage class typically do so because original sizing was wrong for actual operations.
For new construction or major service upgrades, the voltage discussion happens during initial planning with electrical engineer and us. We ask about: current equipment list, planned equipment over next 5-10 years, lighting strategy, building electrical load curve, expansion potential. Right answer emerges from operational specifics, not from default preferences.
Common questions.
Can I have both voltages in my building?
Yes — many commercial buildings run a primary voltage class with step-up or step-down transformers for specific equipment needing the other voltage. A 208Y/120 building with a 50 kVA step-up transformer for a single 480V industrial chiller is common. Adds complexity but provides flexibility. Discussed during engineering phase.
How do I know what voltage I currently have?
Check the meter or main service entrance — the meter typically labels voltage class. Or check your PG&E bill — commercial bills specify service class and voltage. Or visually inspect the main panel — main breaker rating and panel label usually identify voltage class. We confirm during quote inspection.
Does voltage class affect electricity cost?
Marginally. PG&E commercial rates depend on rate schedule (B-1, B-6, B-10, B-19, etc.) more than voltage class per se. Larger services on higher voltage typically qualify for different rate schedules with better demand charges. Net effect on operating cost varies by usage pattern; consultation with PG&E commercial rep during planning identifies the right rate schedule for your operations.
What if my equipment needs change?
Modest changes (adding equipment compatible with existing voltage) are easy. Major changes (shifting to equipment requiring different voltage) become expensive. The voltage decision should anticipate likely 5-10 year equipment evolution. We discuss this during planning for new construction or major upgrades.
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.