15Jan
EV Chargers in SF Garages: Load Calculations in Small Panels
Want Level 2 charging but only have a 100A service (or a packed subpanel)? The good news: there are usually options—if you start with the load calculation.
Step 1: Assess what you already run
- Key questions:
- What’s your main service size (often 100A in older homes)?
- Do you have electric heat, dryer, range, water heater?
- Any new planned loads (heat pump, induction, ADU)?
Step 2: Choose your Level 2 path
- Common approaches:
- Standard Level 2 circuit (fastest charging, requires capacity)
- Lower-amperage Level 2 (still very useful overnight)
- Load management (charger adjusts based on home demand)
Step 3: When you actually need a panel upgrade
- No physical breaker space
- Service is undersized for present + future loads
- You want higher charging power without compromises
The best EV install isn’t the biggest breaker—it’s the one that charges reliably without pushing your panel to the edge.
Your roadmap is simple: start with an assessment and load calculation, prepare a permit set, plan any service changes with the utility, rewire circuit by circuit with AFCI/GFCI protection, upgrade and label the panel, then pass final inspection and keep a clear turnover packet for records and resale.
Step 4: Permits and coordination
In SF garages, details matter:
- Cable routing and wall penetrations
- Panel access and labeling
- Parking/neighbor coordination in tight lots
Maintenance cadence (simple but effective)
- Annually: quick check for flicker, buzzing, discoloration
- After remodels: confirm insulation clearance and ventilation
- Any dimming issues: test with an LED-rated dimmer before replacing fixtures
Not if you want modern safety and insurance comfort. We recommend de-energizing and abandoning after new circuits are live.
Not always. Phased work and temporary power plans can keep sections of the house livable.
We use strategic fishing, attic and basement access, and patch-ready holes to reduce disruption.
