EV Emergency Preparedness Guide for San Francisco Households

An electric vehicle changes what an emergency looks like at your house. You no longer queue for fuel before a storm, but you cannot store a jerrycan of electrons either - your reserve is whatever state of charge is in the pack when the grid goes down. That single fact drives the entire plan: charge ahead of the event, know what your home equipment will and will not do when the power is out, and have a safe way to move the reserve back into the house if you need it. This guide is written for San Francisco households on PG&E service, where the realistic events are winter storm outages, Public Safety Power Shutoff events, and earthquakes.

Why your EV is one of your better emergency assets

A modern EV carries a 60-100 kWh battery - many times a home battery's capacity - and it can move. Three consequences are worth planning around:

• No fuel supply chain. During a regional outage, the bottlenecks are petrol stations without power and the queues around the ones that have it. A charged EV bypasses both.
• It can run things. Some vehicles offer vehicle-to-load: a 120 V outlet or an adapter that runs a fridge, a router, lights or a medical device from the traction battery. It is modest - typically 1.5 to 3.6 kW depending on the model - but it is enough to carry a household through a short outage.
• It can be your retreat. Heat or air conditioning, a safe place to sit, and enough range to reach an unaffected area if you have to leave.

The 48-hour rule: charge before the forecast turns

The single highest-value habit in this guide is charging ahead of the event rather than during it. Watch the National Weather Service forecast and PG&E's Public Safety Power Shutoff notices, both of which are published in advance of the events that actually cause multi-day outages here. When a storm, a high-wind red flag day or a shutoff window is announced:

• Charge to your normal daily target immediately, while the grid is still up.
• Raise the target for the duration of the alert. A pack held between roughly 60 and 80 percent covers most household needs and is still a comfortable storage band for the battery.
• Do not wait for the outage to start. Scheduled charging set for overnight off-peak is the right habit in normal weeks and the wrong one on the day a shutoff is announced - override it that day and say so out loud to anyone else who drives the car.
• Fill a second vehicle if you have one, and charge the smaller electronics, power banks and medical devices at the same time.

What actually happens to a home charger in an outage

Nothing dramatic, which is exactly why people misread it:

• The charger goes dark. A Level 2 unit is fed from your panel, so when the panel is dead the charger is dead. There is no reserve inside it and no way to make it work without a live source.
• Ground-fault protection may trip on restoration. When power returns, a moisture-laden connector or a marginal GFCI can trip. Reset once, and if it trips again, stop and treat it as a fault rather than a nuisance.
• Never back-feed the house through the charger. No adapter, no cable, no improvised connection between a generator and the charging circuit. Back-feeding a branch circuit that is not isolated energises wiring that a neighbour or a utility worker may be touching, and it bypasses every protective device the circuit has.
• A portable generator will not run a Level 2 charger. Throwing 40 continuous amps at a small generator is not a configuration that works; if you must charge during an outage and you have a generator sized for it, Level 1 charging on a properly isolated circuit is the realistic path.

Backup power without improvising

If you want the car's energy or a generator to serve the house, the connection has to be engineered. The legitimate options are a manual transfer switch or a generator interlock kit installed by a licensed electrician, a battery system with a critical-loads panel, or vehicle-to-load for individual appliances through the car's own outlet. Our escalation guide covers which of these need an electrician and which are simply a plug.

Earthquakes: the San Francisco-specific case

Storm prep is a charge-management problem; an earthquake is a safety problem. After significant shaking:

• Smell for gas first. If you smell gas, leave, and do not operate electrical equipment - including the charger - on the way out. Charge the car from a public station well away from the building instead.
• Do not re-energise a damaged circuit. Inspect the charger, its conduit, its mounting and the wall it is fixed to before turning the breaker back on. A unit that has been pulled off the wall by shaking has strain on the terminations behind it.
• Check for water before electricity. A burst pipe or sprinkler line interacting with a live 240 V circuit is the dangerous combination, not the damaged charger itself.
• Expect an inspection backlog. In a regional event, electricians and the city are triaging, so a charger that is dead but intact may wait. Your reserve charge is what carries you through that gap.

Evacuation readiness

• Keep the pack around 80-90 percent when an evacuation warning is plausible - not full every day, but high when it matters.
• Keep the mobile connector and your adapters in the car, including a J1772 or NACS adapter as appropriate to your vehicle, so any public AC station is usable.
• Watch the 12 V battery. It is the part that strands EVs, not the traction pack, and it fails quietly.
• Set the cabin preconditioning habit aside and prioritise range; where public DC fast charging is available on your route, know it in advance rather than finding it in traffic.
• Keep the go-bag list separate from the car list: documents, medications, water, phone power, and a printed note of your charging accounts in case the phone dies.

When the charger itself is the emergency

A fault that smells, smokes or trips repeatedly is a stop-now event, not an inconvenience to schedule next month. Turn the breaker off, leave it off, and call a licensed electrician. A charger that reports a fault code but stays cool, trips nothing and simply will not start is a different category - that is a warranty or support call to the manufacturer or the installer. If the charger failed because of water intrusion, storm debris or a power surge, photograph everything before anyone touches it, because that documentation is what supports an insurance or warranty claim.

After the outage: rebuild the plan

When power comes back, do not simply resume the old schedule. Test the charger deliberately, confirm the GFCI resets cleanly, verify the current limit is still where it should be, re-check any scheduled charging that the outage or a firmware retry may have disturbed, and note what actually ran out first. Every multi-day outage here teaches a specific lesson about your household's reserve - the number of days of driving a charge really represents, and which appliances matter most. That note is the plan.

Frequently Asked Questions