1. [Home](/) 2. [Guides](/guides/) 3. EV chargers and backup generators at home # EV chargers and backup generators at home Both an EV charger and a backup generator put a heavy load on your home's electrical system. Here is how each one works, what your panel has to handle, and where the safety lines are. ## Key takeaways - Level 1 charging uses a standard outlet and is slow. Level 2 uses a 240-volt circuit and suits daily driving. - A charger is a continuous load, so its circuit is sized at 125 percent of the charger's draw, and the panel needs room for it. - A load calculation, not the label on the main breaker, tells you whether your panel can take a charger. - Never connect a generator to a house by plugging it into an outlet. A transfer switch or interlock is required. - Charger circuits, transfer switches and generator hookups are permitted work for a licensed electrician. ## Level 1 and Level 2 charging Every plug-in vehicle comes with a cord that runs from a standard 120-volt outlet. That is Level 1 charging. It is slow, adding only a handful of miles of range per hour, but it works for drivers who cover short distances and park overnight. The outlet should be on its own circuit, in good condition, and grounded. A worn receptacle, an ungrounded outlet in an old garage, or an extension cord is a real fire risk, because a vehicle draws a steady load for many hours. Level 2 charging uses 240 volts, the same kind of supply as an electric dryer or range. It is several times faster than Level 1, and an overnight session refills most daily driving with room to spare. Winter matters here. Cold weather cuts a vehicle's range and the battery uses energy to warm itself, so Southwest Ohio drivers often find that Level 1 keeps up in June and falls behind in January. A Level 2 charger is either wired directly to a dedicated circuit or plugged into a 240-volt receptacle. The circuit, location and permit details are covered in [installing a Level 2 EV charger at home](/guides/ev-and-generators-guide/level-2-charger-at-home/). ## Panel capacity and what a charger adds A charger is a continuous load. Electrical code treats anything that runs for three hours or more as continuous, so the circuit is sized with margin: the breaker is rated at 125 percent of the charger's draw. A charger that draws 32 amps needs a 40-amp breaker, and one that draws 40 amps needs a 50-amp breaker. The wire, the breaker and the charger all have to match. The bigger question is whether the panel can carry the charger on top of everything else in the house. That depends on whether the panel has open breaker spaces and whether the service has enough total capacity. Older homes in Southwest Ohio often have 100-amp service, and some still have fuse panels or panels with no spare spaces. Finished basements and additions over the years tend to use up whatever room there was. You cannot answer the capacity question by reading the label on the main breaker. An electrician does a load calculation, adding up the range, dryer, water heater, furnace or heat pump, air conditioning and the new charger using the methods the code allows. If the numbers work, the charger goes on its own circuit. If they are tight, there are options: a lower-amperage charger, a load management device that makes the charger back off when the dryer or oven is running, or a [panel upgrade](/services/panel-upgrades/). Opening a panel is a job for a licensed electrician. The conductors that feed the main breaker stay live even when the main is switched off. ## Permits and inspections Adding a 240-volt circuit is permitted work almost everywhere. Ohio's electrical rules follow the national electrical code, and permits and inspections are handled locally, usually by a city or county building department. Requirements vary from one jurisdiction to the next, so the electrician pulls the permit with the office that covers your address. The inspector checks the breaker size, wire size, grounding, connections and how the charger is mounted. An inspected circuit is one that someone other than the installer has looked at, and it avoids awkward questions with an insurer or a buyer when you sell the house. Generators follow the same pattern with more steps. A standby generator usually needs an electrical permit for the transfer switch and wiring, often a separate permit for the gas line, and it has to meet rules about how far the unit sits from windows, doors and property lines. A portable generator connected through an inlet or transfer switch needs a permit for that equipment too. Your electric utility may have its own requirements for generators and chargers, so it is worth asking early. ## Standby and portable generators A portable generator is a gasoline engine on a frame that you move into place when the power goes out. It costs less to buy, it can be stored away, and it can power a few essentials: a refrigerator, a sump pump, lights, the furnace blower. You have to start it, fuel it and run it outdoors, and it only works while you are home and awake to manage it. A standby generator is permanently installed outside, on a pad, and runs on natural gas or propane. When the utility power drops, an automatic transfer switch starts the generator and moves the house onto it within seconds. It also runs while you are away, which matters for sump pumps and freezers. It costs more up front and needs a gas supply, a permit and professional installation. Power outages in the region often come from summer thunderstorms, high winds and winter ice. A sump pump matters in many Southwest Ohio basements, where clay soil holds water and the pump may be all that stands between you and a wet basement. Think about what you cannot go without, then pick the type. The longer comparison is in [standby vs. portable generators](/guides/ev-and-generators-guide/standby-vs-portable-generators/). ## Transfer switches and why they matter A transfer switch is the safe connection between a generator and your house wiring. It makes sure your home is either on utility power or on generator power, never both. Without it, power from the generator can flow backward through your service and out onto the utility's lines. That is called backfeeding, and it can kill a line worker who believes the line is dead. It can also destroy the generator when utility power returns. There are three common arrangements. An automatic transfer switch goes with a standby generator and does everything on its own. A manual transfer switch is a small subpanel holding the circuits you want to back up, and you flip it over by hand. An interlock kit is a mechanical plate on your main panel that prevents the main breaker and the generator breaker from being on at the same time, usually paired with a weather-rated inlet on the outside wall. All three are electrician jobs. The wiring happens inside the panel, the switch has to be rated for your service, and the work is inspected. A generator installation done correctly gives you a way to run the house on a cord-free connection, with no extension cords through windows. ## Safety rules for every setup Carbon monoxide kills people during outages every year. Never run a generator in a garage, a basement, a crawl space or near a window, even with the door open. Keep it well away from the house, with the exhaust pointed away from doors, windows and vents, and follow the manufacturer's distance. Have working carbon monoxide alarms on every level of the home. Never plug a generator into a wall outlet with a cord that has a plug on both ends. It is the most dangerous shortcut in home electrical work, and it is the cause of backfeeding. If you want to power the house from a generator, use a transfer switch or an interlock. Let a portable generator cool before refueling, store gasoline in approved containers away from the house, and keep the unit dry. For chargers, do not use extension cords, power strips or adapters, and stop using any outlet that feels warm, smells hot or shows discoloration. Those are signs of a loose connection, and they call for [electrical repair](/services/electrical-repair/) before the next charge. ## Frequently asked questions Can I charge an EV from a regular outlet every day? You can if the outlet is grounded, in good condition, and on a circuit that is not shared with other heavy loads. Many garage outlets in older homes are not, so have an electrician check the receptacle and circuit first. Charging is slow, so this suits short daily trips better than long ones. Do I need a Level 2 charger? Not always. If you drive a short distance each day and are parked for many hours, Level 1 may be enough. If you drive more, own a larger battery, or want a margin for cold winter days, Level 2 is the more practical choice. Can a generator run an EV charger? A charger draws a large, steady load, and most generators sized for essentials cannot carry it along with the rest of the house. Most backup setups leave the charger off the backed-up circuits, or use load management so it only runs when there is spare capacity. Discuss it with your electrician before you size the generator. Do I need a permit to install a generator? In most places, yes. A standby generator typically needs an electrical permit and often a gas permit, and a transfer switch or inlet on a portable generator needs one too. Your electrician will know what your local building department requires. 6 min read. ### Want us to handle it? Radin Electric works in Hamilton, Fairfield, Oxford. [Get a quote](/contact/)[Call 513-827-4498](tel:+15138274498) ### In this guide - [Installing a Level 2 EV charger at home](/guides/ev-and-generators-guide/level-2-charger-at-home/) - [Standby vs. portable generators](/guides/ev-and-generators-guide/standby-vs-portable-generators/) ### Related services - [Panel Upgrades](/services/panel-upgrades/) ### Service areas - [Hamilton](/areas/hamilton/) - [Fairfield](/areas/fairfield/) - [Oxford](/areas/oxford/) ### Other guides - [Electrical panels and older home wiring](/guides/electrical-panel-guide/) - [Lighting, outlets and everyday electrical problems](/guides/home-lighting-guide/) ## Call 513-827-4498 or send a quote request and we will talk through your project. [Get a quote](/contact/) [Call 513-827-4498](tel:+15138274498) --- **Radin Electric** · 1329 Pater Ave, Hamilton, OH 45011 · 513-827-4498 · radinelectric@yahoo.com [Get a quote](/contact/) · [Services](/services/) · [Guides](/guides/) · [FAQ](/faq/)