Installing Two EV Chargers With Load Sharing
Two EV chargers can be installed in one home by giving each its own circuit and using load sharing, also called power sharing or an EV energy management system, so both cars charge without overloading the panel. The electrician runs a load calculation first to confirm what the service can carry.
A second electric vehicle changes the math. Two chargers at full power can pull more than many older panels can supply once the AC is running. Load sharing solves that without a service upgrade in many homes. This page explains the options, how a two-car garage is wired, and how we decide what your panel can support.
Can I install two EV chargers in the same house?
Yes, two EV chargers can be installed in the same house, either as two separate units or one dual charger. Each needs a correctly sized circuit, and the electrician confirms through a load calculation that the panel can supply both, usually with load sharing or a panel upgrade if it cannot.
People often start by asking whether the panel can take two big breakers. The answer is about total load, not breaker count. A home with a large AC system, an electric range and a pool pump uses a lot of the service capacity, and each charger adds a continuous load for hours at a time.
The usual searches are along the lines of cost of installing two chargers and whether two single port chargers can be installed. They can. We look at your garage, your panel and how your household drives to recommend one of a few designs, then put it in a written quote.
What is load sharing for two EV chargers?
Load sharing, also called power sharing, lets two chargers divide a fixed amount of power between them. When both cars are plugged in, each charger gets part of the available current, and when only one is charging it can use more, so the combined draw stays inside the circuit's limit.
With load sharing, two chargers can be fed from a single circuit instead of two full size circuits. The chargers communicate with each other and adjust their output on their own. This reduces the wire, the breaker space and the demand on the panel.
Tesla Wall Connector units support power sharing between multiple units, and other brands offer similar features or dual port models. Chargers from different brands usually cannot share with each other, so the choice of hardware comes first. We install the chargers you buy, so check the load sharing feature before purchase.
What is an EVEMS and when do I need one?
An EVEMS, or electric vehicle energy management system, is a device that monitors the panel's load and limits EV charging so the total never exceeds the service capacity. You need one when the panel cannot support full speed charging for both cars plus the rest of the house.
An EVEMS can be a standalone controller with a current sensor on the service, or a feature built into the charger. Some electrical codes allow the load calculation to use the limited setting, so a smaller service can carry a larger charger. The authority having jurisdiction decides what it accepts, so we confirm with the city or county.
In practice it works like a referee. When the AC kicks on and household demand rises, the charging current drops for a while, and it rises again when demand falls. The car still reaches its charge, it just takes a flexible amount of time. For many overnight chargers that tradeoff is invisible.
How are two chargers wired in a two-car garage?
A two-car garage can be wired with two dedicated 240 volt circuits, one for each charger, or with a single shared circuit feeding two power sharing chargers or one dual-port unit. The right layout depends on the panel's capacity, the distance from the panel and where each car parks.
Two dedicated circuits give the most flexibility, with each charger running at its full amperage, but they need two breaker spaces and use the most panel capacity. A shared circuit uses less capacity and fewer spaces. Dual head chargers combine two connectors in one housing, which is a neat answer for a single wall.
We also plan for how cars actually park. The charge port may be on opposite sides, and cable reach matters. Placing the chargers on opposite walls, or centered on the wall between bays, can let each cable reach either car. We mark the spots on site before drilling anything.
Will my panel handle two EV chargers?
Whether a panel can handle two EV chargers depends on the service size and existing loads, and the electrician finds out with a load calculation. Many 100 amp panels cannot support two full speed chargers, while 200 amp panels often can, especially with load sharing.
The load calculation follows the National Electrical Code. We add up the AC, the water heater, the range, the dryer and other large loads, apply the rules, and see what capacity is left. Older Arizona homes with 100 amp service are commonly tight because of the AC.
If there is not enough capacity, there is a ladder of fixes. Load management lowers the effective demand. A subpanel adds spaces but not capacity. A panel upgrade increases capacity at the panel. A service upgrade, which can involve the utility, increases what the home can draw. We explain which one applies in writing. See our EV charger panel upgrade page.
What size breaker do two EV chargers need?
Each charger needs a breaker sized at one and a quarter times its charging amps, so a 32 amp charger uses a 40 amp breaker and a 40 amp charger uses a 50 amp breaker. A shared circuit for two power sharing chargers is sized for the combined limit that the chargers are set to.
The breaker size drives the wire size. Copper conductors are chosen for the amperage, the distance and the conditions, and the electrician sizes them to the code. Longer runs may need a larger wire to avoid voltage drop.
Many chargers can be dialed down to a lower amperage in their settings. Setting both chargers to 32 amps instead of 48 may cut the circuit size, and the car gains plenty of range overnight. We can set the output to suit your driving. See our breaker and wire size guide for the numbers.
Do both chargers need separate permits and inspections?
Two chargers installed at the same time are normally covered under one electrical permit and one inspection, as long as the work is done together. Adding the second charger later usually needs a new permit, because it adds a circuit and changes the panel's load.
The city or county building department sets the rules, and requirements can differ across Glendale, Peoria, Surprise and the unincorporated areas, so we confirm with the right office. A licensed contractor normally pulls the permit and is responsible for the work.
If you think a second car is coming, tell us now. We can run conduit sized for two circuits, leave a labeled space in the panel and do the load calculation for both, which saves opening walls twice. It costs less in labor to prepare the route once than to redo it later.
What to Expect
- Panel size and main breaker rating
- List of big loads: AC, pool, range, dryer, water heater
- Which two charger models you plan to buy
- Where each car parks and where its charge port sits
- Whether you want a shared circuit or two circuits
- Written quote that includes the load calculation and permit
Related Questions, Answered
All EV charger services: EV Charger Installation hub · EV charger service page
Frequently Asked Questions
Is a dual-port charger better than two single chargers?
A dual-port charger is neater and often cheaper to wire, because it uses one mounting spot and one feed, while two single chargers give more placement flexibility. The better pick depends on your garage layout and panel capacity. We install either type, and the choice usually comes down to cable reach.
Can two different brand chargers share power?
Generally no, because load sharing relies on the chargers communicating, and that works within one brand or product family. Mixed brands can still run together with an energy management system that limits the total at the panel. Ask us before buying so the hardware works together.
Does load sharing make my cars charge slower?
Only when both cars are plugged in and the home is near its limit. If one car is charging, it can use the full available power. Overnight, most cars finish with hours to spare even at reduced speed, so most drivers never notice the difference.
Can I add the second charger a year after the first?
Yes, a second charger can be added later if the panel has capacity or if load management is used. The best way is to plan for it at the first install, with spare conduit and a load calculation for both chargers, which avoids rework and saves labor on the second visit.
Do two chargers affect my electric bill differently than one?
They add energy use based on how many miles you drive, not on the number of chargers. Two cars use roughly twice the charging energy of one. Rate plans change, so check current terms with your utility, APS or SRP, for time of use options that favor overnight charging.
EV Charger Installation
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