Sharing an A/C Circuit With an EV Charger: An Elkhart Lake Garage Install

In Elkhart Lake, we installed a Level 2 EV charger in a garage without running a new circuit from the panel: a SimpleSwitch load management device lets the charger share the home's existing air conditioner circuit. When the A/C needs power, the charger waits; when the A/C is off, the car charges.

Our crew finished this job on November 2, 2026. Here is what it involved and what to check if you are considering the same approach.

The job

The homeowner wanted a hardwired charger in the garage and had already bought the equipment: a ChargePoint Home Flex charger and a 50-amp SimpleSwitch. Instead of adding a new 240-volt circuit for the charger, the plan was to share the existing 30-amp air conditioner circuit between the A/C and the charger.

The scope written for the job laid out the steps:

• Inspect the existing 30-amp A/C circuit and verify the wire size, the breaker rating, and that the equipment was compatible.
• Install the SimpleSwitch and reconfigure the existing circuit to feed it, with separate outputs to the A/C disconnect and to the EV charger.
• Inspect the A/C disconnect and replace or modify it if needed.
• Mount the charger at the chosen spot on the garage wall, hardwire it, and set it to the highest charging amperage the existing circuit and equipment allow.
• Install the conduit and wiring needed to tie it all together.

Our crew completed the install on November 2. Photos from the finished job show the SimpleSwitch box on the garage wall, conduit running from it to the charger, and the charger mounted and hardwired.

What a SimpleSwitch actually does

SimpleSwitch's own product page describes it as an automatic load management device that balances power between two appliances. When the primary appliance is running, the secondary one, such as an EV charger, temporarily pauses. When the primary shuts off, power to the secondary comes back on its own.

The 50-amp installation manual adds the details that matter day to day:

• The priority appliance always gets uninterrupted power.
• The secondary appliance only gets power when the priority appliance is off or drawing less than 250 watts.
• There is a five-minute delay before power is restored to the secondary side.
• The device's fail-safe opens the secondary output if there is a power or internal board malfunction, cutting power to whatever is connected there.
• An EV charger on a SimpleSwitch must be set on the charger itself, not in the car, to a maximum of 48 amps, and the combined draw on the device cannot go above 50 amps.

So with an A/C and a charger sharing one circuit, the charger is the one that waits: charging pauses while the A/C runs and resumes a few minutes after it stops.

Why share a circuit at all?

The usual way to add a Level 2 charger is a new dedicated 240-volt circuit from the panel, sized to the charger. That is still the right answer in plenty of homes, and our EV charger installation page walks through how we approach it.

But a new circuit needs room in the panel and enough capacity to carry the load. When a panel is short on either, the choices get bigger: rearranging circuits, or a panel or service upgrade. A load management device like SimpleSwitch is another option in some homes because the charger uses capacity that is already there for a big appliance that doesn't run all the time.

What to check before you try this

This is not a fit for every house. The manufacturer says installation must be done by a licensed, qualified person following its instructions and local electrical codes. These things have to line up:

1. The existing circuit. On this job, the first step was checking the A/C circuit's wire size and breaker rating. Those set the ceiling on what the charger can be allowed to pull.
2. The charger's setting. A charger sharing a circuit has to be set at the charger to an amperage the circuit and the SimpleSwitch can carry. In this garage, configuring the charger to the highest safe amperage for the existing circuit was part of the job.
3. The other appliance. While it runs, the charger is paused.
4. The disconnect and wiring path. Here the A/C disconnect had to be inspected, and conduit and wiring were needed to reach the charger location.
5. Your panel. If you are weighing load sharing against a new circuit or an upgrade, it helps to know what your panel can carry first. Our Port Washington post on what a home needs before a Level 2 charger covers that side.

Thinking about an EV charger in Sheboygan County?

Elkhart Lake is one of the Sheboygan County communities we work in from our base in Random Lake. You can see more on our Sheboygan County page.

If you already have a charger picked out, or you are trying to figure out whether your panel can handle one, call us Monday through Friday, 8 to 4, or send a request through our contact page. Tell us what charger you have or want and where it would go, and we can talk through whether a dedicated circuit, load sharing, or a panel change makes sense.