Car Charging With an Electric Dryer Circuit
This is a photo of my in-laws circa 1969 service panel for their 2500 square foot house. Their service panel is maxed out and cannot accept a new 20 amp circuit. Overloading the bus could result burning the house down. They could upgrade the servce panel, but that would be expensive. There is another option, we could install a load transfer switch that would allow the supply circuit to direct current to either the dryer or the charging station, but not both concurrently. In this article I am going to offer a lower cost solution to this problem than changing out your service panel.
I visit my elderly mom a few times a month and I charge my electric car using a jimmy rigged adapter that allows me to plug a charging station into her dyer receptacle. My adapter is not to code, but it does work. Unfortunately, it is rather cumbersome in that I need to turn the circuit breaker off, pull out the dryer to access the outlet, pull the dryer plug, plug in the charging station, and energize the breaker. It is really a pain, and my wife is uncomfortable doing it. While my mom's service panel is rated at 200 amps and has capacity to install another circuit, the project would be exhausting as it is mounted at the opposite end of the house. This would require running a cable through two attics, and down the side of the house to the garage.
The service panel is to the far left and getting to the garage is quite a run through two attics.
As luck would have it, next to the garage is her laundry room, complete with an electric dryer circuit. The dryer outlet is 220 volts and wired for a 30 amp circuit. My plan is to install a double throw switch to allow the incoming dryer circuit to provide power to either the electric dryer, or an electric vehicle charging station, but not both at the same time. If I tried to feed both the dryer and charging station at the same time the circuit breaker would be overpowered. If the breaker does not respond in time, the wiring could be fried, and potentially burn down the house.
The key to making this work is to find an electric charging station that is designed to be powered by a dryer circuit. Fortunately, the ClipperCreek LCS-25P was designed to be powered by a 30amp circuit. At the time of the writing it is the only charging station out of the box that is designed for a 30 amp circuit. The charging station is compact, and well built. It also is designed to supply up to 20 amps of power to your car, slightly higher than the entry level 16amp units that are also available.
There are a handful of double throw switches on the market:
General Electric TC35322
General Electric TC70321 (Discontinued)
For my installation I went with the latter discontinued GE switch. This model hasn’t been manufactured in years, but I was able to find a new old stock one from eBay for $80. It is a sturdy, well built unit with a cast iron handle that feels comfortable, but not too hard to switch. If you are ordering a current model expect to spend $175 for the box. If you are trying to save some money look on eBay as sometimes there are some great deals. However, I suggest buying the charging station new from the manufacturer or authorized reseller so you can enjoy the warranty if you need to use it.
Inside my transfer switch. This one is fused, most are not. This is a nice quality switch rated at 30 amps.
For the build out I placed a square work box designed to fit over the outlet. I then used EMT tubing to carry wires from the switch to the original outlet. From there one set of wires went to the new car charging outlet, with the second set of wires running back to the original receptacle location. I also extended the ground wire to the switch box where I bonded it. I ran a ground wire to the new receptacle that powers the charging station. It is extremely important to properly ground all receptacles, boxes, and tubing associated with the installation.
Yes, that is a natural gas hookup by the baseboard. I gave up trying to convince my 81 year old mom to go with a gas dryer. She likes electric! If your house has dual hookup the easiest solution is just to get a new gas dryer and forego the transfer switch.
This is how it works. When the handle is in the down position it feeds electricity to the dryer. When the handle is in the upper position the system feeds electricity to the charging station. The center position does not feed either circuit. For safety considerations the box may only be opened when the lever is in the off position. However, the inside is still energized so it is advisable to put a lock on the door to prevent unsuspecting little ones from receiving a shock.
One nice feature of the LCS-25P is it comes standard with a 25 foot cable that allows its cable to reach the car from the laundry room.
If you are handy with electricity you should be able to build this out yourself. If you are unsure of some of the terms I have mentioned then I would take that as a hint that you should probably hire a qualified electrician to install this setup. My project took five hours to complete, not including a couple of trips to Home Depot to buy parts. I did half of it in the dark with a flashlight as coincidentally high winds blew a tree onto a nearby power line, blacking out the neighborhood. Not including the ClipperCreek station I invested about $200 into parts and wire to build it out..
Project completed! The compact ClipperCreek station stores out of the way until needed.