Adding a 40 Amp Circuit - Formulating a Plan

I would like to add a 40 amp circuit; intent is to charge an EV (Electric Vehicle) in my garage (50 feet from box). In the garage will be a ClipperCreek charger (HCS-40P, 32-amp) plugged into a 240V receptacle (NEMA 14-50). The design limit on the current EV is 13.3 amps, but I’m going heavy in anticipation of a future EV upgrade. I’m planning to use 8-3 cable. My condo was built in 1989 (FYI).

Please provide some input on the selected cable size. Should I go to 6-3?

Before I call the electrician, I would like to secure a general buy-in to my plan on the forum. Anything I’m missing?
Thanks,
TheKingfish

 

You are good with 8-3 for 40A circuit. If it's just 240V you can use 8-2. Does it need 120V?

 

A 14-50R receptacle is a 125/250 volt 4-wire receptaqcle, not 240 volt. Is this an attached or detached garage?

 

Thanks for your feedback. Not sure what pattenp means by – Does it need 120V? My plan is to install this new circuit next to an existing 120V.

The CC charger has optional plugs (14-50 or 6-50). Added research on my part show those are 4 & 3 wire respectively (I’m learning). Which way should I go?

The two-car garage is fairly small and attached. A separate source floated a 100A subpanel, although I don’t envision any more expansion. Are you thinking I may need a subpanel?

Yet another recent source says more and more vehicles will accept 40A chargers, which require 50A circuits. He says to run the 6 Awg and use a 40A breaker for now. If the new car needs a faster charger, there would be no need to re-pull the cable; just change the breaker.
Thanks,
TheKingfish

 

This isn't answering your question, but I would do some research on what your state or the federal government offers in rebates or tax credits when installing charging stations, even in your home. Hopefully you will be pleasantly surprised. In California this type of upgrade is encouraged.

As far as the cable, you can expect the system to require a neutral, so it makes sense to run at least a 8/3 with ground. You can run a 6/3 with ground for insurance, but there are very few garages (around here) with #6 cable installed and just the fact you are charging on a 240V system should be good enough without upgrades.

 

It depends on the voltage required for the charger. The 14-50 plug is 4 wires (2 hot wires, 1 neutral wire and 1 ground wire) for a 120/240 volt requirement. If the charger only needs 240 volts you can use the 6-50 3 wire plug (2 hot wires and 1 ground wire). I don't see any way they could give you the option of either a 3 or 4 wire connection unless you are getting maybe something less in the way of a charger with the 3 wire option.

That sounds like a reasonable plan to me. You could always upgrade the breaker up to 60 amps. You still have the other question though, a 3 wire or a 4 wire circuit (6-2 versus 6-3).

 

The charger HCS-40P charger is rated at 32A. The accompanying supply circuit spec states 240V, 50A. One model comes with the 6-50 plug; a second model with the 14-50 plug.

From that I presume I would need the 50A breaker. Your description links the 14-50 to 120/240V and the 6-50 to 240V only. Is that to say I could alternately run the 14-50 plug model at 120V? If so, that would seem to allow the trickle charge or the fast charge, although I’m not sure how that would be dictated (vehicle setting?). Given what I’ve outlined, I’m a bit confused as to which model would serve me best.

However, a second source suggests the 14-50 has a lot more uses than a 6-50 – see below for that full verbiage. I would appreciate your overall thoughts.

As to cable size, I guess I’d go with the 6 Awg if I can get it. Electrical is not my strong suit, so many thanks for your patience.
Thanks,
TheKingfish


As long as you pull a 4 wire connection, H,H,N,G, you can use either receptacle and save pulling wires in the future. As your currently selected charger doesn't need the neutral, you just fold back the white if using the 6-50.
Personally, I would go with the 14-50 and connect all 4 wires in the receptacle. The plug on the charger will not have the neutral pin connected. If some charger in the future needs the 120/240 connection it would be ready to go. If you ever have a short term use for that 120/240 connection, you can unplug the charger and plug in the other use. The 14-50 has a lot more uses than a 6-50.

 

No, the company offers the different plugs on the chargers simply for convenience if the buyer already has a 50A plug in their garage they want to use. The units are identical except for the different plugs.

A 50A circuit and receptacle are required in this case because NEMA standards only define a 30A and a 50A receptacle. This charger requires 32A minimum, which is greater than the capability of a 30A plug so we have to go up to 50A. If you bought the hardwired version of the 32A charger which does not utilize a cord-and-plug, but instead is connected directly to the building wiring, a 40A circuit would be acceptable (32A charger * 125% = 40A).

For maximum flexibility, install a NEMA 14-50R receptacle powered by 6-3/g cable from a double-pole 50A breaker. Buy the plug-in version of the charger with a matching 14-50 plug. This plug could also be used for tools like a welder or a cooking range if you ever think you'll need something like that in your garage.

For minimum expense, purchase the hardwired 32A charger and power it by running an 8-2/g cable from a double-pole 40A breaker to a junction box next to the charger. Run the flexible conduit whip from the charger to a knock-out in the junction box, connect the charger wires to the NM cable wires using big blue wire nuts.

 

Ben,
Your informative reply is about as good as it gets on a forum! I am sold on your NEMA 14-50R receptacle max-flexibility option and will pursue that path. A 50-foot roll of 6-3/g cable looks to be about $100 and the fruitful start of a well-planned project with my electrician.
Thanks,
TheKingfish