GFCI right angle extension for Prime's included charging cable?

If you're only doing L1 charging, this should be fine. 15A is sufficient for the car.

 

Chances are that the outlet you're using is also rated at 15A. Also, the plug on the end of the EVSE cable is also NEMA 5-15 (15 A). When using any kind of extension/adapter, it's a good practice to check for loose/hot connections from time to time.

I'm curious what situation you have that requires a right angle adapter. Or are you just after the GFCI function?

 

If the garage is wired to code, the outlets will already be GFCI. Sometimes (not always) there can be flaky behavior when you have two GFCI's in series.You'll probably be OK, but I thought I'd let you know in case weird things happen.

Also, the manual says not to just let the EVSE just hang from the outlet as that can eventually loosen the wires. You'll want something to support the "brick" to relieve the tension. Some people use fancy holster-like pockets. I use a nail and just slide one of the holes in the brick over the nail at work. At home, there's a shelf next to the outlet so I hang a black rubber bungie on the shelf and hang the brick on the bungie. No weight on the plug that way.

 

And to carry that one step farther.......
If the garage outlet already HAS GFCI, you should be able to get a "heavy duty appliance" extension cord at any hardware store designed for 15 amps that will be cheaper than what you showed and likely will sit even closer to the wall.

 

Keep in mind that when you use an extension cord the intent of the EVSE plug temperature sensor (monitor house power receptacle) will be nullified. The connection which is now monitored is where the extension cord mates to the EVSE.

If desired, you can reduce the charging current to 8 amps to reduce the load on your home wiring. As long as the traction battery starts above 10%, it will charge to > 90% in about six hours. I’ve been using 8 amp mode since I normally charge the Prime between midnight and 6AM. There have only been a handful of times when the battery was less than 90% charged by the time I left for work.

 

Keep in mind that even with a two foot extension cord you’re still moving the EVSE temperature sensor monitor point to where the extension cord and EVSE mate. If the outlet where the extension cord plugs into gets hot (due to lousy connection to house wiring at screws outlet terminals, or outlet blades where extension cord plug and receptacle mate) the EVSE will not detect this.

 

i haven't had any problem with an extension cord over 10 years

 

Doesn’t mean someone else won’t.

 

true enough, but i think it one of those very very unlikely possibilities. always worth making sure the outlet is safe though

 

Whether you use the RA extension or not, it'll be hanging from the plug's strain relief unless you put it on a hook or something to bear the weight as recommended in the owner's manual.

This is a real possibility if you are neglectful and don't check the plugs every week or so so see if they are getting warmer than normal. I've been using extensions for years, but I check the temperature by feel towards the end of the charge almost every time I use one.

 

What role, if any, would the GCFI portion of the short extension play in mitigating the potential heat issue, say in a situation at a cottage where the outlet itself may not be GCFI? (I’m a historian, not an electrician.) Just curious because we rent a cottage (same one) every summer and I don’t know if the outside outlets are GCFI.

 

Buy an outlet tester if you want to check if an outlet is GFCI protected.
Klein Tools GFCI Receptacle Tester-RT210 - The Home Depot

The GFCI outlet will detect current to earth (ground) and current deltas between hot & neutral and trip if needed. Its purpose is not to detect an overheating outlet.

 

There are two separate issues. The Ground Fault Circuit Interrupter (GFCI) is electronics inside the "brick" of the Prime's charging cable. It is a device which measures the flow of current on the two conductors of the cable and watches to make sure that it is the same amount of current on both of them. The two conductors form a circuit where the current going in one conductor should be the same as that going out the other. If they do not balance, it means that some of that current is flowing through an improper path such as leaking water or, more seriously, a person. So, if the GFCI senses that imbalance, it shuts the circuit off instantly.

The over-heating risk is something else entirely. Because correctly installed wiring in your house will not overheat unless its rated current is exceeded -- and because the circuit breakers in you house are designed to shut down if too much current is being drawn through the wiring -- there should be little or no risk of over-heating. But the prongs on the plug of your charging cord and the outlet into which they are inserted are subject to corrosion and, in worn or damaged, failure to make a tight and firm connection, there can be over-heating at that point of connection even when drawing less current than would trip the circuit breaker to off.

From what I understand (and I have not actually taken apart one of the Prime's cords), there is a temperature sensor in the plug that either acts on its own or reports back to the electronics within the "brick." It it detects over-heating at the plug, it will shut down the connection between the car and the outlet, hopefully stopping the flow of current and the over-heating condition.

While GFCI devices are not unusual, this kind of thermal protection is an extra measure which Toyota most likely engineered to make the Prime's plug-in charging even safer and more idiot-proof.

As for your summer cottage, the best thing to do is to make sure that all of your house wiring, including outlets, is kept dry, undamaged and free of dirt or debris. A worn and corroded outlet with dirt and insects in its slots will not make a good connection and can overheat, so it's worthwhile to take a few minutes to inspect things when you return to your cottage after months of vacancy.

Of course, as a historian, you likely have learned from the remnants of the great civilizations that their decline can be traced directly to incomplete and improper maintenance.

 

I think the owners manual muddies the water of current fault protection a bit with mention of the EVSE’s CCID (charging circuit interrupting device). My understanding is this protects connection between the EVSE brick to the Prime from a fault condition.

My understanding is also that the EVSE does not have a GFCI integrated into it. Toyota would not need to recommend the outlet be a GFCI receptacle if this were the case. But if you think about it, it makes sense. The purpose of the GFCI is to disable the circuit once a fault is detected. This detection/disable point should be the outlet or directly plugged in at the outlet (such as a hair dryer with GFCI integrated plug). Say the integrated GFCI was inside the EVSE brick and you cut a portion of the cable between the brick and a non-GFCI outlet. If the circuit breaker does not trip, the exposed wiring is not ground fault protected.

Basically what I’m getting at is the GFCI outlet protects between the outlet and the EVSE, while the EVSE’s CCID function protects between the EVSE and the Prime. My understanding is based on these two pages from the manual.