Issues charging at home on 240v with the Portable charger

[Explorer83]

TLDR:
I just had a 240 V installation with 50 amp service installed by professional electrician to charge at home using the portable Rivian charger. Just about every time I charge the GFI circuit breaker trips after about an hour.
could this be a problem with the truck and or charger? G2 R1 T dual large.


I’ve had the electrician come out and replace the circuit breaker now and the NEMA outlet, they say there is nothing else they can do.

I will be testing it again on Saturday when I get home from my trip and if it pops again, my next target is going to have to be Rivian. I live in Florida, the truck parks outside and as always, it’s hot as hell, one thing I have not yet looked into is the battery temperature while charging.

I would really like to get this resolved without having to go to the hardwired charger, and I’m not altogether sure that that would solve the problem if it is a charging or truck issue.

Sponsored

 

[Polar]

Hardwire will not require a GFI, unless your local code requires it for some reason.

 

[Explorer83]

Sorry, I just realize this would’ve been better for the technical issues forum, but I don’t see a way to move or delete it. Mods feel free to delete or move as necessary thanks.

 

[Explorer83]

Hardwire will not require a GFI, unless your local code requires it for some reason.

Its possible that the GFI is causing the issue to be sure, but as is, the electrical code requires it, if a HW install avoids that could be worth looking into. Thanks.

 

[Dark-Fx]

My money is on two bad GFCIs, if it's not a bad connection somewhere.

 

[mudito]

My money is on two bad GFCIs, if it's not a bad connection somewhere.

I agree with this. No need of a GFCI for this application and some of those tend to fail when exposed to continuos loads.

Assuming the wire gauge is the appropriate, you should have no issues

 

[thrill]

The code-mandated GFCI outlets for EV charging is an overreach, as any decent quality EV charging unit does circuit testing itself, and will often trip the GFCI system. GFCIs certainly come in a variety of quality levels themselves, and what may work for many applications may well not work well for EVs, especially in a hot and humid environment such as Florida where heat dissipation is already more challenging.

 

[Dark-Fx]

The code-mandated GFCI outlets for EV charging is an overreach, as any decent quality EV charging unit does circuit testing itself, and will often trip the GFCI system. GFCIs certainly come in a variety of quality levels themselves, and what may work for many applications may well not work well for EVs, especially in a hot and humid environment such as Florida where heat dissipation is already more challenging.

The test is supposed to happen before the connection is initiated. If it's tripping after an hour, there is something else going on.

 

[KBabione]

Have you tried dropping the amperage pulled from 32 to 24 in the truck and seeing if the GFCI still trips? Might be worth a shot to help you narrow down the issue.

 

[Mathme]

Couple of thoughts here:
As @KBabione said, try reducing the amps to 24.

On a 50amp circuit, you should be able to pull 40 continuously...more than the portable charger can put out.

I'd see if a friend has an outlet you can borrow and try plugging your truck/portable charger in there. If the behavior is the same, then it's a truck/charger issue.

Likewise, if there's another Rivian user or a friend with a portable EV charger you could plug into your outlet and try. If the truck charges longer than an hour in this situation, then it's likely the portable charger.

I'd also think about a different solution long term over using your portable charger. Those heavier-duty plugs aren't really designed to be plugged/unplugged like a standard household outlet. They will loosen up over time and that'll create heat and cause issues. As an alternative, you could buy a 50amp household charger with the 14-50 plug and install it yourself. I have a Wallbox unit that's been used to charge 2 EVs for the past three years with no issues.

Try having a breaker installed without a GFCI and see if that works.

 

[jrmbadger]

I agree with Dark-FX - it's not likekly a GFCI issue and something is probably overheating. In addition to the good troubleshooting steps and considerations that Mathme recommended, consider the following:

What wire gauge did the electrician use? For a NEMA 14-50 outlet with a 50 amp circuit, you will need to use either 4 gauge romex or 6 gauge THNN in conduit. You'd be surprised how many licensed electricians try and cheap out and use 6 gauge romex. If you have a particularly long run from the box, you may need to size up the wire even more.

What outlet type? for EV charging you need an industrial grade outlet like a Bryant or Hubble. For example, this one is highly recommended: Bryant NEMA 14-50. The cheap ones from Home Depot do not have enough contact area in the plug area and so they heat up and will eventually burn up. They are not made for continuous use.

Ask your electrician what they used. If everything else checks out, it could just be a bad mobile charger.

 

[Explorer83]

Have you tried dropping the amperage pulled from 32 to 24 in the truck and seeing if the GFCI still trips? Might be worth a shot to help you narrow down the issue.

Yes, originally started at standard 44 amps, turned it down to 30 amps still tripped in an hour

 

[Explorer83]

Couple of thoughts here:
As @KBabione said, try reducing the amps to 24.

On a 50amp circuit, you should be able to pull 40 continuously...more than the portable charger can put out.

I'd see if a friend has an outlet you can borrow and try plugging your truck/portable charger in there. If the behavior is the same, then it's a truck/charger issue.

Likewise, if there's another Rivian user or a friend with a portable EV charger you could plug into your outlet and try. If the truck charges longer than an hour in this situation, then it's likely the portable charger.

I'd also think about a different solution long term over using your portable charger. Those heavier-duty plugs aren't really designed to be plugged/unplugged like a standard household outlet. They will loosen up over time and that'll create heat and cause issues. As an alternative, you could buy a 50amp household charger with the 14-50 plug and install it yourself. I have a Wallbox unit that's been used to charge 2 EVs for the past three years with no issues.

Try having a breaker installed without a GFCI and see if that works.

The problem is the GFI is required by the US electrical code, according to the electrician who did the work, and they will not install without one. So my only option would be finding somebody who does it without a license or trying to do it myself neither of which I’m comfortable with doing.

I have a Leyman’s understanding about heat in electrical circuits, and my initial instinct was that a bad GFI is tripping at a heat range that it should not be. However the hottest temperature I saw on the face of my GFI prior to it tripping was only 110°F and unless the GFI is truly faulty, I cannot see that temperature causing a trip.

I do know that the electrician used six gauge wire for the install, but I do not know the type that was used. The length of the run from my circuit breaker to outlet is approximately 10 to 12 feet. I do have the correct EV specific Nema outlet, although the electrician had to install that on his second visit.

When I get back home on Saturday, I will try charging again at 30 A and see what the result is with the new circuit breaker.

 

[jrmbadger]

The problem is the GFI is required by the US electrical code, according to the electrician who did the work, and they will not install without one. So my only option would be finding somebody who does it without a license or trying to do it myself neither of which I’m comfortable with doing.

Before I switched to the Tesla Wall Connector, I used a NEMA 14-50 outlet exclusively with my Tesla mobile charger on a GFCI breaker and had exactly ZERO nuisance trips. NONE. There are many many many more of us who have successfully used a GFCI breaker with mobile chargers for years and had no issues.

GFCI works by measuring current on the hot leg and comparing it to the current on the neutral leg. If they are equal, that means that there is no ground short. If they are not equal, there is no short. The only issue with an EV charger is that sometimes you may get a trip when starting a charge, as the charger leaks a small amount of current to ground to make sure the outlet is grounded. This may trip a sensitive GFCI breaker, but would not do so during the middle of a charging session as you have indicated.

Removing the GFCI is unsafe and I would not recommend it. Consider the situation when someone is unplugging your EV charger. If you don't shut off power at the breaker there is a risk of electrical shock. Those metal prongs on the plug are fairly long and it takes a bit of force to remove them. Let's say you accidentally make contact with those prongs as you are removing them. Now you have 120v or 240v (depending if you make contact with just one hot leg or both) @ 50AMPS of current running through you. Not something you wanna experience. On the other hand, if you have a GFCI, most likely the breaker will trip to protect you and keep you alive.

If the breaker is tripping there is likely a problem in the circuit, wiring, or mobile charger. Breakers tripping in the middle of a charge cycle do so because they are too hot. That's how breakers work - they get hot and trip (most breakers). Inside a typical breaker, there is a bimetallic strip that acts as a heat sensor. When excess current flows through the breaker, the wire and the bimetallic strip heat up. Due to thermal expansion, the two metals in the strip expand differently, causing the strip to bend. This bending action trips the breaker and stops the electrical flow to prevent overheating and potential fires.

Excess current flowing through the wires can be caused by resistance downstream. This resistance can be caused by insufficient wire size, loose connections, poor connections between the outlet and the plug, and poor connections between the plug tail (the NEMA 14-50 tail that came with the mobile charger) and the mobile charger itself (- its pretty stiff and you have to push really hard to get it to properly seat). Over time, these problems can cause the circuit to heat up. As the circuit heats up, the resistance goes up further (heat increases resistance). This causes a positive feedback cycle that eventually trips your circuit. This can also happen over time due to expansion and contraction of the metal wires and contacts due to heating the wires which may loosen the wires.

If I were in your shoes, I'd rule out the Rivian charger first, then I'd ask some serious questions from my electrician about the supplies used (wire sizes - see my earlier post - and outlet choice).

I'm not an electrician, but I installed my own NEMA 14-50 outlet and then later converted that to a Tesla Wall Connector on a 60 amp circuit and then added a second Wall connector to charge my rivian. I extensively researched the electrical code and how to do it safely prior. I have never had an issue with nuisance tripping. When I got my NEMA 14-50 inspected, the main issue the inspector wanted to verify is that I used a GFCI breaker.

On the other hand, there are tons of stories in the forums of licensed electricians installing wire that is too thin to handle the continuous loads of an EV charger or cheaping out on non-commercial grade outlets.

Take a look at this video from Tom Moloughney of State of Charge - he knows what he's talking about. State of Charge

 

[jrmbadger]

However the hottest temperature I saw on the face of my GFI prior to it tripping was only 110°F and unless the GFI is truly faulty,

Just re-read your reply and saw the above.

The face of the breaker doesn't necessarily mean the rest of it (the actual electric part) isn't heating up. I would verify that the rest of the circuit is to code as stated above. Make sure they used 6 gauge THNN wires rather than Romex (NM).

Also, it could certainly be a bad GFCI breaker. Depends on the brand. Some are more prone to defects than others. Could also be a bad batch. My father in law has AFCI breakers that go bad every 6 or so months to a year.

Also could be a bad mobile charger. See if you can charge at a friend's house or at the service center, or if you can borrow someone else's mobile charger.

Sponsored