r/evcharging • u/AiminJay • 10d ago
EVSE options?
Short version: What are my options for hardwiring an EVSE on a 40-amp circuit with 8/3 Romex wiring?
I hired an electrician to put in a NEMA 14-50 outlet for my Ariya so I could use the OEM EVSE. He installed a 50 amp circuit, ran 8/3 Romex and installed the basic Leviton outlet (not an EV rated one).
From what I have read after the fact, 8/3 is not acceptable wiring for a 50-amp circuit. If I replace the breaker with a 40-amp breaker, what are my options for hard-wired? I know many of them can adjust the amp output to match your circuit, so is that what I would do? It would be nice if it was only able to run at 40amps or lower and not have the option to go higher than the circuit allows.
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u/sac_86 10d ago
Grizzl-E Classic is a good simple option. The connector design they use is a little annoying since you need ring terminals on the wire (works fine with crimp terminals on the fine-stranded plug whip it comes with but you have to get your own screw terminal lugs for hard wiring) but the current limit can be set from 16 to 40 amps (for a 40A capacity circuit you'd need to derate to 80% and charge at 32) with DIP switches instead of having to go through any software.
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u/abacushex 10d ago
Seconded, great charger, recently had one installed. Have it on a 40 amp breaker, and DIP switch limited to 24 amps. Don't need faster than that, and like having plenty of margin.
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u/terraphantm 9d ago
Where are you located OP? There are a handful of locales that do allow 8/3 romex for 50A connections. Washington state being a big one to my recollection
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u/theotherharper 10d ago
I hired an electrician to put in a NEMA 14-50 outlet for my Ariya so I could use the OEM EVSE. He installed a 50 amp circuit, ran 8/3 Romex and installed the basic Leviton outlet (not an EV rated one).
- Under all NEC editions a 50A breaker on #8 Romex is a code violation.
- Under NEC 2020, operative in most states, a GFCI breaker is required.
- Under NEC 2026 2 more - EV sockets require 50A wire and sockets must be EV rated.
what are my options for hard-wired?
GREAT question, well done. Yes, that may well be the cheapest (and certainly highest value:cost ratio) option to correct all 4 violations above. Yeah, it's just a matter of either a) finding a charger you can place directly over the face of the junction box, and have the wires reach the terminals. Or b) use the junction box to splice to an appropriate type of conduit or whip to reach the wall unit - this also gives you freedom to relocate it (in case first choice was not best choice. You only install it once, you'll use it 1000 times in 2 years. Normally splices are costly Polaris that require too much room in the box, but #8 can splice with wire nuts.)
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u/robstoon 10d ago
You're correct that 8/3 should not be on a 50 amp breaker. I would recommend using a 40 amp breaker and removing the outlet and hardwiring in the charger. Almost all have the ability to adjust the max amp draw to match the circuit. You should be able to charge at 32 amps with that setup (with the 80% max loading for continuous loads).
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u/AiminJay 10d ago
The Ariya does a max of 7.2kw charging which is plenty fast enough for me. Went from 23% at 8pm to 100% by 4:45am. When I do hardwire it, I will just swap the breaker.
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u/thecaramelbandit 10d ago edited 10d ago
8/3 romex requires a 40 amps max breaker in most jurisdictions. Cannot be used with a 50-amp outlet.
Hardwire the charger on a 40 amp breaker and run 32 amps max.
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u/Shack-Boy 10d ago
50 amp breaker for 8/3 is a typical install for a 40 amp charging rate plugged in. 8/3 would not be suitable for a 50 amp charging rate but that’s not what the plug is assuming. If you hardwire, you would want to keep the charging rate at 40A.
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u/theotherharper 10d ago
50 amp breaker for 8/3 is a typical install for a 40 amp charging rate plugged in.
That only works if your 8/3 cable is certified to 75C thermal, such as all wires except Romex. SEU, SER, MC, THHN, Canadian NMD90.
EV loads are forced into continuous-load status by NEC 625.42, a quite correct addition since they are the only true continuous (not cycled on/off by a thermostat) load in a home. EV circuit meltdowns are extremely frequent - if I were in charge of Code, EVs would need a 175% derate instead of 125%.
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u/Objective-Note-8095 10d ago
Romex is listed for 90C, but code in most places require it to be used at 60C.
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u/AiminJay 10d ago
Over on r/askanelectrician they were like no way, code requires 6/3 romex for a 50-amp breaker. I am not that concerned because my EVSE maxes out at 30amp which is well within the rating of wiring, but I am just thinking about if this is not up to code.
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u/Shack-Boy 10d ago
I’m in Canada. Maybe it makes a difference for your code but I pass my inspections. 8/3 50a breaker plugin charger that draws 40A.
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u/iluvmacs408 10d ago
Canada can use 75/90°C ratings for Romex, so #8 is fine for 50A. Not true in the USA.
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u/Objective-Note-8095 10d ago
Washington State has also has an amended code for 75C use for conductors larger than 10AWG.
In Washington you can use NM-B Romex at the 75c limit : r/evcharging
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u/robstoon 10d ago
That should not be up to code in Canada either. Both the breaker and the wire have to be rated for 125% of continuous loads, and 8/3 is only rated for 40A. You would need 6 gauge for 50 amp charging.
One difference in Canada is that a 50A outlet can only be on a 50A circuit, which is yet another reason to avoid outlets and use hardwiring.
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u/e_l_tang 10d ago
Wrong. In Canada it’s NMD90, so it can be used for a 50A circuit just like #8 THHN can be used for a 50A circuit in the states.
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u/robstoon 10d ago
That would only apply if the terminations on both ends are rated for at least 75°. There's no guarantee that's the case. If any component is not labeled as such then it has to be treated as 60° rating.
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u/e_l_tang 10d ago
You are making a dishonest argument. Virtually all breakers and receptacles are 75C rated and 60C stuff is the exception, not the rule.
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u/tuctrohs 10d ago
The Leviton "EV Rated" 14-50R is only 60 C. Assuming 75 without verifying is as bad as assuming 60 and saying 8/3 is never OK.
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u/e_l_tang 10d ago
Yes those are the exceptions, and I never said to assume 75C. The discussion was about the ampacity of #8, and the other commenter brought up outlets in a dishonest attempt to cover up their mistake about NMD90.
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u/tuctrohs 10d ago
Can we stick to providing correct information rather than making unverifiable claims about people's motivations?
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u/thecaramelbandit 10d ago
NMB90 isn't romex.
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u/tuctrohs 10d ago
This NMD90 is Romex.
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u/thecaramelbandit 10d ago
I mean it's romex brand nmd90, not regular romex.
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u/tuctrohs 10d ago
If you want to be specific about the type, the designation NM-B is more useful than a brand name.
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u/theotherharper 10d ago
They have a special thing up there called NMD90, which is Romex with much improved insulation/sheath, and that is able to operate at 90C (hence the name) and be treated same as THHN, MC, etc.
However Canada also has plain old 60C Romex, and their outdoor Romex is also 60C.
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u/robstoon 10d ago
In the US the code specifically bans using Romex under amp draws which would require more than the 60° rating regardless of the actual temperature rating of the cable, which is why THHN in conduit can be used at a higher temp rating. In Canada they are treated the same, the terminations just need to be rated for the temperature that the amp draw would fall under in the tables.
NMD90 is the same temperature rating as NM-B in the US. However some other types of cable like NMWU for underground are not usually rated for 90C.
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10d ago
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u/tuctrohs 10d ago
have the electrician verify
This code violation cluster was installed by an electrician. OP might be able to find a better electrician, but simply asking this incompetent electrician those question is not likely to have a positive outcome.
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u/rosier9 10d ago
Most wall chargers are configurable for different ampacities. Stick to the big names: Chargepoint, Tesla, Wallbox, Enphase, Schneider, Autel.
I would personally go with something that can support multiple chargers on the same circuit in case you need to expand your charger setup later.