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Run a 30A rated L2 charger on a 30A circuit?
http://www.myvwegolf.com/forum/viewtopic.php?f=11&t=1718
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Author:  NoSmoke [ Sun Feb 10, 2019 8:41 pm ]
Post subject:  Run a 30A rated L2 charger on a 30A circuit?

Was wondering if breaker trip problems might occur? Can chargers be adjusted to deliver fewer than rated amps?

30A, 220V is what I already have run to a detached garage - would like to avoid upgrading if possible.

Thanks for any info....

Author:  f1geek [ Sun Feb 10, 2019 8:52 pm ]
Post subject:  Re: Run a 30A rated L2 charger on a 30A circuit?

Not a good idea to pull 30 amps on a 30 amp circuit. Trying to burn down the house? You probably should consult a licensed electrician. To my knowledge, you should not pull more than 80% of the circuit rating. If you only have a 30 amps circuit, don't pull more than 24 amps. If you can set the EVSE to 24 amps, that's what you should do. Otherwise, install an EVSE rated at 24 amps.

Author:  NoSmoke [ Sun Feb 10, 2019 10:55 pm ]
Post subject:  Re: Run a 30A rated L2 charger on a 30A circuit?

f1geek wrote:
Not a good idea to pull 30 amps on a 30 amp circuit. Trying to burn down the house? You probably should consult a licensed electrician. To my knowledge, you should not pull more than 80% of the circuit rating. If you only have a 30 amps circuit, don't pull more than 24 amps. If you can set the EVSE to 24 amps, that's what you should do. Otherwise, install an EVSE rated at 24 amps.


I doubt the house would burn down - more likely the breaker would trip, maybe after a delay. You may well be right in saying no more than 80% should be drawn (on a continuous basis I would suppose) so there is some allowance for start-up surge current (if that applies to these EVSE devices). I note that the advertised 30A units call for a 40A circuit.

Would still like to know however if the 30Aers can be adjusted lower (to maybe 24A as you suggest). In any case, looks like a 220V, 20A unit would be maybe 3 times faster than a L1(?).

Edit: Just noticed that 24A units are available so that looks like the way to go alright.

Author:  Spektre [ Mon Feb 11, 2019 8:42 am ]
Post subject:  Re: Run a 30A rated L2 charger on a 30A circuit?

NoSmoke wrote:
f1geek wrote:
Not a good idea to pull 30 amps on a 30 amp circuit. Trying to burn down the house? You probably should consult a licensed electrician. To my knowledge, you should not pull more than 80% of the circuit rating. If you only have a 30 amps circuit, don't pull more than 24 amps. If you can set the EVSE to 24 amps, that's what you should do. Otherwise, install an EVSE rated at 24 amps.


I doubt the house would burn down - more likely the breaker would trip, maybe after a delay. You may well be right in saying no more than 80% should be drawn (on a continuous basis I would suppose) so there is some allowance for start-up surge current (if that applies to these EVSE devices). I note that the advertised 30A units call for a 40A circuit.

Would still like to know however if the 30Aers can be adjusted lower (to maybe 24A as you suggest). In any case, looks like a 220V, 20A unit would be maybe 3 times faster than a L1(?).

Edit: Just noticed that 24A units are available so that looks like the way to go alright.


Check out openevse - I run my unit at 24A on a 30A circuit. It is adjustable and the kit is repairable/replaceable, in case anything should break - unlike most commercial units where if it stops working out of warranty you're pretty much buying a whole new one.

Been using it for years now, very happy.

Author:  RonDawg [ Mon Feb 11, 2019 9:23 am ]
Post subject:  Re: Run a 30A rated L2 charger on a 30A circuit?

NoSmoke wrote:
Would still like to know however if the 30Aers can be adjusted lower (to maybe 24A as you suggest).


Some can, some cannot. Ones that I know have such adjustments are the Siemens and the GE DuraStation. These have physical jumpers in the case so it can’t be accidentally reset to the higher amperage.

There are a few others (I believe OpenEVSE is one) that is set via software, but considering how programming can go wonky in any device, I would feel much more comfortable with the above hardware-based solution.

Author:  JoulesThief [ Mon Feb 11, 2019 11:03 am ]
Post subject:  Re: Run a 30A rated L2 charger on a 30A circuit?

The emotorwerks 40 amp unit I have is adjustable. You do have to pull the cover off, and go inside to turn it down. Then you have to verify the amount of current it flows, before you button it back up together.

I'd think it better to future proof your residence, run a dedicated 50 amp circuit breaker and EVSE line only, so that in the future, if your main panel can handle it, you can run a 40 amp EVSE unit on your 50 amp dedicated circuit. Circuits are rated max of 80% of breaker capacity.

Author:  NoSmoke [ Mon Feb 11, 2019 3:28 pm ]
Post subject:  Re: Run a 30A rated L2 charger on a 30A circuit?

Thank you folks - I think my questions have been answered.

All I have to do now is buy an EV. :)

Author:  johnnylingo [ Mon Feb 11, 2019 5:59 pm ]
Post subject:  Re: Run a 30A rated L2 charger on a 30A circuit?

Remember of course that the e-Golf, like most EVs, will let you set a max amps on the car itself. However, the downside of doing that you'll have to manually set it back to max current any time you visit a true 30a changer, say at a public L2 charging spot, and this may get annoying if you're charging away from home often.

Author:  NoSmoke [ Tue Feb 12, 2019 10:32 am ]
Post subject:  Re: Run a 30A rated L2 charger on a 30A circuit?

Also good to know - thanks!

Author:  NeilBlanchard [ Tue Feb 12, 2019 2:05 pm ]
Post subject:  Re: Run a 30A rated L2 charger on a 30A circuit?

I think a 30A (or 32A) unit needs to be on a 40A cable and breaker. We have our 40A (JuiceBox Pro 40) on a 50A circuit.

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