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I am quite unfamiliar with wiring in residential houses so bear with me. I have an electric car that I can charge with 32A EVSE. My main house fuse is 32A. I am curious if there is a device that can dynamically disconnect power for one specific socket if it detects that power draw if it approaches the 32A limit? I could probably get a bigger fuse, but it would be very expensive because I would have to pay a monthly premium in my electricity bill.

My reasoning would be that this would disconnect the car from charging, but not turn off the main house fuse with all the other appliances?

I have attached a crude drawing of what this device would look like. It would have a power meter on the main input of the house, and would measure the total current that the house draws. If it approaches the limit of the house fuse, a relay would disconnect a sub-circuit (the garage for example). enter image description here

Is this something that exists? This would seem very handy to have, even if you have to redo some wiring.

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  • \$\begingroup\$ Look for something like a Samhwa EOCR module. \$\endgroup\$
    – Kartman
    Nov 9, 2021 at 10:30
  • \$\begingroup\$ Woudn't it be better to measure current and tell the car to charge at a lower current? \$\endgroup\$
    – Justme
    Nov 9, 2021 at 10:48
  • \$\begingroup\$ @Justme that would be better, however considering that the current consumption changes dynamicly (washing machines, ovens,....) and that you have to change the max current on the car every time, its not very practical. So i was looking for a way to automate this process \$\endgroup\$ Nov 9, 2021 at 12:41
  • \$\begingroup\$ I'm pretty sure EV charging stations aren't allowed to share a circuit with anything else. \$\endgroup\$
    – Hearth
    Nov 9, 2021 at 14:18

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The charger must be connected to a suitable rated breaker not shared with electric heater or motor outlets. Ceiling LED lighting would be OK to share.

You ought to learn more about residential power basics and correct the problem with an electrician. (Use google image search to learn)

p.s. @Kartman if he can afford a Samwha EOCR he can afford an electrician. We can't possibly understand his regional unstable grid issues that can trip breakers from voltage swings NOR appreciate his undefined other residential power distribution issues.

A proper solution is to use the suitable cable to a dedicated suitable breaker, and not one shared, say by an oven/stove.

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  • \$\begingroup\$ Tony, agreed. Definitely the case of doing a ‘work around’ where the solution is guaranteed to be substandard vs just doing properly the first time. ‘Hwa’ vs ‘wha’ - I’ll send Mr Kim my apologies. \$\endgroup\$
    – Kartman
    Nov 9, 2021 at 20:51

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