Redoing, the Engineer’s mood

I’m redoing my home charging installation. After the successful three phase 3×20 A installation done elsewhere for 66 km/h charge (I wish it was mine!), I started to think “Why can’t I be able to use my full/all Amps contract?”

I have a 30 A contract. Until now I was able to squeeze up to 20 A max. If I changed the wires to the garage I would be able to get the 30 A. But that’s a risky business, to take away the old wires and insert new ones for the 30 A rate. I know how to do it. I know it can go smoothly, and it can go pretty bad. And when it comes to Murphy’s law, I tend to bet on the success of the bad result WHEN the risk involved is too much. So, changing the wires is not an option, at least for now.

After some considerations and analysis, a different solution was found: I have another circuit going along the garage circuit, the washing machine circuit. It’s the same as the garage circuit, and the same length. First tests were OK. Then I presented the solution to my colleague PSantana: the thinking aloud method works 🙂 it’s not only to be taught, it really pays of when you do it yourself 🙂  It turns out a permanent parallel connection of the two circuits might not be a bad idea INSTEAD of changing the wires.

After some backtrack thinking I remember the first time I heard about this parallel business! Nuno showed me a portable circuit he did for parallel wiring!

Screenshot_20160724-095234
Test with 29 A charging for half an hour: working flawlessly, using a parallel installation of two 16 A circuits; the 32 A shown is not active, it’s the charger’s upper limit

Alexmol suggested a 40 A 30 mA differential breaker, just in case. What I did not tell him: during the test, that breaker, if already installed, would have saved me a short yet close encounter of the third kind  🙂

For years and years I’ve worked with 230 V and always avoided a short thru me 🙂 During the test phase I was so involved with the proper connections that I forgot that one of the wires was live! Not a big deal: a small reminder that it pays to be cautious and attentive 🙂

So, now, the final installation commences. Wish me luck!

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