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is the lead definitely all the way in at the wall box? Try pushing it in a bit futher.
I had something similar with my first charge, turned out the lead has a snugger fit than I was used to with my old leaf.
 

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Discussion Starter · #22 ·
Yes I can tweak it to say 28A easily, but I don't see the point. This thing's clearly getting hot; I've now had 4 or 5 repeatable trips, all of these are somewhere around 10-20 minutes into a charge session, so I really don't think it's any high frequency glitching. Deffo got to be a thermal issue. If the temp on outside of casing's 43, what's the hottest it's getting inside? And is that heat going to degrade it further, even if I reduce to say 28A? Got to be a new MCB. No question. And then I can pull the old one apart & peek inside ! :) :) :)
 

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Discussion Starter · #23 ·
is the lead definitely all the way in at the wall box? Try pushing it in a bit futher.
I had something similar with my first charge, turned out the lead has a snugger fit than I was used to with my old leaf.
This problem's not at the wall box EVSE itself. It's inside the mini Consumer-Unit that's wired off the Grid-meter, on the other side of the gge. EVSE & Car stuff is fine thx.
 

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My consumer unit also kept tripping after 15-20ish minutes, in exasperation ready to give in and try a public charger, I noticed I could give it a bit more of a shove and never had the problem ever again.
 

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40kW Leaf Tekna & 22kW Zoë Q210 dynamique intens
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All things seem to point to old MCB that’s had a hard life charging an EV.

Cheap to swap and the best first place to start, I’d lay money on a new breaker fixing the problem.

Although they are supposed to be able to be loaded slightly above the face rating in my experience if you load a breaker to near its limit regularly and for a prolonged period of time sooner or later it plays up.

I used to install and maintain theatre lighting that had 2400w mercury discharge lamps in it I’ve seen circuits loaded heavily do this we used to have the breakers replaced as preventative maintenance (it’s embarrassing when the whole stage goes dark during a live performance)
 

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"Application exampleThree MCBs are to be installed side by side inside an enclosure. The ambient temperature inside the enclosure is at 40°C. The required maximum load current drawn per MCB = 29A.Determine whether 32A MCB would provide suitable solution.• From the Temperature Derating table, The nominal trip current (In) of 32A MCB operatingat 40°C is derated to 30.4A• From the Grouping Factor table, Three MCBs installed side by side have a groupingfactor K(g) = 0.95• Combined effect of temperature derating & grouping factor, 30.4 x 0.95 = 28.88AIn this application the 32A MCB would trip at 28.88A and therefore be unsuitable to supplythe max 32A load that is required. In this case a 40A or higher MCB should be selected instead."
My Rolec EVSE installed in late 2017 has a C40 RCBO fitted from new:

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Inside the house is a Mini-CU just for the car that goes to the meter tails:

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No false trips charging my Leaf at 6.6kW.
 

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From memory a B type MCB will hold 32A forever. As others have said, it‘s the RCD, not the overcurrent device that’s tripping. RCDs work by measuring the current flowing in to the circuit (along the live leg) and the current flowing out of the circuit (along the neutral leg). It should be the same (residual current = 0). If there is a leakage path to earth, some of the return current will flow through that back to either the PME connection at your meter or direct to the substation, bypassing the RCD and leading to a measurable residual current.

If the difference between the current out and current back exceeds 30mA (the 0,03A marking in the picture) then the unit will trip.

Not immediately obvious to me why it trips after so long or only at higher current.
The OP has stated that it is the LH MCB tripping!
Why are people here claiming the RCD has tripped?
It's probably a faulty MCB, change it and repeat the experiment...
 

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No false trips charging my Leaf at 6.6kW.
The leaf only draws 27.5A max while charging that breaker is only loaded to to around 85% of its rating.

I expect my RCBO to last a long time.

My charging circuit has a 32A breaker on it, if I change up from the leaf to a car that had a bigger charger on board I would fit a 40 breaker and make sure it was on a 10mm cable to the charge point.
 

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The leaf only draws 27.5A max while charging that breaker is only loaded to to around 85% of its rating.

I expect my RCBO to last a long time.

My charging circuit has a 32A breaker on it, if I change up from the leaf to a car that had a bigger charger on board I would fit a 40 breaker and make sure it was on a 10mm cable to the charge point.
I think you missed the entire point of my post - which is that the RCBO in my Rolec is 40 amp not 32...obviously done for a reason.

BTW according to my Loop monitor the Leaf actually draws 6900 watts - at 230v that's 30 amps not 27.5A. Not sure how accurate the loop is though.
 

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if I change up from the leaf to a car that had a bigger charger on board I would fit a 40 breaker and make sure it was on a 10mm cable to the charge point.
You shouldn’t need to. B curve shows disconnection time at 40A is 1,000 seconds (ie 16 minutes) Curve doesn’t even show a time for 31A.

My first charger (PodPoint) recommended a 40A breaker but the car can overcurrent for a while before the breaker is specified to trip. Overrating circuits just lengthens the fault clearance time.
 

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Charging at 31.5A, it's getting up to 43C about half-way up, so looks like internal heating somewhere in the middle.
That's normal. The bimetal bit is in there being slow-cooked, as it should be running near max current.
The upper terminal/cable being warmer is also expected, because (drum roll) heat rises (ta-dah).
 

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I do wonder if there needs to be some sort of regular inspection required for these EV setups
Domestic installations are recommended to be checked every 10 years, but of course people don't bother even if they actually think about it.
I think insurance companies could get involved by making regular inspections of electric, gas and water systems a condition of cover, much like with cars.
 

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BTW according to my Loop monitor the Leaf actually draws 6900 watts - at 230v that's 30 amps not 27.5A. Not sure how accurate the loop is though.
Probably more accurate than the assumption that the supply is 230v, although if the monitor is measuring current and assuming the line voltage then your calculation back to current is correct.

DNOs didn’t generally reduce the voltage when the nominal value was harmonised so it’s probably closer to the original 240 nominal.
 

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Probably more accurate than the assumption that the supply is 230v, although if the monitor is measuring current and assuming the line voltage then your calculation back to current is correct.

DNOs didn’t generally reduce the voltage when the nominal value was harmonised so it’s probably closer to the original 240 nominal.
The mains voltage at the house varies from 230v to 235v. I've only seen it get to or go over 240v once during the beast from the east.

I've compared a difference reading on the Loop with a 3 pin kWh meter running a high wattage appliance and while I don't recall the exact figures it was actually surprisingly accurate, although as you say as it's only a current clamp the voltage is assumed.
 

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BTW according to my Loop monitor the Leaf actually draws 6900 watts - at 230v that's 30 amps not 27.5A. Not sure how accurate the loop is though.

My charger has a readout on it, my 40 Leaf has never drawn more than 27.5A

In theory 6.6kW (6600 / 230 = 28.695A)
so theoretically it could draw just over 28.5A.

Even when I plug in my leaf at low SOC it just doesn’t draw that much.

Maybe my charge point is not accurate all I can go on is the figures I have seen reported from my charger they seem to correlate to the voltage available / amps drawn that it is pulling just under 6.6kW though when observed over a few different mains voltages the maths all seem watertight, you tell me?
136470
 

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Overrating circuits just lengthens the fault clearance time.
This is true, but provides greater headroom on the trip so as it gets old your much less likely to wake up in the morning and realise you’re car didn’t charge last night due to an old breaker, so you have a 20min detour to the local rapid on your way to work this morning! 😂

In my experience if you develop a fault on something like a 32a car charger circuit that warrants a 40a MCB to trip out that’s more of a magic blue smoke, charger goes bang situation than a slow burner so in a real world situation it’s likely to disconnect pretty quickly.

I learned the hard way when a large refrigeration unit tripped out on an RCBO and ruined £5k worth of my food stock that some circuits you don’t want to switch off unless it’s to prevent something catching fire! 🤣

I switched all my chillers / freezers to slightly overrated MCB’s and I’ve never had a problem since.

I always like to add a large dose of reality to the “on paper theory” whenever possible.
 

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The mains voltage at the house varies from 230v to 235v. I've only seen it get to or go over 240v once during the beast from the east.
Mine is regularly 245v. I only live a couple of hundred yards from the substation but that still looks like 240 nominal.

Spec is 230 +/-10% so anything from 207 to 253 is acceptable. I don’t believe the DNOs went round tapping transformers down when the value was harmonised because they were still in spec.
 

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That’s a smart looking charger. What is it?
It’s a portable 32A commando charger from EV one stop.

I’ve never had a fixed charge point as it was cheaper and easier for me to fit a 32A outlet as I charge at 3 locations so portable was better for me.

As far as I can tell it’s readout is pretty accurate.
 
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