EV Chargepoint - Wiring Options

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No, external chargers have had that problem.
If I understand what is being said correctly, there seems to be a bit of a difference of opinion here (regardless of whether the charger is internal or external to the car) - you are describing 'a problem', but ChewChew seems to be calling it a 'safety feature'.

Kind Regards, John
 
Please note some others' unhelpful posts above have been removed.
I suspect ChewChew believes what the adverts tell him.
 
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I'd still go with a dedicated radial for the charger otherwise you will end up with some fat cables accounting for the load of lights, sockets and charger.
 
I suspect ChewChew believes what the adverts tell him.

Not sure if it was intentional, but this does highlight a good point - don't accept everything on face value you see/hear/read including on fora such as this.

No matter how well intended sometimes we do post stuff in such a way it comes across as fact where it may be opinion. I'm guilty of this ref my charger comment, which I'll put right in a later post. And there are always those who want to tease, mislead and at worse troll whatever their motives may be.

caveat lector
 
That is true.

There is also the case where someone truly believes what they are saying when in actual fact it is not correct.
 
I've got a pod point 7kw charger for my Nissan LEAF. I had it fitted as part of the whole 'buying the car' thing.
What I'm saying is that it was a professional install. I'd normally do electrical work myself, but on this occasion it didn't make sense to.

They used 6mm t&e to connect mine, which I would've probably used myself.
However, whilst it's fine, the LEAF draws 6.6Kw for about 4-5 hours, and after this time, the cable (clipped direct to the blockwork) inside my garage is really quite warm.... It's ok, and I appreciate that cables can warm up in use, but if I ever fit one in the future, I'd use 10mm cable.

Dan
 
about 8-10metres I suppose... But that's what I'm saying, 6mm is fine with regard to volt drop calcs and current carrying capability, but it's not often in a domestic setting that you see such a big load carried for so long... Induction hob, electric showers etc.. are far more short bursts of power, so you don't see the heating effect. The cable probably gets to maybe 40-45C max, but as I said, if I was to fit one again, and if I was using T&E, then I'd use 10mm to reduce the heating effect.
 
.... it's not often in a domestic setting that you see such a big load carried for so long... Induction hob, electric showers etc.. are far more short bursts of power, so you don't see the heating effect. The cable probably gets to maybe 40-45C max, but as I said, if I was to fit one again, and if I was using T&E, then I'd use 10mm to reduce the heating effect.
As flameport has said 6mm² T&E is 'rated' at 70°C. I've never been certain, but I presume the implication is that the tabulated CCCs we use indicate (undoubtedly with some 'safety margin') the current which, with the installation method in question, "will" raise the conductor temp from 30°C to 70°C. On that basis 6mm² 'clipped direct' should get to something approaching 70°C (a 40°C rise from the assumed ambient of 30°C) at a current of 47A. That being the case, your 40-45°C (a temp rise of 10-15°C from that assumed ambient) doesn't sound far off what I would expect.

Indeed, if one assumes a square law relationship between current and heat production, hence temp rise, one would expect the temp rise with 27.5A flowing continuously to be about 2.9 times less than with 47A. A 40°C rise (with 47A) divided by 2.9 would therefore equate to a roughly 14°C rise with 27.5A flowing - which is within the 10-15°C range. Admittedly, your ambient is presumably going to be far less than the assumed 30°C, but at least this gives one an idea!

Kind Regards, John
 
Admittedly, your ambient is presumably going to be far less than the assumed 30°C
Not always.

Your ambient has been over that for periods of several hours this week, and EV charging can be, I expect, a sustained load for several hours.

I hadn't thought about this before, but given the nature of the load and the possibility of rising temperatures, I would consider it prudent to assume a 40°C ambient when doing cable sizing calculations for EV charging.
 

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