10mm joined to 6mm for exterior charger

[David Rann]

I have a job where the client wants a 7kw car charger 50 meters away from his house. The problem is there is a 6mm that's been pre wired 10 meters through his house from the main consumer unit to an exterior wall and sealed up. So I would have to use that and join onto the 10mm exterior and put on a 32amp MCB. Can see any issues doing this?

 

[buzzlightyear]

So what do your calculations say.
For V/D on the new circuit .

 

[Gavin John Hyde]

Why 10mm ? Depends on cable run and voltage drop.
Assuming the 6mm is TandE then barring anything too exotic you will be good for a 32/40 amp mcb.
I had a few instances of a ev charger tripping a 32 amp mcb and some manufacturers recommend a 40 amp.
Might be worth checking?
You could look at taking 2 core swa from the existing cable in suitable outdoor box. Keeps costs down, Using armour as cpc in cable run. Dont terminate the armour as the earth at charger as you will use a rod.
It is late and without doing the calculations on voltage drop you might manage to use 4mm 2 core swa depending on install method but 6mm 2 core swa will almost certainly be adequate . Saves using 10mm.

 

[buzzlightyear]

10 mm would be used 50mtr for that install .32 amp mcb. calcalated.

 

[Gavin John Hyde]

10 mm would be used 50mtr for that install .32 amp mcb. calcalated.

I havent done the calcs myself

 

[David Rann]

I've done the calculations and it comes out at 10mm but what Im saying would the first 10 meters be okay in 6mm. The first 10 meters works out less than a half a volt volt drop

 

[Wilko]

Hi - can I ask what is it you are concerned about? Is it the voltage drop, the ccc change, the cpc size and the earthing system of the installation, the cable installation method and jointing, or ...

 

[David Rann]

Hi - can I ask what is it you are concerned about? Is it the voltage drop, the ccc change, the cpc size and the earthing system of the installation, the cable installation method and jointing, or ...

Voltage drop mate. Just seems illogical way round. I'm running 2 core 10mm to charger exterior and making a tt island at source.

 

[Wilko]

All good then .

 

[David Rann]

All good then .

Okay thanks I thought it was but it's always good to have confirmed. Have a good day

Cheers

 

[Andy78]

Calculate the run as it is, with the portion of 6mm and portion of 10mm for peace of mind with the vd values.

 

[David Rann]

Calculate the run as it is, with the portion of 6mm and portion of 10mm for peace of mind with the vd values.

Hi Andy

I've donw that and its well within its parameters at both points.


Cheers