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Discussion Starter · #1 ·
Hi Folks
Have a query on the size of a home charging cable please

I currently have a tethered type 1 cable on a Rolec charger [on tethered picture is is shown as a 6mm cable]

I also have a type 2 cable in the car which we use for public charging stations [on mobile picture this is shown as a 2.5mm cable]
As the model 3 came with its own cable for public charging I was thinking to use my old type 2 cable to use at home....i.e cut the plug off one end, crimp the cable ends with bootlace ferrule crimps and connect them into the Rolec charger

Would this work as cables are showing as different sizes, would the 2.5mm cable be OK in the Rolec unit when the existing tethered cable is a 6mm...??

Any help appreciated

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Are you a qualified electrician?
 

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The simple answer is that no, you cannot just swap a 6mm² cable for a 2.5mm² cable like this, and also that there is more to it than just chopping off a connector and using the cable. Each end of a Type 2 to Type 2 cable has a resistor in the connector, connected between the PP pin and PE, the value of which tells the charge point at one end, and the charger in the car at the other end, what the cable current rating is. For a 6mm² cable this resistor will have a value of 220 ohms (at both ends), denoting that the cable is rated to carry up to 32 A, for a 2.5mm² cable these resistors will be 680 ohms, denoting that the cable can carry up to 20 A.

For a tethered charge point there is no resistor at the charge point end, so instead the charge point has to be configured internally to ensure that it never advertises a current (via the Control Pilot signal) that is greater than the fitted cable rating. A 2.5mm² cable cannot safely conduct 32 A, for example, in the case of the multicore flex used for charging cable it's only rated to carry 20 A.

You could remove the Type 1 connector from the 6mm² tethered cable and fit a 32 A Type 2 connector. Not hard to do, but does require access to a hydraulic crimping tool, and the means to verify that the connections have been correctly made. It's a bit fiddly to do, as there's not a lot of room available to get the jaws of the tool lined up properly, but also not hard if you're familiar with making crimped cable joints of this size. I find it's a lot easier to do with the hydraulic crimp tool held in a vice, saves having to try and grow a third arm and hand.
 

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To be fair, not all electricians will l understand how the IEC61851 protocol works, and why the value of the PP to PE resistor matters. Fitting a new connector to a charge cable isn't a difficult job, and it doesn't fall foul of any laws or regulations, either. Technically, it's little different to wiring a domestic plug, just on a bigger scale, with the need to use a pretty powerful crimp tool. There are obvious safety issues, but these can be addressed with a modicum of care and understanding as to how to do the job.
 

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Discussion Starter · #6 ·
Thanks all, will contact the guys that fitted the Rolec unit originally then and get them to change the cable to a type 2 cable
Ta for taking the time to reply
 

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TBH, changing the cable in the charge point really is an easy DIY job, much easier than changing the connector at the end of the cable. Several suppliers sell tethered cables ready made up, and if you can use a screwdriver and both understand safe isolation and have the means to check it, it's a very quick job (maybe 30 minutes maximum).

The process would be:
  • Isolated the supply to the charge point at the consumer unit or connection point.
  • Remove the front cover of the charge point and check that there is no power to the unit
  • Take a photo to verify the cable connections for reference later, specifically the L, N and PE, plus the CP, that connect to the charge cable (these are all screw terminals on your unit).
  • Disconnect the charge cable terminals, loosen the cable clamp and the cable gland that secures the cable, and carefully remove it
  • Fit the new cable in the gland, feed it through the cable clamp, and secure the wires in the terminals, making sure to torque them up well (between 2.5 N-m and 3 N-m for the three larger terminals, which is pretty damned tight).
  • Double check that all wires are in the correct terminals and are secure
  • Make sure the cable grip and cable gland are tight, and then dress the wires neatly inside the enclosure
  • Replace the cover and make sure it's secure
  • Turn the power back on and do a functional check to ensure the charge point works, checking that the RCBO in the unit trips when the test button is pressed.
 

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Discussion Starter · #8 ·
TBH, changing the cable in the charge point really is an easy DIY job, much easier than changing the connector at the end of the cable. Several suppliers sell tethered cables ready made up, and if you can use a screwdriver and both understand safe isolation and have the means to check it, it's a very quick job (maybe 30 minutes maximum).

The process would be:
  • Isolated the supply to the charge point at the consumer unit or connection point.
  • Remove the front cover of the charge point and check that there is no power to the unit
  • Take a photo to verify the cable connections for reference later, specifically the L, N and PE, plus the CP, that connect to the charge cable (these are all screw terminals on your unit).
  • Disconnect the charge cable terminals, loosen the cable clamp and the cable gland that secures the cable, and carefully remove it
  • Fit the new cable in the gland, feed it through the cable clamp, and secure the wires in the terminals, making sure to torque them up well (between 2.5 N-m and 3 N-m for the three larger terminals, which is pretty damned tight).
  • Double check that all wires are in the correct terminals and are secure
  • Make sure the cable grip and cable gland are tight, and then dress the wires neatly inside the enclosure
  • Replace the cover and make sure it's secure
  • Turn the power back on and do a functional check to ensure the charge point works, checking that the RCBO in the unit trips when the test button is pressed.
Thanks...that wouldn't be a problem to do...just trying to find the correct cable would be the issue I guess
Just couldn't understand why the tethered is 6mm and the one for public charging is only 2.5mm...but your first post explains why
 

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Thanks...that wouldn't be a problem to do...just trying to find the correct cable would be the issue I guess
Just couldn't understand why the tethered is 6mm and the one for public charging is only 2.5mm...but your first post explains why

There are several suppliers of made up tethered cables. I now only use these cables from EV Chargeking (no connection with them other than as a customer) because they use quite the best quality cable I've seen, and what's more the cable is made in the EU, to an assured standard (I've had my fingers burned with a crappy Chinese made cable): Unique Tesla charging cables - evChargeking

(ignore the way the link shows as Tesla, although they also do a very neat Tesla pigtail, with the button to open the charge port: Unique Tesla charging cables - evChargeking )

I have a spare, brand new, ~5m longTesla pigtail cable here if you want it. I bought it to fit to our second charge point when I owned a Model 3, but never got around to installing it and have since sold the Model 3.
 

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Discussion Starter · #10 ·
There are several suppliers of made up tethered cables. I now only use these cables from EV Chargeking (no connection with them other than as a customer) because they use quite the best quality cable I've seen, and what's more the cable is made in the EU, to an assured standard (I've had my fingers burned with a crappy Chinese made cable): Unique Tesla charging cables - evChargeking

(ignore the way the link shows as Tesla, although they also do a very neat Tesla pigtail, with the button to open the charge port: Unique Tesla charging cables - evChargeking )

I have a spare, brand new, ~5m longTesla pigtail cable here if you want it. I bought it to fit to our second charge point when I owned a Model 3, but never got around to installing it and have since sold the Model 3.
Superb, thanks for the info
Yeah, if you want to message me the cost for the cable please, it sounds ideal

I now have some cables I no longer need so will look to sell them to offset the cost hopefully...
1 x type 2 to type 2.... 5mtr [Used in my old BMW 330E]
1 x Type 2 to type 1...5mtr [Used in an old Mitsubishi]
and then the cable that will come out of the Rolec, type 1 to open ended 5mtr...

Not sure if we are allowed to offer them on this forum, not checked the forum properly TBH....
 

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I don't think there's any problem selling stuff here, as long as it's just a private sale of EV related stuff. I'll send you a PM, but have just pulled out the box with the cable in and taken some photos that I'll stick here, if only because they may inform others as to what these pigtails look like. The black part on the connector is the special "Tesla button" that sends a remote signal to the car to open the charge port door. It also terminates a charge when pressed whilst it's plugged in, and unlatches the connector from the car.


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