EV Charger

[Tomosmorris94]

I have just installed my first EV Charger yesterday. I have installed using a 6mm twin from the non RCD side of the consumer unit on a 32a type b MCB. The length of run is around 5 metres and is contained in 20mm round conduit.

The charger I have fitted is a Rolec with a built in type A 30mA RCBO. I have installed an earth rod below the charger as I was told EV chargers can rely on the earth of a TNC-S system.

Upon testing j had a reading of 347 ohms on my Rod and 24.8ms on my RCD. my question is, would this be sufficient as it is protected by a 30mA RCBO therefore the maximum reading permittable is 1667ohms or am I wrong and does it have to be below 200ohms?? 50volts (touch voltage / 0.03 = 1666.66.

Thanks guys! Go easy, this is my first post!

 

[Gavin John Hyde]

I have just installed my first EV Charger yesterday. I have installed using a 6mm twin from the non RCD side of the consumer unit on a 32a type b MCB. The length of run is around 5 metres and is contained in 20mm round conduit.

The charger I have fitted is a Rolec with a built in type A 30mA RCBO. I have installed an earth rod below the charger as I was told EV chargers can rely on the earth of a TNC-S system.

Upon testing j had a reading of 347 ohms on my Rod and 24.8ms on my RCD. my question is, would this be sufficient as it is protected by a 30mA RCBO therefore the maximum reading permittable is 1667ohms or am I wrong and does it have to be below 200ohms?? 50volts (touch voltage / 0.03 = 1666.66.

Thanks guys! Go easy, this is my first post!

Tidy install with the conduit etc Not a fan of Rolec units myself as the quality is not there, if getting into the EV game start with some other brands. for £60 more you can get a zappi and the hub if going down olev route from the main suppliers and dont need an earth rod or upfront RCD. so much better in terms of quality and features.

Personally I wouldn.t be happy with a reading that high on an earth rod, If ground conditions permit I would look to get it in a lot deeper (use an sds attachment to drive it in ) or add additional rods. if not possible then the Matt: devices or the Garo alternative would be my go to device.

As mentioned some Renault EVs throw a tantrum on anything over 100 ohms. so bear this in mind.

The EV game is getting quite strict now on risk assessments and pre works surveys, NAPIT will soon be looking to inspect an ev charger install on annual assessments for those involved in the sector, have heard rumours NICEIC will be following suit, if you install chargers then they will ask to see one on the annual assessment either instead of or in addition to other work. as a lot of people are installing them with no regards for the condition of the existing install or risk assessments. OLEV are now asking for additional documents and wont be long before they ask for the pre install site survey to be documented and submitted along with DNO forms etc. I am all for it as I have seen some truly horrific installs, In one case

 

[HappyHippyDad]

I have just installed my first EV Charger yesterday. I have installed using a 6mm twin from the non RCD side of the consumer unit on a 32a type b MCB. The length of run is around 5 metres and is contained in 20mm round conduit.

The charger I have fitted is a Rolec with a built in type A 30mA RCBO. I have installed an earth rod below the charger as I was told EV chargers can rely on the earth of a TNC-S system.

Upon testing j had a reading of 347 ohms on my Rod and 24.8ms on my RCD. my question is, would this be sufficient as it is protected by a 30mA RCBO therefore the maximum reading permittable is 1667ohms or am I wrong and does it have to be below 200ohms?? 50volts (touch voltage / 0.03 = 1666.66.

Thanks guys! Go easy, this is my first post!

Hi Tomos. Can I ask if this is PME? You have said you have installed an earth rod because EV charges can rely on the earth of a TNCS which i dont quite understand. Did you mean 'couldn't rely' on earth of the TNCS?

Also, where have you actually terminated the earth cable you have installed. In the charging unit? If so, wouldn't that be classed as utilising note (ii) of regulation 722.411.4.1 which means you would have to get the Ra much much lower (in reality you would not be able to get it low enough without multiple earth rods as it needs to be around 1ohm).

 

[Doomed]

Look at Pod Point chargers in future - no rods needed

 

[Tomosmorris94]

Tidy install with the conduit etc Not a fan of Rolec units myself as the quality is not there, if getting into the EV game start with some other brands. for £60 more you can get a zappi and the hub if going down olev route from the main suppliers and dont need an earth rod or upfront RCD. so much better in terms of quality and features.

Personally I wouldn.t be happy with a reading that high on an earth rod, If ground conditions permit I would look to get it in a lot deeper (use an sds attachment to drive it in ) or add additional rods. if not possible then the Matt: devices or the Garo alternative would be my go to device.

As mentioned some Renault EVs throw a tantrum on anything over 100 ohms. so bear this in mind.

The EV game is getting quite strict now on risk assessments and pre works surveys, NAPIT will soon be looking to inspect an ev charger install on annual assessments for those involved in the sector, have heard rumours NICEIC will be following suit, if you install chargers then they will ask to see one on the annual assessment either instead of or in addition to other work. as a lot of people are installing them with no regards for the condition of the existing install or risk assessments. OLEV are now asking for additional documents and wont be long before they ask for the pre install site survey to be documented and submitted along with DNO forms etc. I am all for it as I have seen some truly horrific installs, In one case

Thanks mate! I think I will be putting another rod in, with a threaded end so I can attach another rod to drive it down deeper. I will get the reading down to below 200ohms! The car being charged is a BMW i3 ?

I have been made aware of rolec chargers not being the best on the market, but this one was supplied by the customer.

Thank you for your feedback mate. I will let you know how I get on ?

 

[Tomosmorris94]

Hi Tomos. Can I ask if this is PME? You have said you have installed an earth rod because EV charges can rely on the earth of a TNCS which i dont quite understand. Did you mean 'couldn't rely' on earth of the TNCS?

Also, where have you actually terminated the earth cable you have installed. In the charging unit? If so, wouldn't that be classed as utilising note (ii) of regulation 722.411.4.1 which means you would have to get the Ra much much lower (in reality you would not be able to get it low enough without multiple earth rods as it needs to be around 1ohm).

Hi mate. Yes I was meant to put cant rely on the earth of a TNCS system. I have terminated the earth cable from the earth rod to the earthing terminal within the car charger. The earth coming from the installation i have put in a Wago but connected the earth at the house end so the supply cable is protected.

 

[HappyHippyDad]

Well I'm confused now then. Note ii specifically refers to the earth rod being connected to earthing bar in the EVCP. In the event of PEN break there would be potential between the car and any extraneous conductive parts (unless the Ra meets the requirements of note ii).

 

[Gavin John Hyde]

Another thing to consider is proximity of exposed metal work earthed by the house supply in relation to the chargepoint such as water and gas etc. That meter cabinet could indicate a few services in the ground nearby so go careful banging the rods in!
Whilst the socket below isn't metallic the items plugged in could be class 1 devices.
Whilst unlikely you then have possibility of different potentials in fault conditions or when car is charging and something plugged.

 

[Welchyboy1]

Out of interest where abouts are you? I am in east England and as long as I can get a 1meter rod into good old Essex clay the readings are always around the 20ohm scale

 

[Welchyboy1]

Another thing to consider is proximity of exposed metal work earthed by the house supply in relation to the chargepoint such as water and gas etc. That meter cabinet could indicate a few services in the ground nearby so go careful banging the rods in!
Whilst the socket below isn't metallic the items plugged in could be class 1 devices.
Whilst unlikely you then have possibility of different potentials in fault conditions or when car is charging and something plugged.

That’s exactly what I was going to say especially about the socket below
I think I would just fit a pen relay as standard, too many potential problems with using rods
Or chargers that allow pme supplies

They will all have to eventually, it’s just too problematic otherwise

 

[Tomosmorris94]

Out of interest where abouts are you? I am in east England and as long as I can get a 1meter rod into good old Essex clay the readings are always around the 20ohm scale

Did you only tt the charger or the whole property?

I'm in North Wales, this particular installation is in Rhos on Sea, North Wales. The TT system is only protecting the car charger ?

 

[Welchyboy1]

I'm in North Wales, this particular installation is in Rhos on Sea, North Wales. The TT system is only protecting the car charger ?

I should imagine it’s very rocky ground similiar to Cornwall unfortunately not good for rodding

In future I would probably insist on using pme friendly chargers maybe? Save you the headache!

Nice tidy looking install tho ?

 

[Tomosmorris94]

I should imagine it’s very rocky ground similiar to Cornwall unfortunately not good for rodding

In future I would probably insist on using pme friendly chargers maybe? Save you the headache!

Nice tidy looking install tho ?

Thanks mate! Yess I will use PME friendly chargers next time, like zappi?? This specific install, it was for someone I know and they had supplied the charger. I know for next time! ?