new construction - car charging circuit prep

[gamb00ler]

We're finalizing the electrical circuit plan on our build and my stepson suggested installing a circuit for a car charging port in the garage.

The electrical supply comes into the house in the garage so it should be a simple job.

 

The builder might not know what's required so I would like input from those more knowledgeable than I.

 

How much load should the circuit breaker/wiring be designed to support?

Should circuit breaker be installed now or later?

 

I was planning on the circuit just ending in a junction box but if there is already a standard for the plug I may have it fitted now.

[sometimewoodworker]

13 minutes ago, gamb00ler said:

We're finalizing the electrical circuit plan on our build and my stepson suggested installing a circuit for a car charging port in the garage.

The electrical supply comes into the house in the garage so it should be a simple job.

 

The builder might not know what's required so I would like input from those more knowledgeable than I.

 

How much load should the circuit breaker/wiring be designed to support?

Should circuit breaker be installed now or later?

 

I was planning on the circuit just ending in a junction box but if there is already a standard for the plug I may have it fitted now.

It is a reasonably simple job for an actual electrician. For the average Thai electrical bodger it’s really easy to create an install that can have your car a death trap for anyone or anything that comes into contact with the body of the car.

 

Unless you have someone who actually understands the dangers of doing it wrong, don’t do it. 
 

or as a maximum only run line and neutral into a sealed junction box. 10mm cables will probably be enough.

[Crossy]

For intial prep, run a 10kW (50A) circuit in 10mm² to a junction box near where you want to put the charger.

 

The charger itself will have the relevant instructions as to exactly what you need to put between the charger and the supply.

 

Also ensure you have a 30/100 meter (the installers won't install your home charger on less).

 

EDIT PEA are apparently offering a second 15/45 meter for dedicated EV use where a 30/100 isn't available.

 

EDIT 2 The home charger installation instructions for a GWM (Great Wall Motors) charger, Thai of course. So installing to those requirements should be good to go for most chargers.

 

home-charger-installation-gwm.pdf 

[sometimewoodworker]

One of the extremely important points is NEVER NEVER EVER use you existing earth for the charging point or any point remotely close to your charging point. If you do then a fault can have your car live at line voltage and no in general an RCBO will not trigger before someone touches the vehicle.

 

you must not have any electrical fittings remotely close to the charging point, this includes a light.

 

 

 

 

 

 

Edited March 5, 2022 by sometimewoodworker

[gamb00ler]

7 hours ago, sometimewoodworker said:

It is a reasonably simple job for an actual electrician. For the average Thai electrical bodger it’s really easy to create an install that can have your car a death trap for anyone or anything that comes into contact with the body of the car.

 

Unless you have someone who actually understands the dangers of doing it wrong, don’t do it. 
 

or as a maximum only run line and neutral into a sealed junction box. 10mm cables will probably be enough.

We're using a well-respected builder in CM.  They have built quite a few houses for expats.  They have 22 years of experience building homes.  So far I haven't seem them take any shortcuts.  I am on site for a visit/inspection almost every day.  I find their attitude and the quality work to be very professional.

 

I do appreciate you taking the time to ensure that I know that unskilled workers could create a very dangerous situation.

 

At this point, I'll probably just have them chase the proper sized line into the AAC bricks, cover up with render, install an empty junction box and leave enough extra cable in the consumer unit to hook up a circuit breaker when needed.

 

I have about 500 pictures on Google Drive at: https://drive.google.com/drive/folders/1TZl0zFX_2lk5xOQ_jXofs4zMF7MLffhl?usp=sharing

 

[gamb00ler]

5 hours ago, sometimewoodworker said:

One of the extremely important points is NEVER NEVER EVER use you existing earth for the charging point or any point remotely close to your charging point.

Are you saying the charging circuit requires its own grounding rod that is not close to any other grounding rod?

 

I'll have the builders electrician send me a description/drawing showing the earthing system for our build.

[gamb00ler]

@Crossy I'll pass that PDF along to the architect who speaks excellent English and he'll get it into the proper hands.

[sometimewoodworker]

28 minutes ago, gamb00ler said:

Are you saying the charging circuit requires its own grounding rod that is not close to any other grounding rod?

 

I'll have the builders electrician send me a description/drawing showing the earthing system for our build.

You should watch the videos if you can’t understand then either don’t put in a charging point or find a real electriction who does.

[Crossy]

8 hours ago, gamb00ler said:

Are you saying the charging circuit requires its own grounding rod that is not close to any other grounding rod?

 

I'll have the builders electrician send me a description/drawing showing the earthing system for our build.

 

Yup, your EV charger should be a TT island unless the charge point (and the vehicle) is within the house equipotential zone.

 

Loads of discussions on this subject in various electrical forums but generally giving it its own rod is pretty much guaranteed to be safe.

 

Then along comes a user who plugs the "granny lead" into an outlet in the kitchen ...

 

 

[sometimewoodworker]

13 hours ago, Crossy said:

 

Yup, your EV charger should be a TT island unless the charge point (and the vehicle) is within the house equipotential zone.

 

Loads of discussions on this subject in various electrical forums but generally giving it its own rod is pretty much guaranteed to be safe.

 

Then along comes a user who plugs the "granny lead" into an outlet in the kitchen ...

 

 

That is mostly  correct though missing is that your independent ground rod for the TT island needs to be 5 metres away from all/any other ground point. 
 

Interestingly if you watch the second video you will find that something remarkably similar to a Ufer Ground under, or as part of, the driveway is suggested for grounding EV points in new builds. This gives a sufficiently low resistance, possibly in the low single digits, to allow for something other than a pure TT install.

[Crossy]

Something worthy of note is that the devices mentioned in 722.411.4.1 iii (at 8:14 => in the 1st video) are in fact now available and an increasing number of EV charge points do now incorporate PEN failure detection.