UK EV Charger Earth Rod

[Ben Murray]

I have completed the 2919 course and was told during this that all chargers would require a TT connection, whether solely for the charger or as part of the full installation. Since completing the course a while ago now, I have discussed with some electricians who say they don't install an earth rod when the property is TN-C-S. What is the general view on this?
Also, the instructions for a Tesla charger says it is constantly monitoring for earth faults and over current, switching the charger off and on accordingly, does this mitigate the requirement for an earth rod? Because it is looking out for a lost neutral with a PME system? My argument is the charger could get confused thinking a main bonding conductor was the new supply to earth but we wouldn't deem this OK.

I will always install to what I believe is correct within the BS and the course I completed, but it gets confusing when you hear differing opinions within the trade. I look forward to hearing your views and welcome any suggested previous posts.

I hope everyone coping as well as they can be during the Covid-19 out break and my thoughts are with those who have lost loved ones and those who are struggling financially. Stay safe.

 

[davesparks]

Have done and watched the vid
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Well I would say that he knows a lot more than you do

Marvellous, so you can quote which line in the book states that SPDs are only a recommendation then?

 

[Markyd]

He may do, he may not that’s irrelevant
Obviously your back is up about this so I’ll leave it there.

443.4 overvoltage protection read it bottom section......as I said apology accepted

 

[Ian1981]

443.4 overvoltage protection read it bottom section......as I said apology accepted

Yep does not mention recommendation to a dwelling anywhere
For all other case a RA shall be performed etc etc except for single dwelling units, where the cost of the installation and equipment therin does not justify such protection. So what if it does justify such protection?

Apologies the thread is way off track.

 

[Gavin John Hyde]

If its tns you should enquire with dno to determine if its likely to be upgraded to pme anytime soon.
With pme you need to look at where the charger is being used... For example in a garage linked to house use the supplied PME..
The latest generation of chargers can be safely installed on pme systems without a rod.. Zappi, ANDERSEN, pod Point solo etc... There are options if installing a rod is not practical such as upfront devices.
This is where some people come unstuck as whilst the charger will likely be okay and not be dangerous. All it takes is there to be a fault and a broken Pen conductor and they are up the proverbial creek if somebody gets hurt. Broken Pen conductors are more common than we realise having spoken to a DNO area manager at a recent open forum event in January.
Every EV install is unique, they take some planning to do properly and the risk assessment as per iet best practice guide should always be done.

 

[Markyd]

Yep does not mention recommendation to a dwelling anywhere

Yep does not mention recommendation to a dwelling anywhere

Yep does not mention recommendation to a dwelling anywhere

Yep does not mention recommendation to a dwelling anywhere
For all other case a RA shall be performed etc etc except for single dwelling units, where the cost of the installation and equipment therin does not justify such protection. So what if it does justify such protection?

Apologies the thread is way off track.

Then you recommend one......ta da

 

[Ian1981]

View attachment 56887

Then you recommend one......ta da

No you install one , you don’t recommend!

 

[Markyd]

No you install one , you don’t recommend!

Not if the client says that they don't want one.....it's only a recommendation

 

[Ian1981]

If the Consequences caused by overvoltage for a single dwelling unit where an assessment shows the total value of electrical installation and connected equipment is found to necessitate the cost of SPD protection then you install one, you don’t fob it off as the assessment will have been done with the client.
If it’s found it’s not required then yes don’t install one.

 

[davesparks]

View attachment 56887

Then you recommend one......ta da

It does not say that.
It says that where a risk assessment is not performed an SPD must be installed. With one exception, a single dwelling where the cost of installation outweighs the benefit.

So:
1: If a risk assessment is carried out then you follow whatever the conclusion of the risk assessment is. This does not constitute a recommendation, this is a clear yes or no decision based on calculated risk.
2:if a risk assessment is not carried out you fit an SPD (no mention of recommendation)

The exception to 2 is that IF it is a single

dwelling AND the total value of the equipment that would be protected does not justify the cost of installation then SPD protection may be omitted.
Again a clear yes/no decision based on calculation. This is not a recommendation.

Nothing in the regulations mentions recommendations for SPDs, the requirements are clear-cut yes/no decisions.
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Not if the client says that they don't want one.....it's only a recommendation

If the client says they don't want one, then don't do the job and walk away.
As far as the regulations are concerned you do the job to the regulations or not at all, theres no picking and choosing which bits you want to comply with.

 

[pc1966]

i dont agree with that? Your suppost to eliminate the car shell becoming live should a open PEN conductor occur not wait for someone to have a shock and hope the rcd trips which it wouldnt with the loss of neutral conductor!

Why do we have RCD at all then?

RCD are fitted so there is no single point of failure that leads to a dangerous situation. They are not a substitute for proper insulation of conductors or earth bonding of metalwork, but are there to deal with cases when something unlikely but possible results in a dangerous situation (e.g. open PEN conductor, garden tool cuts extension lead, etc).

True if you lost the majority of L-N voltage it would not be able to trip but I suspect you would see a fair portion of 230V remaining due to the other phases' loads. If designing something like this from scratch you would probably have something like the Matt:e box contactor that would zero-volt release under such circumstances, and possibly only close fafter doing a self-test cycle.

 

[hasel5]

Had a call out yesterday to a Car Charger not working Power supply on to unit.
When car plugged in went to fault straight away.
On investigation found the earth rod on the house supply had a sheared nut in the earth pit leaving a very high earth loop.

If the car Charger had not picked up this issue the people in the house would of never known the nut was sheared.

Just my Thoughts

 

[pc1966]

If the Consequences caused by overvoltage for a single dwelling unit where an assessment shows the total value of electrical installation and connected equipment is found to necessitate the cost of SPD protection then you install one, you don’t fob it off as the assessment will have been done with the client.
If it’s found it’s not required then yes don’t install one.

Given that separate Type 2 SP+N SPD can be bought for under £100 and you can get whole CU with them already included for around £100-£150, why both with the risk assessment at all?

I suspect doing it properly and documenting it for the client is going to cost more than £100 of your time!

 

[Ian1981]

Given that separate Type 2 SP+N SPD can be bought for under £100 and you can get whole CU with them already included for around £100-£150, why both with the risk assessment at all?

I suspect doing it properly and documenting it for the client is going to cost more than £100 of your time!

I install them as standard in domestic

 

[bigspark17]

No spd required.......it's only a recommendation to have one and I believe you have to do a course to get a qualification to fit car chargers

i believe you only have to have the qualification and manufacturer ev charger approved if you want to be olev registered. If not a EIC will suffice.
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Why do we have RCD at all then?

RCD are fitted so there is no single point of failure that leads to a dangerous situation. They are not a substitute for proper insulation of conductors or earth bonding of metalwork, but are there to deal with cases when something unlikely but possible results in a dangerous situation (e.g. open PEN conductor, garden tool cuts extension lead, etc).

True if you lost the majority of L-N voltage it would not be able to trip but I suspect you would see a fair portion of 230V remaining due to the other phases' loads. If designing something like this from scratch you would probably have something like the Matt:e box contactor that would zero-volt release under such circumstances, and possibly only close fafter doing a self-test cycle.

no this is does not mean fitting an rcd will cover the open PEN fault. You contradicting yourself in your post, yes a contactor will satisfy this requirement hencr the 1st amendment.
have you fitted an ev charger on a pme relying on this two rcds in series theory??

 

[Mike Johnson]

On investigation found the earth rod on the house supply had a sheared nut in the earth pit leaving a very high earth loop.

The Bolt shearing in an earth rod installation is a very common occurrence in the South of France where the extremes of temperature cause expansion contraction fatigue, this type seem to be more reliable: 14mm ( 5/8" ) Cast Earth Clamp - https://www.tlc-direct.co.uk/Products/TLEC58.html using them to clamp the cable to the rod.