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Zoe ZE50 GT Line R135
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Discussion Starter #1
Can anyone recommend an earth rod-free home charge point, for use with an OHME cable?

I've had one quote for a tethered OHME charge point of £530 (after grant), based on photos and video I uploaded.

Qualifying for the grant may be tricky and time consuming. I would have to go for a six month Evezy rental (which I don't really want), and I'm converting the front garden to off street parking. The sequencing of that seems slow. (I'll have to get the paving done, and only then can I ask the council to install a drop kerb, and only then can I qualify for the OLEV grant).

A local friendly electrician suggested doing all the cabling internally and going for a charger that doesn't require an earth rod. That can also use a spare way in the existing consumer unit, where an externally-earthed point would require a dedicated consumer unit.
 

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If you want an Ohme cable, why, at least initially, do you want a charge point?
A "Commando" socket could safely be fitted with appropriate wiring to provide you with a means of connecting the Ohme unit. Later, when everything is in place you could swap to a conventional charge point (either with an Earth rod or without such as a Zappi) and claim the OLEV grant. At that point you would need to swap the Ohme cable for one with a Type 2 socket rather than a Commando but you are unlikely to lose much selling the original.
 

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Zoe ZE50 GT Line R135
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Discussion Starter #3
Ooh hadn't thought of that. A 7kW one?

It would still require a dedicated circuit though? Is there anything I should be aware of when getting the electrician to install it (in terms of the RCD protection etc) to prevent any problems when I come to upgrade?

Ideally, what I would like is a tethered OHME, or something as smart as it.
 

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It would still require a dedicated circuit though? Is there anything I should be aware of when getting the electrician to install it (in terms of the RCD protection etc) to prevent any problems when I come to upgrade?
7kW will always need its own circuit.
Just get the spark to fit a 32A RCBO in a spare way to feed the 32A commando socket.
When (if) you upgrade later then the OLEV installer can decide if he needs to fit a separate CU, earth rod, etc, depending on how equipment and regs have changed to that point - both seem to be evolving at present.
 

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Zoe ZE50 GT Line R135
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Discussion Starter #5
Brilliant, thanks. Looks like this could be an easy cheap and effective solution!

Does the earthing question simply go away if I fit a Commando socket? Whatever I plug into it, just has to accept the earth I already have?

(And I mean that both in terms of regs and practicalities of a potentially fussy car)
 

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You are going to Level 2 charging, like a "granny" lead, only faster. As you say the potential issues are having a car that is sensitive to Earth resistance (aka the socket tester on wheels, the Zoë) and in theory if your PME Earth at the substation breaks.
Is there a reason why you don't want an Earth rod now? It will require a separate consumer unit but prepares you for the eventual OLEV solution if current rules remain in force.
 

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The last revision to the Wiring Regulations require that any mains outlet intended for electric car charging should have an earth connection that is independent of the house (PME) earthing because of a perceived risk of someone getting an electric shock if they are standing on the ground touching your electric car when at the same time there is a break in the combined Neutral/Earth conductor of your incoming supply.

[An acceptable alternative is that there should be a device (possibly within the chargepoint) that, if there is a voltage difference of greater than 70 volts for more than 4 seconds between the house earth and the ground local to your electric car, disconnects all conductors (including the house earth) on the supply to the electric car, and requires a manual reset].

As you are converting part of your garden into a car parking space, now is the easy time to bury a length of earthing tape underneath your car parking space (preferably in damp soil) before you get the paving done, rather than having to try installing an earthing rod(s) at a later date.
 

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Zoe ZE50 GT Line R135
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Discussion Starter #8
No particular reason that I don't want an earth rod. Just that the electrician suggested it would be a lot cheaper without one (subject to the difference in cost of the charge point that meets the requirements). Not just the rod itself, but the associated extra work at the supply.

Would earthing tape be a cheaper/ better solution than rods?

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One (final) question. Is it worth putting larger cable than required for 32A? I don't think the regs allow charging at, say, 45A currently (?), but the Zoe can handle it and so can my main fuse. Possibly future changes in the regulations might allow it?
 

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Is there a reason why you don't want an Earth rod now? It will require a separate consumer unit but prepares you for the eventual OLEV solution if current rules remain in force.
Why does it require a separate CU?
AIUI separate CUs are fitted either because of a lack of spare ways or because it's easier for the installer. I don't think there is any regulation requiring it - the live and neutral are coming from the same supply regardless, you are just using a separate earth.
 

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If you don’t want a rod, the two charge points that claim not to necessarily need one are the Zappi and the Pod Point. However if using the matt:E device you should be able to expand your choice to using any charging point.
 

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Why does it require a separate CU?
AIUI separate CUs are fitted either because of a lack of spare ways or because it's easier for the installer. I don't think there is any regulation requiring it - the live and neutral are coming from the same supply regardless, you are just using a separate earth.
My understanding, possibly incorrect is that you can't have two different Earth's in a single CU.
One (final) question. Is it worth putting larger cable than required for 32A? I don't think the regs allow charging at, say, 45A currently (?), but the Zoe can handle it and so can my main fuse. Possibly future changes in the regulations might allow it?
I think that your Zoë is limited to 7kW per phase but stand to be corrected. Personally I think that it is worth fitting thicker cable but more to potentially allow 2 EVs in the future.
 

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I think it was something to do with the existing RCD potentially being damaged by DC leakage, but I may have that wrong. It's well beyond my knowledge!
If the chargepoint is fed from a 'house' RCD then that may be 'blinded' by DC leakage. The chargepoint should be separated from that and use it's own protection.
For the commando socket the same can be applied - an RCBO is the simplest way to do it.
The bigger problem is often that rearranging the CU to do this gets tricky, and it all has to be retested after the shuffle. So the separate CU option can be a cheaper/easier route when you are paying £40-£50 an hour in labour.

My understanding, possibly incorrect is that you can't have two different Earth's in a single CU.
But you don't. If you have a separate earth rod then assuming it's an armoured cable the armour will be connected to the earth at the CU end but insulated at the far end. The live and neutral are obviously connected at both ends but the far end earth is connected to the earth rod only.
 

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Zoe ZE50 GT Line R135
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Discussion Starter #14
Thanks for the suggestions. Local spark is installing a 32A Commando socket next week, and the oHME cable is on order. Official paving of the garden will take longer, but in the meantime, I can just go at the wall with a sledgehammer and park on the grass.

Can anyone point me in the direction of a 32A Commando > 13A adapter, to allow me to use normal garden tools etc in the socket? I've seen plenty of 16A > 13A adapters for a few quid, but can't for the life of me find one to fit a 32A socket.
 

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EVBitz will build one for you for around £30, or you can build your own from parts from somewhere like toolstation. Or your Sparky could custom make one.
 

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Zoe ZE50 GT Line R135
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Discussion Starter #16
‘Next week’ took a while due to Covid, but finally got the socket installed this morning.

Just need some movement from the driveway people, the smart meter installation, the main fuse upgrade, the dropped kerb from the council... oh yeah, and the car!
 

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Don't want to put a downer on your plans but the lack of an earth may cause problems when you come to sell the house as it will not meet the wiring regulations. Next, if you don't have a dropped kerb the council may fine you for driving over the pavement.
 

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Zoe ZE50 GT Line R135
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Discussion Starter #18
Dropped kerb will go in when the council feel like it! And they won't come and do it till after the drive is paved. To be fair, they seemed to think they'd be pretty quick once I call them.

There's no earth rod specifically for the socket, but there is one for the house as my wiring is TT. Spark suggested that this would meet wiring regs. In any case, I'll probably be upgrading to a proper EV charger at some point in the future, with or without an earth rod as required.
 

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Renault ZOE R135 ZE50 GTLine July 2020 (Sold: R90 ZE40 i Dynamic Nav June 2017)
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as it will not meet the wiring regulations
The 18th Edition regs have been updated to specify ways in which an EVSE can be installed without an earthing rod. Some EVSE's already meet the regs.

Edit: see this post for links to good explanatory videos: Earth rod alternatives

And other posts in the rest of that thread.
 
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