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EV charger installation question – I don't want to bury the cable

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Transparent
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Thanks @hem 

HemMeterbox

That looks like a SMETS1 meter with an Elster (Honeywell) Communications Hub operating at 900/1800MHz for connection to the National Smart Meter Network operated in the southern and central territories by Telefonica.

I like the inclusion of a separate 100A 2-pole isolation switch.
That allows an electrician to work safely within your consumer unit, without needing to break the seal on the Service Fuse.

I dislike what looks like a whole-house residual current detector (RCD) in that location.
Any earth-leakage fault within the house electrics will cause that trip to open, thereby plunging everyone into darkness. Ugh!
You then need to correct the fault, before going outside with a meter-box key to reset the trip. That's unfriendly.

Since your house is supplied from a PME substation, your EV charger must have its own earth stake rather than being connected back to the house earth-block.
The house earth is being provided by a link to the Neutral incomer to the property.

EV Earth types

 

Cars have metal bodies.

In the event of a broken neutral wire between your house and the substation transformer, it's essential that the metalwork can't 'float' upwards.
That would present a shock hazard to anyone touching the car.

ChargerEarthingB

There are 550,000 substations in Britain.
Each year about 300 of these have a neutral fault which requires the DNO to repair it.

So you need to check with PodPoint whether they'd accept a 2-core SWA cable.
The armour would still be connected to earth at the house end to protect against cable damage.
But it wouldn't connect to anything at the garage end.

This post was modified 4 weeks ago by Transparent

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 Hem
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@transparent 

Thank you once again.

Message from podpoint

"For areas where the cable crosses a path or a garden, we require the cable to be laid underground in ducting..

When organising the works, please ensure they follow the full specifications below:

  • The trench needs to be a minimum depth of 450mm except for driveways where depth should be at least 600mm.
  • There needs to be continuous twin walled flexi-duct with a minimum diameter of 50mm for the entirety of the underground run.
  • A 6mm - 9mm nylon rope (draw cable) for cable pulling is expected to be installed in all ductwork for current cabling AND future use/capacity.
  • Yellow warning tape to be placed in trench before being filled in.
Please let us know how you’d like to proceed "
 
I can check about 2-core SWA cable only tomorrow..
Regards
Hem

   
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(@ianmk13)
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@transparent   If it's a Podpoint Solo EV charger, a quick look at the installation guide suggests it has has a form of PEN fault detection and can be connected to a TN-C-S supply without need of a separate earth electrode.

@hem  Again, if it's a Podpoint Solo EV charger, there doesn't appear to be a wired network option so you will need good WiFi coverage at the front of the garage.  A low voltage two-wire connection back to a current transformer on the incoming grid live supply will also be required, so a cable with integral cat5 core will be useful.  At that distance, I would choose the 6sq mm version. Your electrician will need to register the installation with your DNO and building control.


   
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Transparent
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Posted by: @hem

For areas where the cable crosses a path or a garden,

It's not 'crossing' a path or garden except for one point near the back door.

The intended cable-run is mainly along a fence...
which we don't yet know whether you own.

HemPlanA

We only have a plan view to go on, and a photo of the pathway near your back door might help.

I can't see why a cable can't cross between the house and the fence at high level (say 2.5m above the path).
The fence may require a post to be extended upwards. But that could be done using a piece of aluminium angle.
I'd be paying more attention to how the SWA cable gets attached as it crosses that back path.

A thin stainless-steel wire rope could provide the required support.
Go to Amazon and type in Steel Wire Kit; there's loads of possibilities.

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 Hem
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@transparent 

It is Podpoint Solo3 indeed. 

Thanks once again. much appreciate your help.


   
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 Hem
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@transparent 

I found this on outer wall of garage..looks from main power supply.

20240518 124620
20240518 124610

 Can EV charger can be installed via this?

thanks


   
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Transparent
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Hmmm...

That raises a lot of questions in my mind!

1: The Steel Wire Armoured (SWA) cable size needs to be known.
What does the white writing say on the outer black sheath below the junction box?

2: Have you located the other end of that SWA cable within the house?
It may not be derived from the main consumer unit.
It could equally be a spur from a ring main.... which should have a fuse, but may not.

3: What do the brown and blue wires supply inside the garage?

4: We don't like screwed terminal strips any more(!). But that 3-way could readily be replaced by three 2-pole WAGO connectors.

 

You're not going to be able to run a 7.5kW charger from that SWA cable anyway.
It would need to be around 6mm² for that.

But you might still be able to draw 16A, depending on the conductor size and where the house-end connects.

I have a 32A 3-pin round blue connector for my EV, with no actual charger at all.
There is a 16A equivalent which you could consider.

32AsktcropSm

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 Hem
(@hem)
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@transparent Thank you for your reply. It's going to be difficult to find the other end. That unit on the garage wall is in neighbours garden 🙄


   
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Transparent
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So whose electricity is passing through that junction box?

What socket (or light) does it feed within your garage?

Which of the trips in your consumer unit render that socket 'dead'?
Any of them?

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 Hem
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@transparent I checked, Electricity is going through our power supply and the fuse pic attached.

In garage it is connected to plug socket and to a bulb. I have checked the trip too. Pic attached.

Thanks,

Hem


   
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 Hem
(@hem)
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 I checked, Electricity is going through our power supply and the fuse pic attached.

In garage it is connected to plug socket and to a bulb. I have checked the trip too. Pic attached.

Thanks,

Hem

20240519 153739
20240519 154309
20240519 153710

 


   
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Transparent
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The fact that the MCB is rated 16A tells us what we need to know.

If you were sure to use no garage light or socket at the same time, then you'd be able to draw 16A for the EV.
Unless you have any other evidence that the SW cable is larger than 1.5mm² then you shouldn't increase the rating of the MCB.

There's a cable-size calculator here on the TLC Direct website which can 'play' with to see what's possible.

Save energy... recycle electrons!


   
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