Home charging point- metal in vicinity

[lebelinconnu]

I can't get a straight answer from Octopus so I am hoping someone here can help.
When filling out my application for a home charging unit (MG 5 exclusive LR due to arrive Jan) I came across a question asking me if there is any metal (e.g. outside tap) within 5 metres of the prospective install site for the wall box. I have a tap which would be about 2 metres away- I have attached a photo showing the position of the tap; the wall box would be mounted on the same wall as the door. The form implies that this could be an issue, but I can't work out if this is simply inadvisable or a complete no-no. Octopus insist that I need to finish the application, and I keep trying to tell them that if it's a no-no there is no point, as I can't move the tap so wouldn't be able to have the charge point installed. If anyone can share their wisdom I would be grateful!!

 

[Jomarkh]

Hi, they could be asking incase they need to add an earth rod if you have a TNCS system then you need a rod for PEN protection.

 

[Justin H]

It is because it is a earthed metallic object that is going to be within touching distance of a car that could be installed on a different earthing system. A steel street light would be the same as most of the local distribution networks are PME earthing systems. Chargers that do not detect PEN faults (protective earth neutral conductor) need to be put on a TT system which would most probably be different from your houses earthing system. This is an electric shock risk and would influence what type of charger is installed. Sorry to get too technical.

 

[lebelinconnu]

It is because it is a earthed metallic object that is going to be within touching distance of a car that could be installed on a different earthing system. A steel street light would be the same as most of the local distribution networks are PME earthing systems. Chargers that do not detect PEN faults (protective earth neutral conductor) need to be put on a TT system which would most probably be different from your houses earthing system. This is an electric shock risk and would influence what type of charger is installed. Sorry to get too technical.

So do you mean that I should still be able to get a charge point installed if it is the right type? Apologies, I am as technical as a ton of bricks!

 

[m4rmite]

Surely a water tap just needs to be earth bonded?

 

[Justin H]

So do you mean that I should still be able to get a charge point installed if it is the right type? Apologies, I am as technical as a ton of bricks!

Yes. I'm assuming that your local distribution network will have a combined neutral earth conductor. Therefore if you have a charger that has PEN protection then you would be fine. I personally don't want different earthing systems on my property, or to drive an earth rod into the ground so I went for a Zappi Version 2. I also happen to think it looks the best especially the tethered type where you can wrap the cable around the unit.

 

[Justin H]

Surely a water tap just needs to be earth bonded?

The tap will be bonded (connected to earth) and that's the problem if you introduce a different earthing system. There could be potential voltage difference between the systems that could cause electric shock. If you look on YouTube E-fixx have a demonstration with the bloke from Myenergi. It explains better than me. I think it's under 18th edition amendment 1 or PEN protection.

 

[m4rmite]

@Justin H very interesting, in all the online quotes for an ev charger install they ask for earth bonding on the water and gas pipe.
Regardless of what charger you're interested in.

 

[Justin H]

@Justin H very interesting, in all the online quotes for an ev charger install they ask for earth bonding on the water and gas pipe.
Regardless of what charger you're interested in.

All extraneous metal work in the an installation needs bonding. This connects all metal work together so that in the event of one piece of metal becoming live then all other metal work will be at the same potential (therefore 0 volts potential difference and no shock risk). All this bonding is earthed so it will trip the circuit breaker for the faulty circuit. That's a basic electrical safety requirement. Obviously no will connect anything onto a dangerous electrical installation.

 

[Justin H]

If you look on YouTube this video will give a good explanation.

 

[Lovemyev]

@Justin H very interesting, in all the online quotes for an ev charger install they ask for earth bonding on the water and gas pipe.
Regardless of what charger you're interested in.

Prior to having my wall box installed about 5 years ago now, the owner of the installation company, who is both a fully qualified domestic and commercial electrician, came out to do a survey of our house electrics.
He is a EV driver himself, which helps !.
He did point out that although the water main had been bonded back to the CU when the house as built in the about 1982 - the size of the cable was now under size to regs and to also satisfy the criteria on the form for the grant.
Also, the central heating boiler / copper gas supply pipe had never been bonded.
The boiler had been fitted about ten years after the house was first built and never been picked up.
Both of these bonding items ( paid for by myself ) had to be corrected when the wall box was installed, the following week.
Brilliant when you can get a visual inspection done prior to the install.
It cuts down on issues that maybe only become apparent on the day of the install.
I was lucky, because the guy only lived about 10 miles away from my home address and his company had only just started installing EV wall boxes about 6 months earlier, back on 2015.
He said he would be personally be overseeing nearly every EV install for the first twelve months.
Very professional and responsible boss.
Now in 2021 after his hard work, his company has now grown into a MUCH bigger concern.

 

[lebelinconnu]

Many thanks for all your replies and for the video link, Justin. Much appreciated.