V2L Earthing - how?

[TschZS]

I cannot seem to find any clear answer on this. How, if at all, does the V2L system provide an earthing system? There is no actual connection to earth, but does it need one?

I’ve read there is some form of in built RCD but I’ve also read no such thing exists. Is an RCD even needed if it is a totally isolated IT type system where the neutral is not ‘earthed’ and thus touching a live conductor wouldn’t allow current to flow through you to earth?

Anyone in the know who knows how the system works, your views would be appreciated.

 

[Nicko]

I am an electrical engineer and I totally agree with your statement. If an RCD was fitted it would have to have the function to be reset and tested? I have looked for the answer and I cannot find one. Still looking?

 

[Jomarkh]

Most V2L are just type2 to a 13A socket for a kettle.
If you mean V2H or V2G then that is a totally different setup.

 

[TschZS]

Most V2L are just type2 to a 13A socket for a kettle.
If you mean V2H or V2G then that is a totally different setup.

I think you misunderstand why question. Where is the earthing pin in the V2L receptacle via the PE pin in the type 2 connector actually earthing to?

 

[Nicko]

If there is a fault on the socket or appliance and say a toaster becomes live on the exposed metal part, if you touch that metal it will use you as an earth and you could have a shock. On any electrical circuit you should have full protection i.e. minature circuit breaker (MCB), Residule current device (RCD) etc just like you have in the house

 

[N2STY]

If there was contact with PE\CPC and N or L1 the car stops supply untill restart of the load process
(Same applies to L2 L3 if in use)

 

[TschZS]

If there is a fault on the socket or appliance and say a toaster becomes live on the exposed metal part, if you touch that metal it will use you as an earth and you could have a shock. On any electrical circuit you should have full protection i.e. minature circuit breaker (MCB), Residule current device (RCD) etc just like you have in the house

Is this correct in an isolated IT type supply, though? Keep in mind that a V2L system is ‘floating’. The neutral is not earthed. Electricity will only want to flow to earth if the neutral is also earthed in order to complete a circuit, such as in a grid based MEN system. In a totally isolated system, where neutral is not earthed, touching the live conductor and also standing on the ground should not cause current to flow through you as the earth does not lead back to the neutral source. Touching the car, however…

If there was contact with PE\CPC and N or L1 the car stops supply untill restart of the load process
(Same applies to L2 L3 if in use)

Isn’t the PE also N bonded ?

 

[N2STY]

Isn’t the PE also N bonded ?

I don't believe so it works the same as rcbo
Edit it is possible it's linked

 

[TschZS]

I don't believe so it works the same as rcbo

How would an RCD detect an imbalance without a reference to ground for the current to flow?

 

[N2STY]

How would an RCD detect an imbalance without a reference to ground for the current to flow?

Because what goes out L1 has to come back in N any imbalance stops the power

 

[TschZS]

Because what goes out L1 has to come back in N any imbalance stops the power

Yes but L1 will only travel to earth if earth completes the circuit. Remember. In a V2L system, it does not have a multiple earthed neutral (MEN) system as it is floating/isolated. So if I touch the L1, why would it flow through me if I do not complete the circuit to N? And therefore, why would the RCD trip?

 

[Nicko]

An RCD operates by having a ct on the live and one on the neutral monitoring the magnetic flux of each conductor. If neutral or live go to earth it senses the in-balance and trips. So you are now the earth to create an in-balance.

 

[TschZS]

Because what goes out L1 has to come back in N any imbalance stops the power

The reason an RCD trips in your home if you touch a live conductor is because the neutral is earthed at multiple points not just on your home but throughout the grid. Electricity in a MEN system will want to travel to earth if you touch it as it completes the circuit, but in an isolated system where neutral is not earthed, electricity will not want to flow to actual earth as it does not complete the circuit.

An RCD operates by having a ct on the live and one on the neutral monitoring the magnetic flux of each conductor. If neutral or live go to earth it senses the in-balance and trips. So you are now the earth to create an in-balance.

Yes but that requires electricity to want to flow to earth. In an isolated system, electricity will not flow to earth if the neutral conductor itself is not earthed

An RCD operates by having a ct on the live and one on the neutral monitoring the magnetic flux of each conductor. If neutral or live go to earth it senses the in-balance and trips. So you are now the earth to create an in-balance.

This may explain better: https://powersafe.net.au/wp-content/uploads/2020/06/Powersafe-RCD-DUO-Safety.pdf

 

[Nicko]

The neutral earth connection is done back at the DNO transformer at the star point. We do not connect neutral to earth after this?

 

[TschZS]

The neutral earth connection is done back at the DNO transformer at the star point. We do not connect neutral to earth after this?

On a grid system? In Australia it’s at the source, delivered via wire, and earthed at multiple points through the grid (and we also earth stake at the home)

 

[Nicko]

See attached link, you are now the earth to cause an imbalance between the L and N to trip the RCD.

https://electrical-engineering-portal.com/how-residual-current-device-rcd-works

 

[N2STY]

RCBOs do not have to have a separate earth connection to meet the standard EN61009.

 

[TschZS]

See attached link, you are now the earth to cause an imbalance between the L and N to trip the RCD.

https://electrical-engineering-portal.com/how-residual-current-device-rcd-works

That article discusses an RCD working within a Multiple Earthed Neutral system, the most common grid connected system. Remember, a V2L system is not neutral-earthed, it is isolated, so that article does not apply to V2L systems.

 

[Alb]

There is more than one earthing protocol in the UK. See this video for an explanation:

 

[TschZS]

RCBOs do not have to have a separate earth connection to meet the standard EN61009.

No, but electricity will flow any way to complete its circuit. Do you know why your home electrical system will flow to ‘earth’ if you touch it? It’s because the neutral conductor, which completes the circuit, is earthed at multiple points in the grid, including probably your earth stake at home; but also at multiple points along the poles and wires from the source to your house. This is why when you touch a live conductor, the electricity will ‘want’ to flow through you to earth. When this occurs, the RCD detects an imbalance between the home neutral and live, and disconnects. In an isolated system, such as V2L or a generator, where there is no earthed neutral, touching the live conductor will not cause electricity to flow through you as the earth does not complete the circuit back to the source (the V2L source or generator), so a RCD won’t work because there will be no imbalance. So. How would a RCD work in this case if electricity won’t flow through you to earth?