Can I use VOELCB as Main isolation switch

[Stuart981]

I haven't read the whole thread, but -

to find earth leakage, the Line and Neutral of various circuits are clamped; not the CPCs(earth wires) or bonding conductors.

You need to find out where the earth leakage is originating, not where it is going.

Thanks for the reply. I've unplugged everything that can be unplugged and still seeing around 100mA when clamping at the meter tails but haven't had a chance to delve deeper at this time. Just wondering if moving the main earth from the spike in the ground to the water pipe, as a temporary measure, might improve safety.

Regards Stuart

 

[EFLImpudence]

No.

 

[flameport]

Just wondering if moving the main earth from the spike in the ground to the water pipe, as a temporary measure, might improve safety.

No.
Disconnecting the main earth to an installation will not improve anything. It's very likely to make it unsafe.
Water pipes cannot be used as the earth for any installation.

still seeing around 100mA when clamping at the meter tails

On it's own, that means nothing.
From the previous problems with the RCD, there are one or more faults within the installation.
Those need to be found and repaired.
Messing about with the earth and bonding connections will not fix anything.

 

[Stuart981]

I haven't read the whole thread either but he started this in late January. He has emphatically been told that he cannot use the VOELCB in his installation, yet he continues to ask more and more questions pertaining to trying to use it at this current time.

To the OP, @Stuart981, are you going to accept that this device is functionally useless and your playing around with it actually constitutes a danger to yourself and your family?
Your wiring needs to be updated as a matter of concern and you will have to accept the fact that you need to have it done professionally as soon as possible. This is not like playing about with a board & switches etc in a college lesson using extra low voltage equipment. This is playing about with a 'real world' situation where you, or others, could be seriously hurt or killed.

No.
Disconnecting the main earth to an installation will not improve anything. It's very likely to make it unsafe.
Water pipes cannot be used as the earth for any installation.


On it's own, that means nothing.
From the previous problems with the RCD, there are one or more faults within the installation.
Those need to be found and repaired.
Messing about with the earth and bonding connections will not fix anything.

Thanks for the reply

My understanding is that a fault current will always take the best route to earth that is available.

So, if you had a situation where a fault current is earthing by an alternative route, like a rising water main, then does it follow that the designed earth route would be able to conduct the fault current to earth if that alternative route was removed.

For example, if a plastic insert was to be introduced into the water pipe would the fault current then use the designed earth route or are you likely to end up with no earth at?

Regards Stuart

 

[JohnW2]

My understanding is that a fault current will always take the best route to earth that is available.

The fault current will be shared between all the available paths to earth, proportionately more in those routes which are 'better' (lower impedance).

So, if you had a situation where a fault current is earthing by an alternative route, like a rising water main, then does it follow that the designed earth route would be able to conduct the fault current to earth if that alternative route was removed.

As above, if one of the paths to earth is removed, then all the fault current obviously has to flow through remaining routes. However, what you may be missing is that the magnitude of the fault current will depend upon 'how good' (low impedance) the available path(s) to earth - if itvis a 'very high' impedance, then the fault current will become 'very low' .... so ....

For example, if a plastic insert was to be introduced into the water pipe would the fault current then use the designed earth route or are you likely to end up with no earth at?

If the 'designed earth route' did not provide a path to earth of low enough impedance, then that earth would be 'inadequate' as an earth, and therefore not 'safe'. What you need to understand that, for an earth to be effective ('safe') a high fault current is a 'good thing', and that the fault current will become low if the path to earth is of high impedance.

Kind Regards, John

 

[Stuart981]

The fault current will be shared between all the available paths to earth, proportionately more in those routes which are 'better' (lower impedance).

As above, if one of the paths to earth is removed, then all the fault current obviously has to flow through remaining routes. However, what you may be missing is that the magnitude of the fault current will depend upon 'how good' (low impedance) the available path(s) to earth - if itvis a 'very high' impedance, then the fault current will become 'very low' .... so ....

If the 'designed earth route' did not provide a path to earth of low enough impedance, then that earth would be 'inadequate' as an earth, and therefore not 'safe'. What you need to understand that, for an earth to be effective ('safe') a high fault current is a 'good thing', and that the fault current will become low if the path to earth is of high impedance.

Kind Regards, John

Thanks for your very clear explanation John. I guess to test that is going to be way beyond the capability of my ten quid multimeter.

 

[EFLImpudence]

If that is all you have, how did you measure the 100, 30 and 1mA.?

 

[EFLImpudence]

Oh, I see you borrowed the correct meter. Borrow it again?

 

[bernardgreen]

My understanding is that a fault current will always take the best route to earth that is available.

The fault current will divide up into several currents and these will take every available route to Earth, The "best" route will carry most of the fault current and the worse route to Earth will carry a small portion of the fault current

 

[conny]

And the danger of all these 'separate' low routes is that, if someone comes into contact with one, (or more), of them, then they could potentially create a 'good' route and receive the full fault current through their body.

 

[Stuart981]

Oh, I see you borrowed the correct meter. Borrow it again?

Would that enable me to determine if the earth route through the spike in the ground is is performing to specification?
Regard Stuarts

 

[Stuart981]

And the danger of all these 'separate' low routes is that, if someone comes into contact with one, (or more), of them, then they could potentially create a 'good' route and receive the full fault current through their body.

I know all the water pipes in the house were bonded together in the attic when a shower was fitted. Would that mitigate the risk?

 

[EFLImpudence]

Would that enable me to determine if the earth route through the spike in the ground is is performing to specification?
Regard Stuarts

No, you need at least an Earth Fault Loop Impedance meter for that.

You need to determine - with the leakage meter - which circuit the earth fault is on and then find it.

 

[JohnW2]

And the danger of all these 'separate' low routes is that, if someone comes into contact with one, (or more), of them, then they could potentially create a 'good' route and receive the full fault current through their body.

You seem to be making the same mistake as Stuart, in assuming that the 'fault current' is a fixed entity whereas, in reality, it is totally dependent on the impedance of the path to earth.

If the only (or 'main' - i.e. lowest impedance) path to earth were through someone's body, then the fault current would be tiny in comparison with what it would be with a 'proper earth', although undoubtedly still high enough to kill. A 'proper' TN earth will have an impedance of less than 1Ω, whereas the path through a human body is likely to be at least 1,000Ω.

Kind Regards, John

 

[conny]

You seem to be making the same mistake as Stuart, in assuming that the 'fault current' is a fixed entity whereas, in reality, it is totally dependent on the impedance of the path to earth.

If the only (or 'main' - i.e. lowest impedance) path to earth were through someone's body, then the fault current would be tiny in comparison with what it would be with a 'proper earth', although undoubtedly still high enough to kill. A 'proper' TN earth will have an impedance of less than 1Ω, whereas the path through a human body is likely to be at least 1,000Ω.

Kind Regards, John

But much lower if someone had got out of a shower and touched a radiator that was one of the paths, (or one foot in the water of a pressed steel bath).
The point I am trying to get across to the OP is to stop 'playing' around with this and get it sorted properly to avoid any potential incidents.