Earthing Disconnection Alert

[ejazbeyond]

i want to make a device which can send a alert via sms/gprs as somebody disconnect earthing wire.
my first approcah is to use a voltage sensor between phase and earth and send alert using arduino and sim800, but its costly.

 

[Nigel Goodwin]

i want to make a device which can send a alert via sms/gprs as somebody disconnect earthing wire.
my first approcah is to use a voltage sensor between phase and earth and send alert using arduino and sim800, but its costly.

Don't use an Arduino then, use a bare processor and a SIM800, it doesn't get much cheaper than that - but even using an Arduino it's not 'costly'.

 

[ejazbeyond]

Don't use an Arduino then, use a bare processor and a SIM800, it doesn't get much cheaper than that - but even using an Arduino it's not 'costly'.

is there any other method rather than using a voltage sensor because we don't need to measure the voltage just checking connectivity.

 

[Nigel Goodwin]

is there any other method rather than using a voltage sensor because we don't need to measure the voltage just checking connectivity.

I don't know as a voltage sensor would work anyway - but as always in these cases your question is extremely vague, EXACTLY what are you trying to do?, what on?, and why?.

 

[ejazbeyond]

my requirement is just to send an alert whenever someone disconnects an earthing wire from a panel/device.

 

[Nigel Goodwin]

my requirement is just to send an alert whenever someone disconnects an earthing wire from a panel/device.

Again, it's very vague - I suspect you're probably not going to find a universal solution.

Why would you even want to though?, do you have a problem with people deliberately going round disconnecting earth leads?, and why separate earth leads anyway?.

 

[Pommie]

If your earth connection is disconnected then the neutral is still earthed via next door and in many other places. What do you expect to see on your voltage measurement when it's disconnected? Plus, a phase imbalance could just as easily change the voltage of one phase to earth.

Mike.

 

[ejazbeyond]

If your earth connection is disconnected then the neutral is still earthed via next door and in many other places. What do you expect to see on your voltage measurement when it's disconnected? Plus, a phase imbalance could just as easily change the voltage of one phase to earth.

Mike.

when there is no earth voltage between earth and phase will be zero. which i want to send as alert over GSM

 

[Pommie]

when there is no earth voltage between earth and phase will be zero. which i want to send as alert over GSM

What makes you think it will be zero? The neutral will still be earthed via your neighbors, at the sub station and many other places. Note that even when the neutral is earthed it will still "wander" around between (in the triangle) the phases depending on the load on each phase.

Mike.

 

[ejazbeyond]

What makes you think it will be zero? The neutral will still be earthed via your neighbors, at the sub station and many other places. Note that even when the neutral is earthed it will still "wander" around between (in the triangle) the phases depending on the load on each phase.

Mike.

if earth wire is disconnected then there will be no voltage between earth and phase, if the circuit is not completed it's obvious there will be no voltage. i just checked it with a multimeter i am getting less than 20v between phase and earth when earth is disconnected, and when there is earth available its 230v

 

[Pommie]

I don't know what you are measuring but when I worked on high voltage switchgear the systems relied on an earth connection for fault detection, so even if your local earth is disconnected there will be enough of a path to earth to still detect faults. The connection may be via the armour of the supply cable or simply the neutral being earthed by multiple neighbors. Actually, what are you referring to as an "Earthing cable", I'm assuming the one that connects the neutral to earth via a ground spike, you?

Mike.