V.O.E.L.C.B.

broadgage:

Sparkingchip:

What is the tripping current of a Voltage Operated Earth Leakage Circuit Breaker?

They do not have a tripping current.

They trip when the VOLTAGE between true earth (earth rod) and the earth wires of the installation reaches a certain figure, often 50 volts.

So if a defective class one appliance raises the voltage of the green wires in the house to more than 50 volts, it should trip.

If working correctly they give reasonable protection to persons within a home, against any defect in the wiring or appliances of that home.

In the case of equipment used outdoors they give very limited protection.

If the electric drill had a short circuit between phase and earth, that should raise the system earth voltage to more than 50 volts, and promptly trip the supply.

If however the flex of the appliance was damaged, and the user touched the phase wire, they would get a serious and perhaps fatal shock. There is no way that a VOELCB will "know" the difference between an amp passing through a human to earth, and another amp of load current.

The other risk is if pre-existing earth leakage had raised the system earth voltage to 49 volts, A class one appliance used outdoors would give the user a 49 volt shock. Much less dangerous than line voltage, but still twice the limit of SELV.

I am substantially in agreement with broadgage who is much more knowledgeable than me in most cases. I have read from manufacturers' literature that the V.O.E.L.C.B.s operated at well below the claimed 50 Volts max. to Earth. Typically 30 to 40 Volts is quoted. But of course they do not comply with the wiring regulations any more.

broadgage:

Sparkingchip:

What is the tripping current of a Voltage Operated Earth Leakage Circuit Breaker?

They do not have a tripping current.

They trip when the VOLTAGE between true earth (earth rod) and the earth wires of the installation reaches a certain figure, often 50 volts.

So if a defective class one appliance raises the voltage of the green wires in the house to more than 50 volts, it should trip.

If working correctly they give reasonable protection to persons within a home, against any defect in the wiring or appliances of that home.

In the case of equipment used outdoors they give very limited protection.

If the electric drill had a short circuit between phase and earth, that should raise the system earth voltage to more than 50 volts, and promptly trip the supply.

If however the flex of the appliance was damaged, and the user touched the phase wire, they would get a serious and perhaps fatal shock. There is no way that a VOELCB will "know" the difference between an amp passing through a human to earth, and another amp of load current.

The other risk is if pre-existing earth leakage had raised the system earth voltage to 49 volts, A class one appliance used outdoors would give the user a 49 volt shock. Much less dangerous than line voltage, but still twice the limit of SELV.

I am substantially in agreement with broadgage who is much more knowledgeable than me in most cases. I have read from manufacturers' literature that the V.O.E.L.C.B.s operated at well below the claimed 50 Volts max. to Earth. Typically 30 to 40 Volts is quoted. But of course they do not comply with the wiring regulations any more.