Earth-Leakage Protection (ANSI 50G-TD)

Presentation

Earth-leakage protection is a protection against earth fault with a very high sensitivity. It is generally used in TT or IT earthing systems but could also be used in TN earthing systems in some circumstances. Earth-leakage protection is a residual current protection based on current measured by a rectangular sensor encompassing the three phases or the three phases and neutral. MicroLogic 7.0 X earth-leakage protection including VPS module complies with IEC 60947-2 Annex B. It is a type A residual-current device (RCD).

Availability

WARNING
HAZARD OF EARTH-LEAKAGE PROTECTION LOSS Do not use MasterPacT MTZ with embedded MicroLogic 7.0 X control unit without connected rectangular sensor for earth-leakage protection. Only ever use Schneider Electric LV833573SP or LV833574SP earth-leakage protection sensors with MasterPacT MTZ with embedded MicroLogic 7.0 X control unit. Failure to follow these instructions can result in death, serious injury, or equipment damage.

WARNING

HAZARD OF EARTH-LEAKAGE PROTECTION LOSS

Do not use MasterPacT MTZ with embedded MicroLogic 7.0 X control unit without connected rectangular sensor for earth-leakage protection.
Only ever use Schneider Electric LV833573SP or LV833574SP earth-leakage protection sensors with MasterPacT MTZ with embedded MicroLogic 7.0 X control unit.

Failure to follow these instructions can result in death, serious injury, or equipment damage.

Earth-leakage protection is available on:

MicroLogic 7.0 X control units for IEC standard connected to an external rectangular sensor
3-pole and 4-pole circuit breakers

The external rectangular sensor is required to measure the residual current.

For information about installation of the rectangular sensor, consult the instruction sheet on the Schneider Electric website: NVE35468

The VPS voltage power supply module is delivered with MicroLogic 7.0 X control units to supply power to the control unit in case of a low-level electrical fault and no load, where the power supply based on current flowing through the circuit breaker is not high enough.

The VPS is mandatory to comply with IEC 60947-2 Annex B.

Operating Principle

Earth-leakage protection is definite time.

The earth-leakage protection threshold IΔn sets the level of earth-leakage at which the circuit breaker trips when reaching the earth-leakage protection time delay Δt.

Setting the Protection

The earth-leakage protection settings are:

IΔn: earth-leakage protection threshold
Δt: earth-leakage protection time delay

They can be set as follows:

On the MicroLogic X display screen, at Home > Protection > I Earth Leakage
With EcoStruxure Power Commission software (password-protected)
With EcoStruxure Power Device app (password-protected)
By sending a setting command using the communication network (password-protected).

Protection Settings

Setting	Unit	Range	Step	Factory setting	Accuracy
IΔn	A	0.5–30	0.1	0.5	Complies with IEC 60947-2 Annex B

Setting	Unit	Setting Value
Δt	s	0.06	0.15	0.23	0.35	0.80
Non-tripping time	s	> 0.06	> 0.15	> 0.23	> 0.35	> 0.80
Maximum breaking time	s	< 0.14	< 0.23	< 0.35	< 0.80	< 1.00

Testing the Protection

Test the operation of earth-leakage protection as follows:

Step	Action
1	Check that the circuit breaker is closed and the control unit is supplied with power (ready LED is flashing).
2	Use a thin screwdriver to briefly push in (< 1 s) the test button (T) on the front face of the MicroLogic X control unit. This action is recorded as an event.
3	The circuit breaker trips. An event is generated.
4	If the circuit breaker does not trip, an event is generated. Contact your Schneider Electric Services representative.

Predefined Events

The function generates the following predefined events:

Code	Event	History	Severity
0x6404 (25604)	IΔn trip	Trip	High
0x641E (25630)	IΔn/Ig test trip	Trip	High
0x6204 (25092)	IΔn start	Protection	Low
0x6304 (25348)	IΔn operate	Protection	Medium
0x142A (5162)	IΔn/Ig test button pressed	Diagnostic	Low
0x1413 (5139)	IΔn/Ig test - no trip	Diagnostic	High

Predefined events cannot be modified by the user. For general information about events, refer to Event management.

Protection events are generated as follows:

The start event is generated when the protection picks up.
The operate event is generated when the protection time delay elapses.
The trip event is generated when the circuit breaker tripping voltage release (MITOP) activates.

Recommended Actions

Code	Event	Recommended actions
0x6404 (25604)	IΔn trip	Reset the device or use the Power restoration assistant within the EcoStruxure Power Device app.
0x641E (25630)	IΔn/Ig test trip	Reset the device or use the Power restoration assistant within the EcoStruxure Power Device app.
0x1413 (5139)	IΔn/Ig test - no trip	Restart the test. If it fails again, replace the control unit.

Resetting a Trip Event

For information about resetting the circuit breaker after a trip due to an electrical fault, refer to the relevant document:

MasterPacT MTZ1 - Circuit Breakers and Switch-Disconnectors - User Guide
MasterPacT MTZ2/MTZ3 - Circuit Breakers and Switch-Disconnectors - User Guide