OP
amberleaf
Idon’t . as a rule
Idon’t . as a rule download onto the main forum .
Lenny. I do ask for your Indulges .
Thismatter is intended for 2394:
Pointsto remember : 2394 : ( Ze & ( Zs )
Earth-Fault-Loop-Impedance Testing
When Measuring ( Ze )the means of ( Earthing )
Earthing-Conductor must be disconnected from the Installation for the duration of the test. To remove parallel-paths .
- External-Loop-Impedance- ( Ze )
Measuring ( Zs ) neither the means of Earthing or theBonding-conductors must be disconnected to Retainthe ( Parallel-Path ) Lower ReadingsΩ .
- Circuit-Loop-Impedance( Zs )
- - - Updated - - -
Ido request the Members indulges . Thankyou .
Calculationsfor earth fault loop impedance
Earth-Fault-Loop-Impedance.
The. Earth-fault-loop-impedance is given by .
(Zs = Ze + R[SUP]1[/SUP] + R[SUP]2[/SUP] )
Thevalue of ( Zs ) can be found by .
i). Measuring the . earth-fault-loop-impedance - ( Zs ) at the furthest-point .
ii). Measuring the . earth-fault-loop-impedance - ( Ze ) at the Origin of theInstallation ( at the Incoming-supply& adding ( R[SUP]1[/SUP] + R[SUP]2[/SUP] )
iii). Taking the . earth-fault-loop-impedance - ( Ze ) provided by the DNO . &adding - ( R[SUP]1[/SUP] + R[SUP]2[/SUP] )
Pointto Note : Obtaining the value of ( Zs )Measurement of ( Zs )
Readings obtained using this method will be ( Less-than ) Ze + (R[SUP]1[/SUP] + R[SUP]2[/SUP] ) because of .Parallel-Earth-Paths .
(Zs ) Plug-in - Instrument Loop-setting . will give you . Earth-Loop-Impedancevalue . 0.3Ω
Earth-Fault-Loop-Impedance. Test on a circuit - ( Zs )
Live-Test : ≈
Thereason for this Test . is to ensure the . Earth-Fault-Loop-Impedance ( Zs ) isLow enough to ensure that enough current can flow through the circuit to operate the protective-device in therequired-time .
Thissocket-outlet is protected by an RCD .
ToCarry out this Test . Instrument that will use a Low-current to carry out this Test .
Note - The Socket-Outletis Switch OFF .
Instrument: Megger - LTW325 : ( Loop) Set it to No-Trip . Plug in into theSocket-outlet . “ switch it On “ Your reading - 0.35Ω
Compareit directly to the O.S.G. - Table B6 - p.119
(32A ) type B . protective-device .
Useyour chart . go down Left-hand column (B ) along the Top ( 32A ) three-down .where the linesmeet these a value of ( 1.24Ω ) 1.24is higher than 0.35Ω
0.35Ω being lower . more current will flow throughthe system than required to operate the circuit-protective-device .
Idon’t . as a rule download onto the main forum .
Lenny. I do ask for your Indulges .
Thismatter is intended for 2394:
Pointsto remember : 2394 : ( Ze & ( Zs )
Earth-Fault-Loop-Impedance Testing
When Measuring ( Ze )the means of ( Earthing )
Earthing-Conductor must be disconnected from the Installation for the duration of the test. To remove parallel-paths .
- External-Loop-Impedance- ( Ze )
Measuring ( Zs ) neither the means of Earthing or theBonding-conductors must be disconnected to Retainthe ( Parallel-Path ) Lower ReadingsΩ .
- Circuit-Loop-Impedance( Zs )
- - - Updated - - -
Ido request the Members indulges . Thankyou .
Calculationsfor earth fault loop impedance
Earth-Fault-Loop-Impedance.
The. Earth-fault-loop-impedance is given by .
(Zs = Ze + R[SUP]1[/SUP] + R[SUP]2[/SUP] )
Thevalue of ( Zs ) can be found by .
i). Measuring the . earth-fault-loop-impedance - ( Zs ) at the furthest-point .
ii). Measuring the . earth-fault-loop-impedance - ( Ze ) at the Origin of theInstallation ( at the Incoming-supply& adding ( R[SUP]1[/SUP] + R[SUP]2[/SUP] )
iii). Taking the . earth-fault-loop-impedance - ( Ze ) provided by the DNO . &adding - ( R[SUP]1[/SUP] + R[SUP]2[/SUP] )
Pointto Note : Obtaining the value of ( Zs )Measurement of ( Zs )
Readings obtained using this method will be ( Less-than ) Ze + (R[SUP]1[/SUP] + R[SUP]2[/SUP] ) because of .Parallel-Earth-Paths .
(Zs ) Plug-in - Instrument Loop-setting . will give you . Earth-Loop-Impedancevalue . 0.3Ω
Earth-Fault-Loop-Impedance. Test on a circuit - ( Zs )
Live-Test : ≈
Thereason for this Test . is to ensure the . Earth-Fault-Loop-Impedance ( Zs ) isLow enough to ensure that enough current can flow through the circuit to operate the protective-device in therequired-time .
Thissocket-outlet is protected by an RCD .
ToCarry out this Test . Instrument that will use a Low-current to carry out this Test .
Note - The Socket-Outletis Switch OFF .
Instrument: Megger - LTW325 : ( Loop) Set it to No-Trip . Plug in into theSocket-outlet . “ switch it On “ Your reading - 0.35Ω
Compareit directly to the O.S.G. - Table B6 - p.119
(32A ) type B . protective-device .
Useyour chart . go down Left-hand column (B ) along the Top ( 32A ) three-down .where the linesmeet these a value of ( 1.24Ω ) 1.24is higher than 0.35Ω
0.35Ω being lower . more current will flow throughthe system than required to operate the circuit-protective-device .