1
2365 LEVEL 2 ELECTRICAL INSTALLATION
(DETAILED UP TO DATE 2025)
Who is responsible in The consumer and or the electrical contractor
the Uk for making sure
an installation is
adequately earthed
Star point of transformer On the secondary side , neutral and tied
down to earth which is accepted at being
Zero Volts
Earth Fault Loop Path As low a value of impedance as possible
Earth Fault Impedance ZS
known as
External Loop Ze
Impedance
Zs Formula Zs = ZE + R1 + R2
I=V
Earth Fault Current ---
Zs
TT
TNS
The 5 Earthing Systems TN-
C-S
IT
TNC
TT Tera Tera - electricity supply company does
not provide any earth , live neutral only
, 2
TT System Earth Rod or
Method of Earth and Electrode Earth
Max ZE Plate or Mesh
Max ZE = 21
ohms
Tera Neutral Separate
TNS Separate Earth and Neutral From Supplier -
Separate on Installation Side
Supplier neutral earth link as near as
practicable to the source supply
TNS Earthing Method
transformer
Consumer Earth Connected to Metal Sheath
Of Supply Cable Max Ze = 0.8 ohms
2365 LEVEL 2 ELECTRICAL INSTALLATION
(DETAILED UP TO DATE 2025)
Who is responsible in The consumer and or the electrical contractor
the Uk for making sure
an installation is
adequately earthed
Star point of transformer On the secondary side , neutral and tied
down to earth which is accepted at being
Zero Volts
Earth Fault Loop Path As low a value of impedance as possible
Earth Fault Impedance ZS
known as
External Loop Ze
Impedance
Zs Formula Zs = ZE + R1 + R2
I=V
Earth Fault Current ---
Zs
TT
TNS
The 5 Earthing Systems TN-
C-S
IT
TNC
TT Tera Tera - electricity supply company does
not provide any earth , live neutral only
, 2
TT System Earth Rod or
Method of Earth and Electrode Earth
Max ZE Plate or Mesh
Max ZE = 21
ohms
Tera Neutral Separate
TNS Separate Earth and Neutral From Supplier -
Separate on Installation Side
Supplier neutral earth link as near as
practicable to the source supply
TNS Earthing Method
transformer
Consumer Earth Connected to Metal Sheath
Of Supply Cable Max Ze = 0.8 ohms
