Hello all,
I've got a question about Inspection and Testing, I'm a domestic Installer and have done a fair bit of testing and signing off my own work. This is my first time I've had anything to do with TT systems and need some advice.
I have been installing a circuit in a property which is TT, has a Main Switch which is an RCD (100mA) and the circuit I am installing is 32 Amp Type B 60898 MCB with a disconnection time of 0.4s. I'm happy with what I've done, the work is neat & tidy, its not a long circuit so if it was a TNS or TNCS i know the reading would be ok. I am using three leads with the Tester on No Trip, so getting a reading.
The Ze is 11 ohms (very good reading for an earth rod), the R1 + R2 is 0.4 ohms but when I do the Earth Fault Loop Impeadence Test the reading is 13.6 ohms
This is what you would expect if you do the maths, but when I look at the value permitted (1.16 ohms), it obviously fails.
I'm looking at page 103 of 17th Ed OSG.
Many thanks in advance for any replies
Gazza
I've got a question about Inspection and Testing, I'm a domestic Installer and have done a fair bit of testing and signing off my own work. This is my first time I've had anything to do with TT systems and need some advice.
I have been installing a circuit in a property which is TT, has a Main Switch which is an RCD (100mA) and the circuit I am installing is 32 Amp Type B 60898 MCB with a disconnection time of 0.4s. I'm happy with what I've done, the work is neat & tidy, its not a long circuit so if it was a TNS or TNCS i know the reading would be ok. I am using three leads with the Tester on No Trip, so getting a reading.
The Ze is 11 ohms (very good reading for an earth rod), the R1 + R2 is 0.4 ohms but when I do the Earth Fault Loop Impeadence Test the reading is 13.6 ohms
This is what you would expect if you do the maths, but when I look at the value permitted (1.16 ohms), it obviously fails.
I'm looking at page 103 of 17th Ed OSG.
Many thanks in advance for any replies
Gazza