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- 4 May 2007
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Hi Folks
I'm part way through my studies and we've just been learning about ELI.
I thought I was begining to understand it until I did a test on my own installation today.
The problem is, is that my ZE reading is HIGHER than ZS. If I'm right ZS=ZE + (R1 + R2). I'm on a TT system and got the following readings :
ZE = 55ohms
R1 + R2 = 0.6ohms
ZS (Measured) is 4.72ohms
If ZS = ZE =(R1 + R2) then surely ZS should be about 55.6ohms??? (Or is ZS simply the R1+R2 measurement?)
To Measure ZE I dissconnected the Main earth cable from the MET and measured between it and the incoming phase.
I also disconnected all MEB's when measuring ZS. I measuerd at all the sockets on the ring but the reading was pretty much the same.
I've got a megger MFT52 and switched it to NO Trip for the ZS test.
Could someone explain where I'm going wrong, please?
Cheers
I'm part way through my studies and we've just been learning about ELI.
I thought I was begining to understand it until I did a test on my own installation today.
The problem is, is that my ZE reading is HIGHER than ZS. If I'm right ZS=ZE + (R1 + R2). I'm on a TT system and got the following readings :
ZE = 55ohms
R1 + R2 = 0.6ohms
ZS (Measured) is 4.72ohms
If ZS = ZE =(R1 + R2) then surely ZS should be about 55.6ohms??? (Or is ZS simply the R1+R2 measurement?)
To Measure ZE I dissconnected the Main earth cable from the MET and measured between it and the incoming phase.
I also disconnected all MEB's when measuring ZS. I measuerd at all the sockets on the ring but the reading was pretty much the same.
I've got a megger MFT52 and switched it to NO Trip for the ZS test.
Could someone explain where I'm going wrong, please?
Cheers