Fluke testing on tt system - urgent assistance please

[sidekick]

I have a Fluke 1653 multi function tester and after testing on a TT system need help to ensure I am recording the correct readings from the display.

Readings are as follows :-

Main earth disconnected, Z1 (loop) selected, F1 L-PE selected and three leads connected. Green to main earth, blue to in neutral and red to in line. Test = upper display 0.40 ohms, lower display 619A. F1 L-N selected, Test = upper display 76.3 ohms, Lower display 3A.

Main earth connected, Z1 (loop) selected, F1 L-N selected, Test = upper display 26.6 ohms, lower display 9A.

Am I correct in recording Ze as 0.40 ohms, PFC as 619A and earth electrode resistance as 76.3 ohms

Are these readings acceptable and If not – where am I going wrong?

A quick reply with assistance would be appreciated as I cannot put the installation live until 100% and need to certify asap.

Thanks

 

[philip962]

Re: Ze, EARTH ROD RESISTANCE AND PFC TEST ON TT SYSTEM

http://www.electriciansforums.net/i...formation-electrical-form-filling-bs7671.html try this link mate hope it helps

 

[pevvers]

Ah, the joys of using a three lead instrument with too many function buttons... Give me a nice Megger two lead set, then you know for sure which loop you're reading as it will be whichever one your probes are on!

In reply though, loop reading for a TT will be higher than 0.40, so could be the 70 or 20 odd reading you have. But it seems strange that you got the low reading on what appears to be the correct setting. Not having used Fluke MFTs too much then that's all I can say, but there are many Fluke users on here that will be able to help you,

 

[Deleted member 9648]

Re: Ze, EARTH ROD RESISTANCE AND PFC TEST ON TT SYSTEM

I have a Fluke 1653 multi function tester and after testing on a TT system need help to ensure I am recording the correct readings from the display.

Readings are as follows :-

Main earth disconnected, Z1 (loop) selected, F1 L-PE selected and three leads connected. Green to main earth, blue to in neutral and red to in line. Test = upper display 0.40 ohms, lower display 619A. F1 L-N selected, Test = upper display 76.3 ohms, Lower display 3A.
I'm not familiar with the tester but your results appear the wrong way round...if the main earth is going straight to the electrode on the first test I would expect the second set of readings and for the L-N test (second test ) the first set of readings.
So the Ze and ELR would be 76.3 and the PFC 619a.

Main earth connected, Z1 (loop) selected, F1 L-N selected, Test = upper display 26.6 ohms, lower display 9A.

Am I correct in recording Ze as 0.40 ohms, PFC as 619A and earth electrode resistance as 76.3 ohms

Are these readings acceptable and If not – where am I going wrong?

A quick reply with assistance would be appreciated as I cannot put the installation live until 100% and need to certify asap.

Thanks

hope this helps

 

[swparksey]

Not used a fluke for a while but that seems correct to me,

Did the display show RE if not press F3 i think during the first test.

 

[johnstantine]

I don't know much about the fluke testers, but I'm pretty confident you won't have anything like as low as .40 on a TT. Using a loop tester to measure earth electrode resistance, your Ze and electrode resistance will be more or less the same and will probably be the higher 76 ohm reading.
76 is normally acceptable for electrode resistance and Ze but you should prove this yourself by referring to the regs.

 

[sidekick]

Not used a fluke for a while but that seems correct to me,

Did the display show RE if not press F3 i think during the first test.

Did't press F3 so still showed Ik, however, retested a couple of times and pressed F3 to show RE and still got readings of 76.9 to 77.1

Thanks

 

[sidekick]

I don't know much about the fluke testers, but I'm pretty confident you won't have anything like as low as .40 on a TT. Using a loop tester to measure earth electrode resistance, your Ze and electrode resistance will be more or less the same and will probably be the higher 76 ohm reading.
76 is normally acceptable for electrode resistance and Ze but you should prove this yourself by referring to the regs.

Just to refer back to your comments. I retested and got between 76 and 77 ohms for RE on earth electrode but stil got between 35 and 40 for Ze ??