Some MFTs have PSC/PFC test combined, I wonder why others have it as a separate test

[pc1966]

In "no trip" mode my DL9118 does high current L-N and low current L-E on the one test, afterwards you can press the top 'function' key and it toggles between the Zs/PFC and the Zsupply/PSCC results.

In high current mode it only measures the one you select, which is odd.

My suspicion is it makes some use of the PSCC data to help with the no-trip test, but there is nothing said about any of that in the instruction book, etc. For example, with the 3 wire connection while you measure the L-N drop you could also measure the N-E rise to get some idea of R1 and Rn separately (at least as far back as the N-E link point in the distribution system), and it might help when you do the L-E test to get some idea of R2 by knowing R1 from the first test, etc. But that is speculation!

 

[HappyHippyDad]

All loop testers can do a L-N loop test, you connect one lead to L and the other to N and press the test button.

Could you explain in clearer, more simple terms please Dave.

 

[westward10]

Could you explain in clearer, more simple terms please Dave.

Do you use three leads or two leads?

 

[HappyHippyDad]

Do you use three leads or two leads?

Right, I was joking, as Dave had explained it extremely clearly.
Now I feel silly as I 'think' you've taken it seriously.

 

[timhoward]

I can't explain it, I have to do a double take and make sure it wasn't just a one off, and it wasn't. I got different results and I have absolutely no idea why.

What scale of difference do you see?
For me the readings are generally slightly higher on the L-N setting, using the same lead and simply moving the plug. We are talking 0.05 ohm variation at most.
The readings on both settings are however slightly inconsistent in their own right; 10 tests in a row with suitable pause between each one also yields variation within a 0.05 ohm window.
The N socket on mine has had considerably less use and I also wondered if it might simply have more tarnished contacts!

 

[davesparks]

That's nice I was just wondering why is there an option L-PE or L-N if you can stay in L-PE mode to test L-N

Because adding lots of features and options allows manufacturers to charge more money.