nulling test leads

[r.b]

Ive got an exam coming up I know before every test I should null the leads to get the correct reading.But what happens when you have got say 4 sockets close together obviously using a plug in tester so you dont take the socket fronts off.Do you have to keep nullin the meter for each of the socket tests or can you just null the meter once before and test the sockets in a row one after other Id like to know which way is correct because one saves time Ryan

 

[Zeespark]

Null once and save it on the tester, no further nulling of the leads is required after that, but you do have to null each time you turn your tester on again to use it.

AndyGuinness

 

[NozSpark]

Personally I'd just null them when you select that particular function, you could check they're still nulled once you're finished testing!

 

[Sidewinder]

Null on turn on or change of function, i.e. from low R to Z etc.

 

[steptoe]

^+ to the above, null on power up or change of function/test

 

[Evans Electric]

I null the leads on my Continuity/ insulation tester then if you leave it switched on it starts wailing , so switch off and its no longer nulled.

I must admit to recording out quite a few tests which include the leads . Two short leads seem to have a higher resistance than 50m of 1.00 .

Answer to question is I think the nulling lasts until you switch off , but you need to check.

 

[Voltimax]

What testers are you guys using?

I only have to null my MFT 1552 once or if I change the lead attachments. If the tester turns itself off, or I do, when switched on again the leads are still nulled and are indicated as such.

 

[Sidewinder]

I thought this then I did some experiments and with my old meter they needed to be done on change of setting & when powering up, I have not checked with my new meter yet.

However it appears that I had a dud set of leads on my old meter.

 

[Manator]

I have a length of wire in my tester box which is a known resistance, even nulled I double check by habbit more than anything. I still do not trust auto null features. 9 times out of 10 I still use the deduction method. I have faith in the recordings then. Old habbits die hard I suppose.

 

[batty]

The resistance of the leads should not change so once they have been nulled that should be it and meter should not change well my Fluke 1652 does not anyway. As said in a previous thread I tend to use a socket adaptor when testing sockets that way they don't need nulling each time you change between tests. I tend to use unfused crocs and probs on insulation and resistance testing because I find the fused ones always give different results even if you null them I currently use kewtech leads in my fluke because the fluke ones failed.

 

[a1]

I have a habbit of crossing the leads, pressing zero, and then pressing "Test" to make sure they have nulled and show a reading of 0.00ohms.

 

[Litttle Shonet]

It might be a good idea to check for null reading half way through each test, for good practice. But I don't, I only check them again if I have an unusal reading.