Zeroing fluke 1653b tester help

[schoe]

Hi all not sure if I'm zeroing my test instrument correctly as I've got different test results when carrying out my pefc an psc.

What I've been doing when carrying out these tests is connecting all the 3 test leads together and holding zero however on the display it's stating 0.14 ohms instead of 0.00 for example when carrying out continuity tests.

Today when doing the tests I got these results

Pefc 1.5ka
Psc 1.6ka

I then carried out the tests later on and got these results

Pefc 1.6ka
Psc 2.5 ka

So as you can see I'm not sure if I'm zeroing my meter correctly, any help would be great,

Thanks chris

 

[ackbarthestar]

Fluke recommend that you short out the probes and press the start button before live testing.
However, more importantly, pfc/psc are live tests where the supply voltage is changing continually.
Think of it like this
By calculation psc = Uo/Ze (single phase) where Uo is taken as 230V
but this is not really true in real life, where Uo can change from 216 - 253v in minutes, depending on where you live or what type of installation you are testing.

 

[Guest123]

You only need to null the DB leads & the kettle lead once using the shorting adapter & the zero button when you first use it.

It does show you on the test diagram cards you get with the machine.

 

[HandySparks]

What I've been doing when carrying out these tests is connecting all the 3 test leads together and holding zero however on the display it's stating 0.14 ohms instead of 0.00 for example when carrying out continuity tests.

The 0.14 ohms reading is the resistance of the test leads (and sounds about right). If you then press the test button with the leads still shorted you should get a reading of 0.00.

 

[MarkieSparkie]

Hi Schoe,
Fluke 165xx series MFTs are a bit temperamental when it comes to lead nulling. The manufacturers standard method is by way of the Fluke zero adaptor (provided as part of all 165xB,C&D series kits).
Somewhere in your Fluke box there should be a fancy piece of bent metal which Fluke provide as a device to aid nulling the Fluke leads. They call this expensive accessory the "zero adapter", it is provided because unlike most MFTs the 165xx series also require the BS1363 loop/RCD test lead to nulled before its use and the zero adapter allows easy shorting of the BS1363 plug pins. The zero adapter also has 3x4mm sockets to allow nulling of the red, black and green leads when used as prods or with croc-clips. Before the introduction of this device Fluke were getting a lot of complaints about inconsistent continuity and loop/RCD test results, caused by poor nulling or lack of nulling of the test leads.
Fluke zero adaptor (165xx) Part No. 3261925, £31 + VAT @1/2/2011
A scrap piece of 30mm wide x 50mm long copper busbar with 3 x 4mm holes in one end for nulling the 3 lead set or shorting the pins of the BS1363 plug. Alternatively 300 mm length of 1mmsq CPC wrapped round the pins of the BS1363 plug of the loop/RCD test lead are reasonable substitutes. Another method used by one of my colleges is to short the BS1363 pins on a stainless steel drainer, but it's a bit bulky to carry with you.:rolleyes2:
The particularly important point is giving the croc-clips (if used) something to bite on and a method that doesn't require juggling all the leads at once.