Sequence of tests in guidance note 3 (initial verification)

[mak]

How come the sequence of tests in guidance note 3 is that the Zs test comes before the PFC test?

Isn't it normal to do PFC test before the Zs test? Because then you can do your PFC test, put the board cover on and energize the board without coming back to do the PFC test.

 

[Markyd]

So how would you do your ZS test at board...Think about it...Disconnect Main Earth do ZE test Reconnect Main Earth Do ZS.....How can you do a ZS at DB if cover is on

 

[mak]

So how would you do your ZS test at board...Think about it...Disconnect Main Earth do ZE test Reconnect Main Earth Do ZS.....How can you do a ZS at DB if cover is on

I would measure Zs on sockets using a plug adaptor and calculate the rest?

 

[pc1966]

Do you mean Ze, the impedance at the board, before you do the Zs, impedance at end of circuit?

In practically all cases you measure Zs/Ze along with the related PFC using your MFT.

 

[davesparks]

How come the sequence of tests in guidance note 3 is that the Zs test comes before the PFC test?

Isn't it normal to do PFC test before the Zs test? Because then you can do your PFC test, put the board cover on and energize the board without coming back to do the PFC test.

Can you post a picture of the list of tests you are referring to, there may be a detail you have missed.

Which Zs test is it referring to? The Zs at the DB or the Zs of final circuits?

PFC is calculated and displayed by the test meter for every loop impedance test, it's not possible to carry them out as seperate tests.

 

[telectrix]

PFC is calculated and displayed by the test meter for every loop impedance test, it's not possible to carry them out as seperate tests.

not on all meters. on the megger 1552/3 they are separate tests. don't know about the 1700 series.I can't afford anything that fancy.

 

[davesparks]

not on all meters. on the megger 1552/3 they are separate tests. don't know about the 1700 series.I can't afford anything that fancy.

Really? That seems a bit backwards considering that the meter doesn't measure the PFC, it measures the loop impedance and voltage and calculates PFC from that.

I've got a 1700 series and that displays PFC on the same screen, on my seperate high resoloution loop tester you press a button to cycle the display to show PFC.
I think the fluke and Kewtech I used in years gone by were the same, press a button to cycle the display and show PFC.

I just assumed they were all the same.

 

[Ian1981]

The kewtech kt64 has separate settings for measuring Zs and pfc

 

[telectrix]

Megger Mft 1553 Multifunction Tester With 12 Months Calibration Certificate | eBay

Find many great new & used options and get the best deals for Megger Mft 1553 Multifunction Tester With 12 Months Calibration Certificate at the best online prices at eBay! Free delivery for many products!

www.ebay.co.uk

if you zoom the pic, it shows separate tests for pfc. both on hi current and no-trip.

also posted link as this looks matbe a good buy for any trainee on a limited budget.

 

[Mark Wright]

if you followed the correct Sequence of tests you just do You Earth Fault Loop Impedance Ze at the board and add your result to your R1+R2 then do your PFC tests.