Megga MST 1552 Help

[beemer]

I have a colleague who has recently passed his C&G2391 (we were on the same 2330 course for 3 years) and has a job with an electrical company in the testing section. He has been given a Megga MFT 1552 tester and seems to be having problems with his Pfc readings.

The situation is he gets a pfc of around 4KA at origin but his companies parameters are 1.9KA max. He thinks he might be doing the test wrong.

His instructions indicate that he needs only use two leads when testing L-N for psc and L-E for pfc.

Is this correct? I don't know the Megga (I have a Meterel) so can not help him.

Thanks in advance..

Dave

 

[steptoe]

its exactly the same test,

just on different cable.

dunno what 2 leads a megger uses, but lets say its the Ph + E, then you do the test across phase + earth, then put your earth lead on the neutral cable and repeat the test, use the highest reading.

remember on 3phase to use the correction factor,

PFC and PSCC IMHO are the same thing,.

or tell him if he gives me

 

[norv]

I always use the 2 leads on my 1552 & put the setting on PFC HI.

 

[kme]

I have a colleague who has recently passed his C&G2391 (we were on the same 2330 course for 3 years) and has a job with an electrical company in the testing section. He has been given a Megga MFT 1552 tester and seems to be having problems with his Pfc readings.The situation is he gets a pfc of around 4KA at origin but

his companies parameters are 1.9KA max.

He thinks he might be doing the test wrong

His instructions indicate that he needs only use two leads when testing L-N for psc and L-E for pfc.

[/uNQUOTE]

Is this correct? I don't know the Megga (I have a Meterel) so can not help him.

Thanks in advance..

Dave

A Ze of 0.12 at Uo 230v will provide approx 1.9KA. 0.05 will give 4KA. On TN systems (esp. PME), readings as low as 0.01 are not uncommon (i.e. 10KA+)

The third lead allows for non-tripping RCDs on Zi testing (though apparently the new meggers can do this with 2 leads??)

HTH

 

[state-it]

its exactly the same test,PFC and PSCC IMHO are the same thing,.

...on a TN-C-S system

 

[steptoe]

...on a TN-C-S system

so whats the difference?

on any system,

between the fault current and the short circuit current(which is simply a FAULT)

its always the highest reading that is used

?:| ? :|

 

[SPECIAL LOCATION]

so whats the difference?on any system,

between the fault current and the short circuit current(which is simply a FAULT)

its always the highest reading that is used

?:| ? :|

To my understanding..

PFC: is the fault current between phase & earth.

live - earth fault!

PSCC: is the fault current between phase & neutral

live - neutral fault!

They can be different!

and as you say Highest value is used!

 

[Apprenticespark]

I always thought PFC was the higher reading from PEFC and PSCC . Oh well.

 

[steptoe]

the actual readings may be different,

but as I understand it that is why it was changed from simply PSCC to a PFC reading.

a FAULT is a FAULT, doesnt matter if its a between phase neutral, or between phase earth.

its all about the prospective highest current that will flow in the circumstances.

 

[SPECIAL LOCATION]

the actual readings may be different,but as I understand it that is why it was changed from simply PSCC to a PFC reading.

a FAULT is a FAULT, doesnt matter if its a between phase neutral, or between phase earth.

its all about the prospective highest current that will flow in the circumstances.

Yes M8.

I think the point being if using some three lead testers..

you need to stick your leads across red (L)- black(N)- Green(E)

or brown/blue etc.. to read live earth fault.

then stick green onto (N) to read live neutral fault.

then stick down the biggest value on your cert.

 

[kme]

I fink that wot I said m8:

The third lead allows for non-tripping RCDs on Zi testing (though apparently the new meggers can do this with 2 leads??)

HTH

I don`t have the megger literature to hand to check. Fluke`s better anyway!!! ] ]

:^O :^O:^O

 

[steptoe]

I fink that wot I said m8:I don`t have the megger literature to hand to check. Fluke`s better anyway!!! ] ]

:^O :^O:^O

you taking the p iss kme??? ]