Testing Zs. got a bang

[studentspark]

Using the Megger 1553 to test a RCD protected cooker switch point/s Zs

Being RCD protected I went for the three lead method, upon making the live connection I got a flash, which scorched the probe a bit.

I tested on the feed side.

Why would that happen

 

[Lectrician]

Shorted your probe to the earth bar adajcent.....

 

[Spark123]

Did you have the plastic end caps on the probes so only the spikes at the end were showing?

 

[studentspark]

Tips long gone

Use clip for earth. Took good care as live test, good connection to earth not springing off. good access to the terminals, firm on to neutral and live or so i thought.
popped when live connection made. Really don't think probes touched.

 

[Spark123]

As Lec said, if you haven't got the plastic shrouds on there is a possibility of the red probe coming into contact with the earth bar in the accessory and shorting it to the live terminal when you make contact with it.

 

[bhm1712]

if you got a bang, then id say you definitely shorted to earth no doubt.

you need to be extremely careful if testing live no matter how safe you think you are.

 

[flameport]

upon making the live connection I got a flash, which scorched the probe a bit.

Depends on what you mean by 'flash'.

If the probe wasn't firmly pressed against the terminal, it is possible to get a small spark, in the same way that a switch will spark when turning on/off under load.

If there was a big bang and flash, live was shorted to earth or neutral.

 

[ban-all-sheds]

Let's see a close-up photo of the offending probe...

 

[ricicle]

Agreed - if the probe is not in proper contact when the test current flows there can be a significant flash/pop !

 

[studentspark]

View media item 20920 View media item 20921
here is the probe

 

[Guitarguy]

It has definately made contact to earth/neutral at the side somewhere.

 

[ColJack]

yeah, that's a short.. it's melted at the side where you contacted the earth or neutral..

you need new leads as you are breaking GS38 with those..

 

[ban-all-sheds]

Never mind - I don't suppose they are very expensive....

 

[333rocky333]

I would be more concerned with any damage to the cooker switch.

Did the RCD trip ?

 

[Adam_151]

I find the GS38 tips on my alphatek unworkable, you have to take them off to get in some terminals, then you end up leaving them off and then you come across an accessory that has the earth link bar a little close and you go and test it without thinking and BANG!... complete nuisense to have to break off what you are doing to fetch your fusewire

Got just the right amount of tape around them now instead of the tips...probably falls fowl of something or other, but is actually workable!