IR Readings

[WolvesJon]

Hi All

Ive just in the process of doing a rewire and have been doing some circuit testing with my new megger 1710. On some circuits im getting IR readings of between 300 to 600 Mohm others and showing >999.
My questions are:
1. should I be getting >999 on all circuits as it's a new rewire or are reading of between 300 & 600 Mohm perfectly acceptable.
2. if they are not acceptable, what could be causing them
I know these readings are all way above acceptable levels, and would never have even shown up on my 1552, but i am just after a bit of clarification. The property has just been completely replastered, could the damp in the plaster be affecting the readings?

Many Thanks
Jon

 

[KAS1]

I think you may just need a little more confidence and experience seems you've answered your own questions

 

[LittleHelper]

Hi All

Ive just in the process of doing a rewire and have been doing some circuit testing with my new megger 1710. On some circuits im getting IR readings of between 300 to 600 Mohm others and showing >999.
My questions are:
1. should I be getting >999 on all circuits as it's a new rewire or are reading of between 300 & 600 Mohm perfectly acceptable.
2. if they are not acceptable, what could be causing them
I know these readings are all way above acceptable levels, and would never have even shown up on my 1552, but i am just after a bit of clarification. The property has just been completely replastered, could the damp in the plaster be affecting the readings?

Many Thanks
Jon

If you have fcu's with neon lights can affect readings and things like transformers for downlighters, energy saving bulbs. could be just enviromental factors!

 

[telectrix]

agreed. just breathing on the leads could give that kind on a reading. bloody stupid these MFTs ranging to 999Meg. years ago >10Meg. was the norm. worry not.

 

[stuartcourt]

agree 200 ample on a new install prob is damp

 

[44ALLAN]

The property has just been completely replastered, could the damp in the plaster be affecting the readings?

In a nutshell...........yes.
So if you think that's what it is then go and disconnect and test again.
If it's still flat tails get the hair dryer out

 

[somersetsparks]

those are very good readings, no worries at all, if it is damp they usually climb slowly, The longer circuits will take a long time to 'charge' up to 1000 meg anyways, as has been said a tester need only read 200 anyway,
1 billion ohms is ridiculous!

 

[Octopus]

On the auto test my Metrel goes up to 30M so I wouldn't even know if there were differences. Only when I use it on individual tests does the range go up to 1000M!

 

[trev]

My questions are:
1. should I be getting >999 on all circuits as it's a new rewire or are reading of between 300 & 600 Mohm perfectly acceptable.

I know these readings are all way above acceptable levels,

[/QUOTE]
Obviously I've cut things out but Jon, have a word with yourself mate. Key things are knowledge, skill and confidence.

 

[Engineer54]

agreed. just breathing on the leads could give that kind on a reading. bloody stupid these MFTs ranging to 999Meg. years ago >10Meg. was the norm. worry not.

Don't you mean 100 Meg?? Can't think of any of the older analogue units i've used in the past, that were that low at the end of the range scale!!

 

[telectrix]

missed a zero out, eng. blame the age.

 

[Engineer54]

I always DO, ...for myself!! lol!!