Multi Function Tester with low battery giving very low insulation resistance reading.

[Selfmade]

I have a Metrel MI3000 MFT. It has given very low insulation resistance readings for a circuit I was testing earlier today (0.001MΩ) between live and earth(!) but the circuit has been working fine and not tripping the MCB (20A, no RCD as it is a pre-17th ed. CU) and I had tested it only a couple of weeks before with the same MFT and got 81MΩ between live and earth. There has been no work done on the property since that test that could have damaged the circuit (owner says he hasn't so much as put up a picture hook). The battery in my MFT was getting quite low and I have previously noticed inconsistent results with a low battery. Has anyone else had any similar experiences or have any idea if I might be thinking along the right lines in thinking the low battery might be giving misleading results. I have arranged to go back and re-test tomorrow, with a charged battery!

 

[IQ Electrical]

Re: Multi Function Tester with low battery giving very low insulation resistance read

I have a Metrel MI3000 MFT. It has given very low insulation resistance readings for a circuit I was testing earlier today (0.001MΩ) between live and earth(!) but the circuit has been working fine and not tripping the MCB (20A, no RCD as it is a pre-17th ed. CU) and I had tested it only a couple of weeks before with the same MFT and got 81MΩ between live and earth. There has been no work done on the property since that test that could have damaged the circuit (owner says he hasn't so much as put up a picture hook). The battery in my MFT was getting quite low and I have previously noticed inconsistent results with a low battery. Has anyone else had any similar experiences or have any idea if I might be thinking along the right lines in thinking the low battery might be giving misleading results. I have arranged to go back and re-test tomorrow, with a charged battery!

You've probably answered your own question!

 

[kingeri]

Re: Multi Function Tester with low battery giving very low insulation resistance read

^^^^^ As above ^^^^^

Change the battery/ies.............

 

[stuartcourt]

Re: Multi Function Tester with low battery giving very low insulation resistance read

I had Metrel tester and as above low bat inconsistent readings

 

[trev]

Re: Multi Function Tester with low battery giving very low insulation resistance read

I once stabbed myself in the thigh to see if I would bleed, after attending A & E and getting put right I tried the same thing again and got exactly the same result which surprised me. Any ideas or advice guys. I might post that up on a medical forum, wonder what the response would be

 

[IQ Electrical]

Re: Multi Function Tester with low battery giving very low insulation resistance read

I once stabbed myself in the thigh to see if I would bleed, after attending A & E and getting put right I tried the same thing again and got exactly the same result which surprised me. Any ideas or advice guys. I might post that up on a medical forum, wonder what the response would be

It's like Deja Vu Trev!

 

[tony mc]

Re: Multi Function Tester with low battery giving very low insulation resistance read

Just out of interest does the Metrel give readings that low on IR testing ??

 

[Selfmade]

Re: Multi Function Tester with low battery giving very low insulation resistance read

Thanks all - very re-assuring!

 

[Selfmade]

Re: Multi Function Tester with low battery giving very low insulation resistance read

I once stabbed myself in the thigh to see if I would bleed, after attending A & E and getting put right I tried the same thing again and got exactly the same result which surprised me. Any ideas or advice guys. I might post that up on a medical forum, wonder what the response would be

Lol! When it happened previously it was not quite so extreme, and the MFT came with NiMH AA batteries, which as you will know have memory effect so I didn't want to keep topping them up and so reduce their capacity. Point taken though. Looks like I'll have to keep them topped up from now on!

 

[trev]

Re: Multi Function Tester with low battery giving very low insulation resistance read

Glad you saw the intended funny side mate, a lot don't and take a big girly huff.

 

[moospark]

Re: Multi Function Tester with low battery giving very low insulation resistance read

Thanks all - very re-assuring!

Had similar problem with my first torch mate, threw five of the buggers away before I sussed it
too slow

 

[Selfmade]

Re: Multi Function Tester with low battery giving very low insulation resistance read

Just out of interest does the Metrel give readings that low on IR testing ??

Yes, at least mine does, don't know about the other models. Mine will display anything from 0.000MΩ to >1000MΩ. I was quite surprised when I bought it having been trained on Meggers which only show three digits instead of four.

 

[Selfmade]

Re: Multi Function Tester with low battery giving very low insulation resistance read

Glad you saw the intended funny side mate, a lot don't and take a big girly huff.

Always good to lighten up an at-times stressful job! Take no notice of the huffs!

 

[Selfmade]

Re: Multi Function Tester with low battery giving very low insulation resistance read

Had similar problem with my first torch mate, threw five of the buggers away before I sussed it

A re-assuring torch? And that's a problem? Or was it a torch with low insulation resistance? Oh of course you mean the batteries lost capacity because of memory effect! :44:

I do have a torch which gives inconsistent results - think it's because I've dropped it a few times!

 

[Deleted member 72666]

Re: Multi Function Tester with low battery giving very low insulation resistance read

Lol! When it happened previously it was not quite so extreme, and the MFT came with NiMH AA batteries, which as you will know have memory effect so I didn't want to keep topping them up and so reduce their capacity. Point taken though. Looks like I'll have to keep them topped up from now on!

I think you are confusing them with Ni-Cads as it's these that have the memory effect.

 

[Selfmade]

Re: Multi Function Tester with low battery giving very low insulation resistance read

I think you are confusing them with Ni-Cads as it's these that have the memory effect.

Ah - I thought it was both and only Li-ions didn't. Maybe I'll have a read around this...

 

[Silly Sausage]

Re: Multi Function Tester with low battery giving very low insulation resistance read

If these MFTs start dishing out dodgy readings on low battery power, maybe they should just down once the batteries reach a certain level.
It'd make sure you've always got a new set to hand, if you were 3/4 through an I&T on a Friday afternoon!

 

[Selfmade]

Re: Multi Function Tester with low battery giving very low insulation resistance read

If these MFTs start dishing out dodgy readings on low battery power, maybe they should just down once the batteries reach a certain level.
It'd make sure you've always got a new set to hand, if you were 3/4 through an I&T on a Friday afternoon!

Sounds like a good idea!

 

[ifindoubtdont]

Re: Multi Function Tester with low battery giving very low insulation resistance read

How about trying "Windup IR Testers" By GLENSPARK. No batteries needed. Problem solved.