Insulation resistance 0.00megger ohm

[davetheglitz]

TBH I am loosing confidence with the training in this industry

Rest assured the lecturers find this just as hard! It's the exam boards and colleges that need to review their practices.

One re-take per exam per year and off the course on the second failure would go a long way to sorting things out.

As it is a number of level 3 students can't do basic maths, are still unable to draw a 2 way lighting circuit and haven't got the first idea of how to fault find. How many times should a lecturer have to teach basics? If the students have no motivation to learn then the best lecturer in the world will get nowhere.

Having said that a lot of these students have good hand skills - why aren't we pushing what they can do rather than highlighting what they can't!

 

[Apache]

Oh, an afterthought. people have died in hospital because of the maladministration of drugs, based upon a common misunderstanding of the difference between cubic centimetres and millilitres.

I disagree. I cubic centimetre = 1ml.

People die because medics get decimal points in the wrong place; we have drugs in mg, micro grams and sometimes (just for a real hoot) international units! Then add into the confusion in the uk solutions are usually quoted in mg/l but the Americans like to use mg/dl just to add a factor of 10 confusion in there......

 

[Technician]

I disagree. I cubic centimetre = 1ml. People die because medics get decimal points in the wrong place; we have drugs in mg, micro grams and sometimes (just for a real hoot) international units! Then add into the confusion in the uk solutions are usually quoted in mg/l but the Americans like to use mg/dl just to add a factor of 10 confusion in there......

Thanks for the forensic explanation Apache;

That is the point that needed making.

 

[ProDave]

As it is a number of level 3 students can't do basic maths, are still unable to draw a 2 way lighting circuit and haven't got the first idea of how to fault find. How many times should a lecturer have to teach basics? If the students have no motivation to learn then the best lecturer in the world will get nowhere.

This bugs me.

I went into electrics, because right from an early age, I found I understood electrical circuits, understood how current flowed from a to b, and how things like switches worked. It all just seemed so logical and simple.

So why is it that people with seemingly no interest in, and certainly no natural ability in electric circuits, choose this as a career, then struggle to understand what they are taught?

I chose not to be a doctor or chemist because those things did not come naturally to me so it would have been a hard struggle to learn and I would never have been any good at it.

Have careers advisers stopped finding out what people are good at? or perhaps they don't exist any more?

Oh of course, I'm forgetting that now anyone can learn anything and they can't possibly fail as that would be against their human rights :coat

 

[professional]

Did you careers advisor push you towards being any sort of artist then? ]

 

[ProDave]

I think I have my parents to thank for my education being successful.

My father was a plumber and wanted me to follow him into that trade, but accepted my interest in electrics.

When it came time to go up to the next school, at a meeting with the school I was supposed to go to, my mum mentioned my interest in electrical things and asked if the school would encourage it. She didn't accept the reply of "oh don't bother about that it's a passing phase he will grow out of it" so made a fuss and ensured I went to a different school who were interested in encouraging natural ability.

 

[sellers]

the problem with schools today is that they prusue the idea that if you don't go to uni you are deemed a faliure and bad for their stats. Thats how I was treated, still I'm the one earning the coin while the others have useless degrees looking for shop work.

 

[Mr Smith]

mr smith must apologise for his tardiness

the posts pertaining to the moderators have been moved to a new thread

mr smith is unable to perform the necessary wizardry to include a link

 

[Andy™]

mr smith must apologise for his tardinessthe posts pertaining to the moderators have been moved to a new thread

mr smith is unable to perform the necessary wizardry to include a link

you mean this thread

 

[lineman]

Nick1986 did you find the fault!?

 

[unphased]

Just been thinking about this 0 Mohms 0 ohms post made #2.

Zero anything is zero.

If somebody said to you 0km would you assume it was 1m to 999m? I wouldn't!!! 0km is 0m is zilch. The way Special Location went ranting on and on about 0Mohms being 999 ohms was astonishing to me. :Blushing Quick edit quick quick...phew...Sorry SL the error of my post has been pointed out later in the thread.

Edit quick quick 1,000,000 ohms is 1Mohm. My Megger MIT310 measures insulation resistance in Mohms. All insulation testers measure in Mohms. So, when it reads 0.0 its a dead short. 0Mohms. If it is calibrated to read Mohms then it IS 0 Mohms. 999 ohms is 0.999 Mohms bit it would probably read 0.99 (two decimal places), and will read down to 0.01Mohms or 10k ohms. It actually tops out at 999Mohms which is perfect 100% insulation test. 999Mohms or 999,000,000 ohms. But when it reads zero it is just that.

If you weighed a bag of widgets and they weighed 1kg then took all the widgets out it would be 0kg not 999grammes.

So when the OP said 0Mohms he was correct. Let the fun begin. :run

 

[lineman]

I think he was highlighting the scale of 0.00Mohm. Thats what I got from it anyway.

 

[m4tty]

I believe you have misunderstood Roy but I can't explain it ffs. Just tried writing it out to explain but I'm useless at explaining. 0.01 megohm is the smallest the meter can read which is still 10k ohms. I'll let someone else explain it lol sorry

 

[Zeespark]

Me too, and not 999 ohms either, more like a million.

AndyGuinness

 

[m4tty]

SL wouldn't get something like that wrong mate. No chance

 

[Zeespark]

Nope, He, along with other esteemed members here, has been a absolute library of info on here since they all signed up.

AndyGuinness

 

[unphased]

Yes, matty. 10K ohm is 10,000 ohm. My meter reads in steps of 0.01M ohm or 10k ohm but when it gets in to the 100M ohm territory it just reads whole M ohms.. So if the scale is all in Mohms then 0 Mohm is a valid 0. LOL!

EDIT: SL is CORRECT!

 

[m4tty]

A dead short can only be read on continuity range not the ir range. The scale won't go low enough ?

 

[Sidewinder]

unphased,

You are correct that 0 is 0.

However, the instruments that are used by installation electricians for I&T on fixed installs have significant limits.

Thus, they cannot resolve sufficiently on the Mohms scale to give you a reading in ohms.

Thus they round down to the limits of their resolution, which when you thing about rounding of numbers after the decimal place, x.0 to x.4 you will round down to x, x.5 to x.9 you will round up to y, where x+1=y.

So if you take an average MFT, it has a resolution of 2 decimal places on the Mohms scale.

Taking that 1Mohms - 1,000,000ohms then the minimum resistance value that the tester can display is 10,000ohms, that is 10kohms.

Thus by the rules of mathematical rounding, any resistance measured which is less than 9,484ohms would be reported as 0Mohms.

Does this explain things a bit better?

 

[unphased]

ok, I'll accept that one matty, so you are saying that inreality the meter won't measure less than 0.01 Mohm so it could be anything from 999 ohms down to zero. Yes?

Yes sidewinder it does. I am the plonker.