meters not accurate below 0.01 ohms

[peterhardacher]

That's very helpfull thanks tony these are expensive wonder how much to buy ? This is a great starting point for me even though my firm should be telling me this not other way round lol but knowledge is power and if they want my signature they need to provide the correct equipment for me to do my job

 

[Knobhead]

I’ve had access to a ductor at all the companies I’ve worked for. It’s an invaluable bit of kit.

 

[peterhardacher]

There only 3500 haha

 

[Bobster]

The megger ltw 425 on that site is the loop tester i use which measures down to 0.001ohm. Only £379 an that's without discount.

 

[ian.settle1]

Max ZS on a 400 amp fuse for a 5 s disconnection time is 0.096 and higher fuses are. Lower

Which is 9.6 times higher than 0.01

 

[peterhardacher]

I ment 0.1 ohm haha this is the reason I post on here cos its good to chat to other guys bout these things and to get ya mistakes pointed out lol ( no o es perfect ) . I be honest I had not heard of this it was a another of the lads to mention this which has lead me to do some research and start asking some questions

 

[peterhardacher]

Am I totally mis informed about this 0.1 ohm accuracy thing ?? Has any one else heard of this

 

[Sintra]

OP have a look at the attached file.

https://www.dropbox.com/s/tlgl6xsxunrwzf8/Megger Low Resistance Testing.pdf

 

[peterhardacher]

Thanks some useful information there

 

[vaughant]

My megger meter went to 4dp,would have been fine for the job.
think it's a megger 286 from memory,were about £500 a few years back.

 

[Engineer54]

My megger meter went to 4dp,would have been fine for the job.
think it's a megger 286 from memory,were about £500 a few years back.

I think you may be right, and sounds like the unit we have used on past projects. But i can't remember the actual model number either!! lol!!

 

[Engineer54]

I'm not seeing much of a point in using a Ductor tester to measure Ze to be honest, you would need much more information than the values measured with this device. You'd need some very long test leads too in most circumstances, and a fair bit of calculation if you do happen to be in possession of all the other relevant information!!

I use these testers to determine contact resistances of say Switchboard buss bar joints, contact resistances of ACB/GCB and larger MCCB breakers etc, and basically anything that has a sizable and/or critical site made joint/connection and the like!! Like Tony, i wouldn't be without a decent Ductor test kit during testing/commissioning sub-stations and the like!!

 

[Knobhead]

I had an electricians mate, his job was to run out the 70mm test leads.

 

[jams88]

A ductor tester might be much more accurate for measuring lower resistance ..

 

[Knobhead]

Please stop digging up old topics.