Underground megger test not passing

[K8MHZ]

Oh,

And once they passed we put plastic bags over the ends and taped them as far down the down the conductor as we could, leaving the clean, dry ends un-taped. They would stay that way until the termination crew got there. What would be the point of getting the ends all nice and dry just to have them get wet again?

 

[TimK]

Just as a forethought, why not use heat shrink caps prior to pulling, standard practice for wire over 250 and underground conduit that is installed in a WA raining season.

 

[K8MHZ]

Just as a forethought, why not use heat shrink caps prior to pulling, standard practice for wire over 250 and underground conduit that is installed in a WA raining season.

I don't think that would have made much of a difference, as it's my opinion that the ends got contaminated during the pull and / or after, where the pulling crew would leave most of the heads on and move to the next pull. We had hundreds of conductors 250-350's and installing them was set up like a factory. There were separate crews for everything. And, since most of the pulls were 100 - 200 feet long, lot's of yellow 77 was used. So, the heads were wet and full of yellow 77, black tape and duct tape adhesive. And they would sit that way until my crew came along and cleared them. Then another crew would come along and terminate them. The 5 kv stuff got megged twice. Once before the stress cones were put on, then again before the hi-pot testing was done.

 

[brian john]

I have a megger that the scale is reversed upon setting the meter to the 'meg' setting. It has other resistance settings like an ohm meter, but the scale is backwards.

It's an older analog meter. Really confuses the guys used to a digital meter. Set to ohms, a 'pass' would peg the needle to the right, set to meg, a 'pass' would peg toward the left.

I do not consider that backwards that was ther norm with all analog meggers I have owned.

 

[don_resqcapt19]

I do not consider that backwards that was ther norm with all analog meggers I have owned.

Yes, you just have to pay attention to the scales on the meter.

 

[K8MHZ]

I do not consider that backwards that was ther norm with all analog meggers I have owned.

By backwards I meant to someone that never used one before. There are many out there that were trained on a digital meter and never got to use an analog meter.

You are correct. I have an AVO/Megger and a Sanwa and both are the same. I also have one with only one scale. No silly buttons to push, either. You just crank like there is no tomorrow (please note date of this post) and read the scale.

 

[don_resqcapt19]

...I also have one with only one scale. No silly buttons to push, either. You just crank like there is no tomorrow (please note date of this post) and read the scale.

And if the item being tested is bad, you don't even have to look at the scale...you can tell by feel...it doesn't get easier to crank like it does when the item under test is good

 

[hillbilly1]

If what the others have posted does not work, you may have a bad spot in the conduit run that has damaged the new cables also. The arcing can melt the conduit whether it be PVC or rigid steel. Since you were able to apply 120 to the cable, check for any current flow, if there is no load on the cable, there should be no current. If you do have current flowing, you definitely have a problem.

 

[brian john]

By backwards I meant to someone that never used one before. There are many out there that were trained on a digital meter and never got to use an analog meter.

You are correct. I have an AVO/Megger and a Sanwa and both are the same. I also have one with only one scale. No silly buttons to push, either. You just crank like there is no tomorrow (please note date of this post) and read the scale.

And for some test crank and crank and crank..............

 

[K8MHZ]

And for some test crank and crank and crank..............

No doubt. Can you imagine a 30 second test on hundreds of conductors.

Just carrying the thing around would have been a crappy job.

I got mine brand new. Around 2004 or so. It's a chinese product (not a knock off, they still used them there when I bought mine) and it's built like a tank. I got it new, unused, but it didn't work. I made arrangements with the seller for a replacement if I couldn't fix it. Turns out the tiny shaft conected to the needle in the d'arsonval movement was bent. I gently coaxed it back to straight and it worked. I 'calibrated' it using my other meggers and it's right on.

I have no plans on taking it into the wild. It's more for show and tell. It's very rare to see a 1000 volt cranker in brand new condition.