Soap or Luck?

[cesranger]

Gentlemen, Seen something the other day and still can't explain it. Pulled a tough 400 ft plus, run of 4- 4/0 plus grd the other day, stalled a maxis 3000 and had to get the greenlee 8000 out to finish. Soaped every c to the max and keep wire soaped to the max. Finished the pull, cleaned up, and started to meg out wires. Heart sank and my ace drawed up, bad reading (meggar) on one conductor. Six thousand dollar pull at least. Called a friend and told him what happen, thoughts where to cut run in the middle and try to save at least half the run. Had another friend to tell me that a lot of soap can sometimes make conductor read bad and to give it a few days to dry out. At this point a would try anything, had a few days, so it could not hurt. Next day I megged wire ands reading got better, next day after that, even better and after four day bad reading gone. I energized panel the next day half thinking I would here a bang, not so, up and running fine. Go figure

 

[cadpoint]

Type of wire, type of conduit; above ground or in the ground?

I'm going to guess PVC in the ground, till you mentioned "C"'s :grin:

Frankly, I've always thought that the "soap" was made non-conductive!

 

[cesranger]

Wire is 4/0 copper, conduit 2 1/2 inch emt, and soap is non conductive. Any thoughts?

 

[ohmhead]

Gentlemen, Seen something the other day and still can't explain it. Pulled a tough 400 ft plus, run of 4- 4/0 plus grd the other day, stalled a maxis 3000 and had to get the greenlee 8000 out to finish. Soaped every c to the max and keep wire soaped to the max. Finished the pull, cleaned up, and started to meg out wires. Heart sank and my ace drawed up, bad reading (meggar) on one conductor. Six thousand dollar pull at least. Called a friend and told him what happen, thoughts where to cut run in the middle and try to save at least half the run. Had another friend to tell me that a lot of soap can sometimes make conductor read bad and to give it a few days to dry out. At this point a would try anything, had a few days, so it could not hurt. Next day I megged wire ands reading got better, next day after that, even better and after four day bad reading gone. I energized panel the next day half thinking I would here a bang, not so, up and running fine. Go figure

Well your fine we see it every time we pull feeders the megger reads bad like everyone thinks you must get infinity to be good not so ive turned on wire at less than 100 megg ohms and it has lasted many years . project managers say pull it out i tell him hold on watch this !

If you test bad less than say 25 meggs not a dead short its water dampness soap and yes soap is conductive ive can tell you it conducts . we clean the conductors up wipe them take hair dryer on the ends before we cut them and megg goes up way up morning low readings afternoon high readings your fine .

 

[LarryFine]

. . . bad reading (meggar) on one conductor.

I'd make that wire the neutral.

 

[don_resqcapt19]

Wire is 4/0 copper, conduit 2 1/2 inch emt, and soap is non conductive. Any thoughts?

It is my understanding that most wire pulling lubes are conductive.

 

[don_resqcapt19]

How many bends between the feeding point and the pulling point?
Did you clean the ends of the conductors before you megged them? Often the soap residue at the ends will give you a bad reading until it is fully dry, or you clean the insulation.

 

[480sparky]

It is my understanding that most wire pulling lubes are conductive.

So is the EMT.

 

[Jraef]

EVERYTHING is conductive! Some things are more so or less so than other things.

Pulling soaps used to use much less conductive wax based substances, but the formula had to change over the years with regards to flammability, toxicity, deterioration of specialized insulation etc. Many of the new polymers now have a water base, and water is one of those "more so" conductors. Once it dries, it becomes "less so".

 

[ohmhead]

Well if you put enough voltage to it anything will conduct the megger at 1000 volts is enough ! Just ask my helper he can give you lots of data to substantiate this and clear up the question .

 

[jrannis]

Type of wire, type of conduit; above ground or in the ground?

I'm going to guess PVC in the ground, till you mentioned "C"'s :grin:

Frankly, I've always thought that the "soap" was made non-conductive!

Non conductive when it dries!!

 

[cesranger]

Gentlemen, Thanks for your replies, I know this deal was a strange one. Soap I used said it was not conductive, hell I don't know, I didn't stick in meter in it. I had three other wires in same conduit that megged fine, they had just as much soap on them! I thought about changing and making it a neutral, but reading went away and I pulled the switch with good results. Been pulling wire for 30 years, never seen this and hope I don't see it again. I just wanted to pass this on, maybe it will help someone in the future.

 

[cadpoint]

Non conductive when it dries!!

Drum, drum, drum, OK, I looked of the MSDS sheet on the clear, I get it!

Silicon is a big part of the make up, along with a lot of other chemicals at I can say much less spell :roll:

 

[brian john]

What were your megger readings?

Beginning and now.

If you megged the conductors properly, ends isolated and cleaned and one conductor megged bad, you are in for trouble sooner than later.

As noted any non-conductive material can become conductive with contaminants.

In EMT with conductors installed I doubt drying happens very fast, just a thought.

 

[LarryFine]

I thought about changing and making it a neutral, but reading went away and I pulled the switch with good results.

I'll repeat that I would have made that conductor the neutral. If water ever enters or condenses in this pipe, that leakage may return, and slowly snowball over time.

While it's not ideal for even a neutral to have leakage, there would be (just about) no voltage to drive such a leakage current to begin with, nor start any carbon tracking.

 

[Chamuit]

I'll repeat that I would have made that conductor the neutral. If water ever enters or condenses in this pipe, that leakage may return, and slowly snowball over time.

While it's not ideal for even a neutral to have leakage, there would be (just about) no voltage to drive such a leakage current to begin with, nor start any carbon tracking.

I would follow that advice myself. There is a possibility that the insulation has torn from friction. Not necessarily enough to create a dead short but one big enough to allow a megger to read it.

 

[ohmhead]

Well lets say you have 11 runs of 750 mcm copper going to 5 switchboards each set of 11 go also to its own transformer now out of 55 runs two runs read 150 megg ohms from phase to ground or phase to phase the rest read infinity or the highest reading on megger scale .


Would you pull that run out?

Would you clean the ends meaning dry it up and retest ?

Would you turn it on ?

This has been happening for many years on jobs we do not to say the op has the same issue but what was his reading because at 1 megg ohm its good at 1000 volts a 600 volt conductor .

We always get 800 plus meggs on 20 % of the runs and the megg readings are around the same in one conduit plus or minus 100 meggs on different phase to phase conductors we isolate each end and test open ends mostly 80 % is infinity high readings a few are low like 50 meggs we dry up ends we cut 1/2 inch off ends and the megger goes way up from 50 to 500 meggs .

We found that when you pull wire underground in a conduit water enters the jacket this water gets into the insulation we also found that at 100 meggs that most people pull it out we dont we turn it on and the load and current flow heats up the water or damp/ wet or soap that gets pushed down that jacket if we dont see a major up in the meggs we pull it out and install new conductors but thats rare its always good and holds and after a week we shut down power and re megg the ones that were low and its still high and sometimes its a higher reading then before . We get to play with this because we only do new work so we can go back after a week or two and retest were on site for a long time from start to finish .

Done this for many years and never a recall on any feeder yet . And we know when its bad when that megger doesnt come up or it doesnt hold stable we pull it out roll it up and ship it back to the supply house .

Many years back we use to save it but needed to fined that spot we put bisquee in a hole in the ground fill it with water and pulled the bad conductors thur megg it every 10 foot when it meggs bad thats the spot if we found a tiny nick not a cut to conductors just a tiny nick wed shrink tube a 3 foot section and its now a good run ready to repull but we dont do that anymore they send us a new roll today .

 

[mxslick]

I would follow that advice myself. There is a possibility that the insulation has torn from friction. Not necessarily enough to create a dead short but one big enough to allow a megger to read it.

I agree and see a major outage in the future. The fact that the OP had to use so much pulling force tells me there is conductor damage.

Larry's advice would help postpone the inevitable, but then you could be facing an open neutral situation.