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#185209 - 03/05/09 10:14 PM neutral no antioxident  
watersparkfalls  Offline
Member
Joined: Mar 2005
Posts: 216
Washington...Not DC
Well here is a scenerio I haven't yet seen.
I went to look at a 200 amp panel service call. And discovered the neut appears to be overheating and melted some of the plastic of the neut bar holder(to float if a sub pnl which this isn't)I wiggled the 2/0 and it seemed very tight, tried to tighten lug it would'nt buge(didnt thik it would after that kind of heat)so I removed the bubble from the meter socket to see if the load side neut was loose.... only to find PSE(puget sound energy)neutral on the lineside was oxidized badly and had black on its 2/0 aluminum wire. Also no sign of anti-oxident used by wiremen on original install. I can see the electrician used it on the load side and in the panel too.

So is this the power company's fault? or is there something I am missing?

Thanks,
H20


2017 / 2014 NEC & Related Books and Study Guides

#185211 - 03/05/09 11:04 PM Re: neutral no antioxident [Re: watersparkfalls]  
WireNuts29  Offline
Member
Joined: Jul 2007
Posts: 85
Mass, U.S.A.
2/0 on a 200 amp???...maybe there's your problem.. anti-ox is not a code requirement. not sure oxidation would cause wire to burn up until its real bad, usually a loose or poor connection will burn up.


#185222 - 03/06/09 02:29 AM Re: neutral no antioxident [Re: WireNuts29]  
watersparkfalls  Offline
Member
Joined: Mar 2005
Posts: 216
Washington...Not DC
Originally Posted by WireNuts29
2/0 on a 200 amp???...maybe there's your problem.. anti-ox is not a code requirement. not sure oxidation would cause wire to burn up until its real bad, usually a loose or poor connection will burn up.


The 2/0 is the neutral conductor.....no problem.

anti-oxident is acually required per 110.14....
I know it says where employed and this is a well debated topic. But it is required, if you look at the specifications from all wire manufactures they say to use anti oxident thus we are required to install according to manufactures instructions.

I think this was a clear example of anti oxident vs no anti-oxident.

But how come inside the panel, the neutral lug was overheating...when the weak point was the line side neutral in the meter?

Just wondering what you guys think, seen, know, feel, beleive could be the cause of this problem.

Thanks,
H20



#185224 - 03/06/09 02:58 AM Re: neutral no antioxident [Re: watersparkfalls]  
gfretwell  Offline


Member
Joined: Jul 2004
Posts: 9,105
Estero,Fl,usa
I bet it was loose, right where it burned up.
Nobody really seems to torque these lugs it seems, at least not in residential.


Greg Fretwell

#185230 - 03/06/09 07:47 AM Re: neutral no antioxident [Re: gfretwell]  
sparky  Offline
Member
Joined: Oct 2000
Posts: 5,311
Quote
Just wondering what you guys think, seen, know, feel, beleive could be the cause of this problem.


well i don't believe any connection is forever proof H2O. Consideration to it's mileage in climatic conditions is usually relevant.

myself, i'm in older equipment all the time doing the '$5 tune-up' quickly checking all connections

that said, it's done via screw driver/allen wrench. anyone going to go down cold flow ave with this....?

~S~


#185460 - 03/15/09 01:42 PM Re: neutral no antioxident [Re: sparky]  
KJay  Offline
Member
Joined: Nov 2007
Posts: 763
MA, USA
I'm still not really comfortable with the aluminum wire industry statements about not needing antiox for connections in dry locations with the current aluminum cables.
Seems like this is always the kind of thing that years later, the industry will announce that there is a problem with installations done this way in the past.
They do say to use antiox where moisture is present though, like outdoors in a meter enclosure.
I personally use it one every connection regardless, along with a torque wrench, but they also warn not to wire brush the cables as we used to years ago.
I still find occasional use for a wire brush though on older OH service drops, direct burial cable repairs and old SE cables used for branch circuits when doing panel changes.




#185461 - 03/15/09 06:05 PM Re: neutral no antioxident [Re: KJay]  
EV607797  Offline
Member
Joined: Oct 2006
Posts: 745
Fredericksburg, VA, USA
What they say today about not needing anti-oxidant may have to do with the fact that today's "aluminum" cable is an alloy, not pure aluminum like it originally was. Today's alloys are much more stable than pure aluminum. I still use anti-oxidant, no matter what. I even use it on meter jaws to act as a lube when plugging them in. I've been known to use it on copper too in damp or corrosive environments. I really can't see the harm.


---Ed---

"But the guy at Home Depot said it would work."

#185464 - 03/15/09 09:59 PM Re: neutral no antioxident [Re: EV607797]  
sparky  Offline
Member
Joined: Oct 2000
Posts: 5,311
just out of curiousity, what would this group say about Copper anti seize for copper terminations?

~S~


#185466 - 03/15/09 10:21 PM Re: neutral no antioxident [Re: sparky]  
renosteinke  Offline
Cat Servant
Member
Joined: Jan 2005
Posts: 5,316
Blue Collar Country
Officially? Not listed for the use, therefore to be frowned upon by inspectors, etc.

Unofficially? Quite commonly used in corrosive or high temperature applications, especially on fittings.


#185481 - 03/16/09 04:14 PM Re: neutral no antioxident [Re: renosteinke]  
KJay  Offline
Member
Joined: Nov 2007
Posts: 763
MA, USA
Not to wander off topic, but now that it has been mentioned, I'll bet something like that T&B Kopr-Shield would also be great to help maintain conductivity for smaller stranded wires terminated on circuit breakers in panels located in pump houses, sheds and outdoors.
I often see discoloration and verdigris between the copper strands after a few years in these locations. When I remove these wires from the breakers I find that this oxidation migrates through the strands and under the screw terminals often creating high resistance connections resulting in heating that leads to melting of the insulation near the breaker terminals.
I don't know who stocks it and can't find any info on the T&B website as to whether it UL listed or not, but the product description indicates that this is what it is designed for, so I will have to look into purchasing some and give it a try.
I did find the T&B Contax inhibiter though. This is a black grease like product, which the instructions say is for use on connections with all wire types so, this could probably work in this situation as well.



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