melted neutral bus bar

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mike33

Member
Location
Irvine, CA
The neutral bus in a Jandy sub panel melted. Was replaced by others. Then melted again. Then we were called. I personally have not seen it yet, but I trust the source describing it as melted. This panel feeds all the pool equipment. The HO says the problem only happens in the rain. No breakers tripped. The neutral supplying the sub panel was checked and is tight.

Any ideas of what could cause this? Could the neutral wire between the main panel & sub be damaged? Maybe shorting to ground? :confused:

Related?.... There is no cold water bond and the #6 copper ground wire ufer was very loosely connected to the #4 from the panel.
 

Besoeker

Senior Member
Location
UK
Harmonics can cause neutral overloading. But difficult to see how that would correlate to it only happening when it rains. But, maybe that's a red herring? The neutral has melted twice. Has it rained just twice since the panel was installed?
Can you measure the neutral current?
 

infinity

Moderator
Staff member
Location
New Jersey
Occupation
Journeyman Electrician
I agree with Dennis more information is needed. If this isn't part of a 3 phase Wye system then harmonics is out of the picture (I'm not even sure that pool equipment could generate harmonic currents). A few photo's might help too.
 

brian john

Senior Member
Location
Leesburg, VA
1. Measure the neutral current.
2. Tightening a bad connection does ABSOLUTLY NOTHING.
3. Is this a sub panel? Check the other panels. Primarily neutral ground issues.
4. Is the neutral bonded in this panel?
5. Are the branch circuit neutral free of neutral to ground shorts (MEGGER and clear all neutral to ground short.
6. Just because it was fixed before does not mean the new termination bar was installed properly.


When I have seen this in the past the issue was all the neutral current was on the 10/32 bond screw. The neutral for the panel was open.

I would doubt harmonics and/or rain.
 

spikes2020

Member
Location
Nashville, TN
I agree with Dennis more information is needed. If this isn't part of a 3 phase Wye system then harmonics is out of the picture (I'm not even sure that pool equipment could generate harmonic currents). A few photo's might help too.

I'd like to see some photos of a melted neutral bar too :grin:
 

marti smith

Senior Member
Check your phase to phase voltage as well. I had a service call once where the installed subpanel was fed both phases from one single pole breaker in the main. The neutral bus was in the shape of a jello mold- and toasty.
 
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