corrosion in meter lugs

[Stevenfyeager]

I noticed corrosion inside one main breaker lug in a panel, called the utility company and pulled the meter, there was corrosion in one load meter lug. Then after the utility co. left, I noticed corrosion in the same side line meter lug. (I'm assuming the same phase as was inside the panel.) I'm going to have the utility come back and check the overhead connection too. Why would white corrosion be only on one phase side of each of 3 lugs? 100 amp service with #4 Copper wires everywhere? Thank you

 

[ActionDave]

Interesting. Was the corrosion only on the lugs? What was the condition of the conductor on that phase?

 

[GoldDigger]

Possibly there was a residual DC component on one phase line for some reason.
That could cause visible corrosion of one of the two touching metals only. But it would still require a moist conductive environment.

 

[JRW 70]

Condensation

Condensation

We have trouble with some of our SCADA system
control boxes. They are gasketed panels and the
residual moisture combined with day/night thermal
changes is enough to cause corrosion. This doesn't
explain the localized residue, except if that phase
line were somehow at a different temp. than the rest
of the panel.
Does this panel have a little ventalation to keep the
enclosure at the outdoor temp? Or are they like I
described above? There are a few options to help
control this: (a) use ventilation to keep the inner
and outer air at the same temp. ( just passive
flow from the temperature variation between inside
and the surrounding environment air )
(b) use anti condensation heaters to keep the temp.
above the dew point.
(c) use a desiccant to absorb the moisture. ( which
have to be periodically changed )
And none of these may work depending
on the meter base ( too little room )
I put these in order of required field maintenance.
And finally, are there any corrosive chemicals
used/stored in the area?

JR

 

[kwired]

Is the connection to service drop conductor below the weatherhead? If not does the conductor at least have it's end pointed downward so water can not run inside the conductor insulation and leak out at the bottom end at the line side meter terminal? It could be dripping from line side onto load side and following inside insulation of that conductor on into the service disconnect.