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sub station feeders weeping

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caporter

Electrical
Nov 7, 2008
28
I have inherited two older substations with woven insulation on the 13,500V feeders. The wires are weeping some kind of fluids. The most common is brownish with a high viscosity. The other fluid is green and looks like water and copper corrosion to me. Do you have any idea what the brown fluid is and is it something I need to worry about?

 
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I've seen similar 'green goo' in some of our older stations. I think the copper in the conductor reacts with the insulation and some of the copper actually creeps out of the conductor. the result of the chemical reaction is a 'green goo.'

You should also be aware that some of this 'green goo' has been identified as a potential PCB hazard.

 
First of all it seems to me that is a distribution of 600 V with cables type XHHW-2 [crosslink polyethylene insulated].As the lugs are relatively new some one changed the old lugs due to overheating and fixed the damage jacket of the incoming feeders with woven tape.
The cable inner filling and the jacket is PVC made and insulation is XLPE [crosslink polyethylene].If the PVC is overheated the melted material may dip down.
You may check the contact between conductor and the lug. If the temperature is low or moderate and if you don't intend to lay another cable instead of the old I think this arrangement will remain in operation for another long time.
 
7anoter4 you are correct that this is the 480V distribution side. Only some of the wiring is XHHW, it was installed some time in 2003 after some of the wire with woven insulation failed.

I'm thinking the green fluid indicates corrosion and a possible failure point. I'm not sure of what to make of the brown fluid. The link below shows a picture of the cables that were replaced in 2003. The cables from the feeder that failed are heavily soaked in the brownish fluid and the insulation on the cables from the feeder you seen pictures of are mostly dry.

 
PVC insulation is made fexible with plasticisers which are, essentially, oils that dissolve the PVC. It seems your cables may have gotten hot. This can cause tthe plasticzer to migrate out. Heat will also degrade PVC and release hydrogen chloride which will corrode copper, producing green-colored corrosion products.
 
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