what class?

[swelectric]

I have a building at a wastewater treatment plant that is not in a class 1 area by definition but the fumes from the area are changing the wiring color to brown. While this is not explosive it is corrosive in my opinion. Has anyone dealt with this and have any ideas about what to do with it.

 

[coulter]

I have a building at a wastewater treatment plant that is not in a class 1 area by definition but the fumes from the area are changing the wiring color to brown. While this is not explosive it is corrosive in my opinion. Has anyone dealt with this and have any ideas about what to do with it.

If it is the copper that is changing color, it's likely H2S. If it is the insulation that is changing colors - I haven't a clue.

I worked at a sulphite pulp mill for a while. We used a lot of plastic 4X boxes. For Class 1, Appleton males a gasketed, fiberglass, switch box - doesn't leak!

Of course, supplying outside air for ventilation works well.

carl

 

[rbalex]

I would also like to know if the reference is to the conductor or the insulation. H2S is a Class I, Group C material, but it doesn't take much H2S to discolor copper - it could still be below the LEL from a classified location perspective. It is moderately corrosive however and would be covered by Section 110.11.

 

[roger]

I have nothing to offer as far as a cause or solution but I have seen this same thing in a semi below ground pool equipment room with high chlorine content, it would burn your eyes and throat.

I don't think it ever caused any problems for the conductors, but the panel interior had to be replaced every couple of years.


Roger

 

[petersonra]

I used to work at a place that built a fair number of control panels for use in paper plants. they have some really unpleasant conditions, but often not anything requiring area classification, at least for the equipment we supplied.

Most of the plants specified FRP enclosures with instrument air pressurization to keep the nasty environment outside the box.

I am told that even 316SS boxes would corrode heavily on the outside when used in this environment, but the pressurized air kept the inside of the enclosures like new.

YMMV.