Washdown Environment

A few months back i posted in the panel building thread about washdown environments and suggestions,,and now that ive been in the environment a few months,,figured id revive the issue with a thread in hopes it may help others and spart up some interest,,


first off id like to say that ive never encountered so many problems due to water,,anything from taking motors down and out to water in actuators causing 'ghost' problems that took some time to troubleshoot,,

here are some things im trying to implement around here to limit downtime,,

1. Holes at the bottom of electrical boxes to allow water to drain,,

2. Drip loops on wires

3. Not focus so much on sealing the hell out of electrical boxes being sanitation in their tenacity will find a way to pressure wash their way into them,,but focus on letting the water not accumulate,,

4. Regular inspection of Pecker heads,electrical cabinets,,etc

Any other suggestions would be appreciated,,Im sure Elevmike has something to throw in,,

gotta floor call,,box machine down!!!!

Fred Raud

Fred,

If I remember that thread correctly I think my biggest issue was the fact that you will get moisture in the conduit system no matter what you do to try to seal it out. So when installing the conduit and boxes, make damn sure that all the pipes and installed in such a manner so that all moisture will accumulate in areas where it can be removed or drained. Throw away the level and slightly grade all the horizontal runs and boxes.

I agree with Mike. Design the conduits and boxes as if water WILL get into them. Figure out what to do with it when it does get in.

I had bad problems with moisture and corrosion when I worked for a chemical fertilizer plant. Any water caused the fertilizer to become corrosive, and also conductive. I thought that was bad, but it is nothing to what I saw at a potassium carbonate plant. That has to be the worst environment for electrical devices. Pot carb will enter a wire at the termination point, and slowly migrate up the wire inside the insulation, eating away the wire and leaving a perfectly nice looking cover--that is completely rotten inside. It also will find the smallest pin hole in the insulation, and form a bridge from the wire acrosss the insulation and connecting to any other conductor in the area it happens to settle on, such as the edge of metal boxes or conduits. Then the insulation becomes a conductor, and you get a nice little surprise when you go in to troubleshoot.

Eventually the pot carb dust migrates into the best seals and shorts out the motors, the switches, and even the light fixtures. If I got a cut or scrape on my hand, the pot carb would burn like fire. I would wash it off and it would stop hurting, but a week later, a big hunk of skin would turn black and rot off, just like a rattlesnake bite.

The only way I ever found to slow pot carb migration down even a little bit was to fill all the junction boxes and conduit fittings with a 3M gasket sealer. I don't remember the model, but it is the one that never gets hard, but stays jelly-like. We bought it in 5-gallon buckets and filled every opening we could find. It kept out water completely, and even pot carb--for a few months.

EDIT: Some of you are wondering what potassium carbonate is used for. It is an additive for dairy cattle feed. The stuff is so water absorbant that it makes the old cows very thirsty. They drink extra water, which gets turned into more milk. It is rough duty for the cows, but nice for the dairy farmers.

Lancie1 said:

EDIT: Some of you are wondering what potassium carbonate is used for. It is an additive for dairy cattle feed. The stuff is so water absorbant that it makes the old cows very thirsty. They drink extra water, which gets turned into more milk. It is rough duty for the cows, but nice for the dairy farmers.

Click to expand...

and i thought maybe you were just a friend of Timothy McVeighs!!!lol


Fred Raud

As i have said in the past. A water proff enclouse just stops the water from getting out..I cant count the amount of stainless steel waterproof discoinect switches i have opened and a flood of water came out..

i did find that drillings holes in the bottom switches helped but also found that sometimes they get plugged up..if you have the hieght and the space drill a half inch conduit and leave a 10" tail sticking out of the bottom..Its a good drain and long enough that the water "Splash" dosnt get in..

I worked in a poulty processing plant a few years back...


We found that we had to pipe (dry) compressed air into motors to positively pressurize them to keep water out.

We never terminated conduit at a box or switchboard... All conduits were open-ended to allow water out...We always used multicore double insulated cable ("orange circular") and our boxes just had a cable gland that sealed water out.

Our maintenance plan was that every junction box, motor isolator, etc would be opened up and dried out every 6 weeks...Any longer increased the risk of a failure due to water.

darrenj said:

i did find that drillings holes in the bottom switches helped but also found that sometimes they get plugged up..if you have the hieght and the space drill a half inch conduit and leave a 10" tail sticking out of the bottom..Its a good drain and long enough that the water "Splash" dosnt get in..

Click to expand...

2 days ago we had a motor start tripping a inverter on over current and upon inspection of the peckerhead,,found that the seal to the gearbox was bad and had flooded the motor with oil,,and being the gearbox/motor was installed at an angle with the motor downward,,the motor got pretty full of oil,,well,,today was our downday and i pulled the motor off and changed the seal and while it was all apart i went ahead and drilled a 1/4 inch hole in the peckerhead cover to allow for water/oil to drain in the future,,after looking at it installed,,i could just see a guy from sanitation seeing that hole and treating it as a bulls eye with his water hose,,so i found an oring that fit perfectly in the id of the hole with a small bolt in the middle and had enough pressure to hold it in but could be easily pried out with a screw driver in a situation that may arise,,or simply removed with a small nut driver or wrench,,i may go back and tap it and put a vent type fitting on it so oil can drain freely and will give less chance to get water in it,,but i hold reserve due to our place having a guy come in on sundays with some 'stainless steel paint' and painting everything with rust(and of course data plates,,holes,,etc,,)and can see it not lasting as a drain,,at anyrate,,my thinking is that though today it is implemented as a possible drain/indicator of/for oil seal leak,,tomorrow it might be a good place to allow water to escape,,


Fred Raud

Your idea of having drip / weep holes in the boxes is similar to what Square D does with their Nema 12/3R disconnects. There is a screw in the bottom that you remove to make it a 3R. Look at how they do it to get the water of drip out this hole while limiting water getting in.

For the motor connection boxes (peckerheads) try using the packing material / putty that is used for dusty environments. Something like this? http://catalog.graybar.com/servlet/BugsEye

I have been working in a Case Ready Meat plant for the past 3 yrs, we run a 20hr production, 4hr sanitation schedule 7 days a week.

For electric motors have found nothing better than the Toshiba "ToshWash". It comes with 3 drain plugs, one for the peckerhead and 2 for the motor to be installed after mounting to the gearbox in the lowest position of the motor. NOTHING BEATS HYDRAULIC MOTORS FOR CONVEYORS, have a look at a company call TECH-ROLL.

Use coated conduit and at every control box put a "T" condulet and run a drip leg from the lowest connection to the "T" long enough and close enough to the floor so the sanitation guys (HOSE MONSTERS) cant get their spray up it.

if you were in a position to design a new production area, build a plenum area above the production floor and put all contol boxes out of waters harm, and only run switches and motor leads down to the "wet area"

Hi;

In the fish processing industry we have these problems as you descibe. There does not seem to be any one solution. We have started pushing for a few simple guidelines for panel design.

Where ever possible use only bottom cable entry. Most electricians will put up a fuss when you enforce this rule put it is worth it. It stops water from dripping down over the gear when it comes in thru conduit. Adding some heat to the cabinets also helps to overcome the condesation issues. In a perfect world a cabinet should not even have pilot devices on the door.

If you ever find a way to keep high pressure cleaning water out of cabinets you will be a rich man. I am sure the cleaners have running bets about how much damage they can do.

Jim