R-u-s-t

To give a better view of the situation, I am posting a picture. This is just 1 of the 4 RTU found nearby the plating machines. All 4 are exposed to the contaminated air (chemical fumes), although they are contained in a chemical resistant box, the box has no cover. This RTU connects to a PLC, which is 10-15m away.

I would like to propose replacement of the panel box to a NEMA type 7 enclosure & contact cleaning. Will that be enough?

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Ripley

IF everything is still working I think I would be tempted to hold off until I got all the right stuff to deal with it.

You can put these in plastic boxes and leave all in the environment. Vapors including water can go thru plastic. Granted it is on a molecular basis but they will do it. Best and closest example is oxygen getting thru PEX tubing wall.

1. It appears to be rust on the screws. Check to see if they are steel. If so I would for sure replace them and also consider replacing with brass or stainless steel ideally SS 316.
2. I would use an anti oxidant. I have had good luck with No Alox (by Ideal ??) on battery terminals, in a marine environment and other harsh conditions. Yes I know it is for aluminum wire but it has worked quite well on Cu and Cu Al connectors. No Alox your new screws and the thread of the terminal. You can get an anti oxidant for copper if you want. Thomas & Betts makes it I believe.

3. On existing crimp terminals I would consider soldering them - do NOT be cheap with the flux. Deenergiz them of course. DISCONNECT them - do NOT solder in place.

4. On new terminations I would at minimum use anti oxidant on wire and terminal to be crimped or maybe take the time to solder them. You can crimp before solder at your choice.

An argument is often made that you cannot solder them. Some even quote the NEC which does state connections cannot rely on solder alone. I counter argue that I have seen circuit boards with 30 amp fuse clips soldered in - worked like a charm. IF you have the right size wire and connector you should have no problem. Insulation is often rated for 105 C which is in low 200 F range. Solder melts at 400 plus if recall correct.

Pictures are worth 10,000 words. Yours saved you bunches of typing.

ACRONYM ALARM -- NEC stands for National Electric Code.

Dan Bentler
 
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leitmotif said:
2. I would use an anti oxidant. I have had good luck with No Alox (by Ideal ??) on battery terminals, in a marine environment and other harsh conditions. Yes I know it is for aluminum wire but it has worked quite well on Cu and Cu Al connectors. No Alox your new screws and the thread of the terminal. You can get an anti oxidant for copper if you want. Thomas & Betts makes it I believe.
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Given I do this, what will be the frequency of application? I am concern since my client wanted a less maintenance solution if not permanent or maintenance-free. They, basically, do not conduct any PM (preventive maint.) on their machines, which is absurd given the toxicity of their production area. I am not very familiar with maintaining a machine on this harsh environment.

Also, they are complaining that the chemical fume is "eating" exposed conductors. Here I do not have picture so I will try my best to elaborately decribe it. They have a couple of "spliced" wiring insulated by electrical tape/ electrical connector. Just recently they've found out that fume penetrates the tape causing breakage on the conductors. It was reported that this has always been the case, and they are asking for a permanent solution on this matter.

Is there any connector I can use to prevent breakage on the conductors?


leitmotif said:
Pictures are worth 10,000 words. Yours saved you bunches of typing.

ACRONYM ALARM -- NEC stands for National Electric Code.

Dan Bentler
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:D:D


Erika
 
Ripley

Given that this is a plating operation I know of nothing that will give permanent immunity to acid vapors. So "acid corrosion" is a fact of life that will not go away and will cause continuing maintenance. The most recently installed plating shop I have seen used fiberglass grating for decking and where they could structural members of fiberglass.

The No Alox has given me good service for 15 or 20 years. It is a single application when you assemble or crimp the connectors.

For best service of conductor splices I would recommend Western Union splice which is then soldered. Then insulate and encapsulate with Scotch Cast.

The time and money not spent doing PMs in this operation will be spent multifold in breakdown maintenance. Plating operations are maintence intensive. If these guys dream of maintenance free they really should stop smoking opium.

Dan Bentler
 
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Just recently they've found out that fume penetrates the tape causing breakage on the conductors. It was reported that this has always been the case, and they are asking for a permanent solution on this matter.
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The only permanent solution would be to sell the plant to someone that knows about preventive maintenance. o_O

Sarcasm aside, you could recommend a waterproof splice connector. That would be better than tape at preventing corrosion. These type of splices are used to connect underground direct-burial cables. Many use a plastic sleeve where, after crimping the connector onto the wires, you fill the sleeve with waterproof epoxy compound, making a completely sealed connection. I would not call it "permanent" but as close to it as you will get in this world. Make sure the cable insulation is cleaned of all corrosion products, grease, and dirt, or the waterproof splice will not seal very well. The splice will only be as good as the original cable insulation. When the old insulation cracks or leaks, corrosion will still happen inside the splice. I bet the old cable does not have corrosive-resistant insulation, nor rated for use in that environment. Here are some pictures of waterproof splice kits.
http://www.google.com/search?q=wate...fOoOE8ATz6YCABw&ved=0CGsQsAQ&biw=1024&bih=615

If they insist on using tape, at least recommend a corrosive-resistant type, such as Scotchrap 50:
http://www.cablejoints.co.uk/sub-pr...cal-tapes/scotch-rap-corrsion-protection-tape
 
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Lancie1 said:
The only permanent solution would be to sell the plant to someone that knows about preventive maintenance. o_O
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🍻

Lancie1 said:
Sarcasm aside, you could recommend a waterproof splice connector. That would be better than tape at preventing corrosion. These type of splices are used to connect underground direct-burial cables. Many use a plastic sleeve where, after crimping the connector onto the wires, you fill the sleeve with waterproof epoxy compound, making a completely sealed connection. I would not call it "permanent" but as close to it as you will get in this world. Make sure the cable insulation is cleaned of all corrosion products, grease, and dirt, or the waterproof splice will not seal very well.
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We are looking at this option as well. But I think your previous suggestion is better:)

Thank you for sharing your time with a newbie like me.
:site:
 
...although they are contained in a chemical resistant box, the box has no cover.
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That the cover was removed and considered of such little value that it was never reinstalled says a lot about the attitude and knowledge at this place. Educating the customer is often the hardest job.
 
On our main enclosure, we blow air into the enclosures to slightly pressurize them. We dye yarn here and the dyes are acid based. The vapors tend to coat everything around it after awhile. I talked to their maintainence department and the component failure went from 1 failure a month to maybe 1 a year. Nothing special about the air, it is blown over through PVC piping from elsewhere in the plant. I am using servos and recently heard about a fitting that's fits between the cable plug and it's motor connection. It allows you to inject 1- 5 psi in to motor and pressurize it to keep vapors from entering.
 
Mark Buskell said:
On our main enclosure, we blow air into the enclosures to slightly pressurize them. We dye yarn here and the dyes are acid based. The vapors tend to coat everything around it after awhile. I talked to their maintainence department and the component failure went from 1 failure a month to maybe 1 a year. Nothing special about the air, it is blown over through PVC piping from elsewhere in the plant. I am using servos and recently heard about a fitting that's fits between the cable plug and it's motor connection. It allows you to inject 1- 5 psi in to motor and pressurize it to keep vapors from entering.
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Hmm compressed air into cabinets - had not thought of that. Should work I think. Just goes to show one guy does not have all solutions

Dan Bentler
 
Mark Buskell said:
On our main enclosure, we blow air into the enclosures to slightly pressurize them. We dye yarn here and the dyes are acid based. The vapors tend to coat everything around it after awhile. I talked to their maintainence department and the component failure went from 1 failure a month to maybe 1 a year. Nothing special about the air, it is blown over through PVC piping from elsewhere in the plant. I am using servos and recently heard about a fitting that's fits between the cable plug and it's motor connection. It allows you to inject 1- 5 psi in to motor and pressurize it to keep vapors from entering.
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I second this type of idea. Blow clean low pressure air into the enclousre and conduit and have exhasut taps to allow for flow.
 
You have to be careful with compressed air. Even a very small PSI equates to some large forces if you consider the surface area of the inside of an enclosure. You're better to to have a blower.
 
Mark Buskell said:
On our main enclosure, we blow air into the enclosures to slightly pressurize them. We dye yarn here and the dyes are acid based. The vapors tend to coat everything around it after awhile. I talked to their maintainence department and the component failure went from 1 failure a month to maybe 1 a year. Nothing special about the air, it is blown over through PVC piping from elsewhere in the plant. I am using servos and recently heard about a fitting that's fits between the cable plug and it's motor connection. It allows you to inject 1- 5 psi in to motor and pressurize it to keep vapors from entering.
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Greatly appreciate it.
 
One note of caution re compressed air. Water vapor will condense in the air lines and will accumulate in low spots. Even with good driers this will still happen. Make sure you have water / oil separators before each cabinet lest the cure is worse than the disease.

Dan Bentler
 
leitmotif said:
One note of caution re compressed air. Water vapor will condense in the air lines and will accumulate in low spots. Even with good driers this will still happen. Make sure you have water / oil separators before each cabinet lest the cure is worse than the disease.

Dan Bentler
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Great point, and all the other fun substances that often end up in compressed air as well.
 
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