MIDWEST was asked how we can tell if a bus plug has been water damaged. What if a brand new bus plug is exposed to water, say rain. How can we tell after it has already dried off? If it’s new, how would MIDWEST even know it was exposed to rain or water? The answer goes to the heart of why MIDWEST fully reconditions bus plugs. If a bus plug has been exposed to water, we would know as soon as we disassemble it for reconditioning. The old or new bus plug hardware, nuts and bolts and washers, would have some rust. The exposed surfaces of bolt holes would have rust at the edges. This is more obvious than you might think. In addition, between the inside of the new bus plug enclosure and attached interior parts, we find dust that has the visual pattern of water exposure. Like spilling water on a surface that had just a little dust on it. After the water evaporates, you can still see the pattern of the water exposure on the surface. Usually all this is pretty obvious to the engineering technician doing the work, if they are actually reconditioning the replacement bus plugs. But, if a company is just giving it a shoe shine, meaning a little inside cleaning with a little outside painting, they may never detect the water damage. Even an insulation resistance test pole to pole and pole to ground may not reveal the damage. But it is there and it shortens the reliable life expectancy of the bus plug. Rust especially is insidious when it starts at support hardware. MIDWEST’s best suggestion is to buy fully reconditioned equipment if you are buying obsolete bus plugs, used bus plugs, or new surplus bus plugs. This is true whether buying Square D bus plugs, Siemens bus plugs, ITE bus plugs or any other manufacturer’s product.
Categories: General Bus Plug Information, Questions Asked By Our Customers Tags: Bus Plug Parts, Fully Reconditioned Bus Plugs, Insulation Resistance Test, ITE Bus Plugs, new bus plugs, New Surplus Bus Plugs, obsolete bus plugs, old bus plugs, Replacement Bus Plugs, Siemens Bus Plugs, square d bus plugs, used bus plugs, Water Damaged Bus Plugs
MIDWEST’s Switchgear Shop received an unusual request for blue Square D bus plugs and black General Electric bus plugs. Plus, we were asked if we could paint ITE and Cutler Hammer bus plugs other colors and if we could put a unique label on each bus plug. Of course the answer was yes, but this was different. We have reconditioned Westinghouse bus plugs and Cutler Hammer Bus Plugs that were already painted black and we had to repaint them gray. We had some Square D bus plugs and General Electric Bus Plugs that were a 1950’s kitchen cream color and looked like they had been repainted every ten years. But this was the first time that a customer requested a specific color, other than the manufacturer’s original color, which is usually gray.
They had a lot of 30 amp and 60 amp bus plugs. Quite a few 100 amp bus plugs and a couple 200 amp bus plugs and one large 400 amp bus plug. But what was really unusual was their reason for the color coding and labeling. It appears that, in some states, bus duct and bus plugs that are used only on a specific manufacturing machine or production process, are exempt from state tax. If they buy replacement bus plugs or have service on the existing bus plugs, the replacements and service is non taxable. If the bus plugs or bus duct are used on something other than a specific manufacturing machine or process, service and equipment is taxable. They wanted the bus plugs for a specific process to be all the same color. They also wanted the bus plugs to be painted the same color as the bus duct and to be labeled for the specific manufacturing machine or process. We are not state tax experts, but, as they explained it, it seemed to make sense.
Categories: Questions Asked By Our Customers Tags: 100 Amp Bus Plugs, 200 Amp. 400 Amp, 30 Amp Bus Plugs, 60 Amp Bus Plugs, bus duct, Cutler Hammer Bus Plugs, General Electric Bus Plugs, ITE Bus Plugs, Painted Bus Plugs, reconditioned bus plugs, Replacement Bus Plugs, square d bus plugs, Westinghouse Bus Plugs
A foundry called MIDWEST for another replacement bus plug. They said this was the third one he bought from us in the last two years. He thought it was strange that he suddenly had so many failures and had to call us for replacement bus plugs. The man that called was a foundry maintenance mechanic. These men are the salt of the earth. They can fix just about anything with just about nothing. So we pay pretty good attention to their problems. In this case he complained that their bus plugs must be junk because they were suddenly having so many failures. He was sure something was wrong right from the manufacturer. They never had any problems and suddenly they were all failing. We checked our records and all the replacement bus plugs were for old equipment manufactured in the 1960s. They actually had very good luck with their bus plugs until the last couple years.
We had a little confirmation bias going. The maintenance mechanic thought there must be something wrong with the bus plugs. Why? Well, because the bus plugs were failing, so there had to be something wrong with them. Makes sense, kind of. The reality was that the equipment was getting very old, it was dirty, was seldom exercised, and therefore was mechanically less reliable. We explained that electrical equipment ages and as it gets older the frequency of failure will increase, sometimes rapidly, depending on the condition. We see a very low failure rate for bus plugs in a facility that isn’t very old and is clean. For similar facilities that are much older or much dirtier, the failure rate is higher, and increases as the facilities age. But all this is trumped by the condition of the facility and the load on the bus duct and bus plugs. In a foundry, all bets may be off. In a foundry, when equipment suddenly starts to fail, the sudden increase in failure rate is usually due to condition and not merely age. The failures are a warning that it is time for cleaning and maintenance.
MIDWEST’s Switchgear Shop was asked if they had a simple video of reconditioning a bus plug. The answer was, “Not yet, but give us a couple weeks.” They figured the customer asked, so they had the green light to make a video. This was truly a collaboration of Techies. Three weeks later they had two hours of video of everything to do with reconditioning an old used bus plug. They figured they had it all covered, disassembly, stripping, cleaning, replacing hardware, painting, reassembly, labeling, testing, and final QC checkout. Everyone was pleased until they were given the task of reducing their famous bus plug video from 2 hours to 5 minutes. Ouch! This seemed impossible to them. There was a lot of work, and therefore video, to reconditioning old used and sometimes obsolete bus plugs. The problem was solved by having just one person work on the editing.
In the end, everyone was pleased until Engineering viewed the video and went crazy because all the final testing and QC was edited out. The video is now back for re-editing. You can’t please everyone, especially fanatics.
A maintenance electrician asked MIDWEST what he should do about a 200 amp Square D Bus Plug that was sagging several inches down from the overhead bus duct. He said the conduit from the bus plug was poorly supported and was pulling it down. His supervisor wanted him to try and fix it on the fly. That made him really uncomfortable and he wanted MIDWEST’s recommendations.
This problem has nothing to do with the manufacturer. It could have been a General Electric or Westinghouse bus plug just as easy. The problem is the installation, not the equipment. We have seen this all too often when doing Infrared Scans of overhead bus duct and bus plugs.
First of all we recommended in the strongest terms that no one try to fix this problem without shutting the power off. We mean shut off the power to the bus duct, not just shut off the bus plug. The connection of the disconnect fingers on the back of the bus plug to the bus duct is the most vulnerable to failure and will do the most damage if it faults while the system is on. Besides possibly getting someone seriously injured or killed, you could lose a section of bus duct and have a protracted power outage. The danger to the maintenance electrician is too great to even consider adjusting the bus plug energized.
As far as just leaving well enough alone, we don’t buy that either. This is what MIDWEST calls an incipient failure, a failure that will happen sometime in the future. When, we are not sure. But it will certainly happen. Our experience is these things happen on July 4th or Thanksgiving Day. That’s just the way things seem to go sometimes.
The danger of catastrophic damage to equipment and, more important, the danger to a maintenance electrician trying to adjust the bus plug while it is hot, is just too great. We would categorize the idea of doing this hot as “Crazy.” Besides, you are not allowed to do something that has the danger of serious injury or death.
Turn all the power off and properly plumb and support the bus plug. We also recommend removing the bus plug and checking it for damage, before reinstalling it correctly. Do it right and no one gets hurt, always a good idea.
We were asked by a maintenance supervisor if it made sense to infrared scan the bus duct in his manufacturing plant. He suggested it was a waste of time because the conductors in his bus duct were totally enclosed. MIDWEST hears this question a lot. He had a mixture of old bus duct and bus plugs and new. He was especially concerned with the new bus duct and bus plugs because he was adding more and more load and they had a lot of trouble adding some of the new bus plugs because of their location above production machines.
As we have said many times, infrared scanning is the best service possible for finding current related problems in bus duct and attached bus plugs. The Infrared Scanner is so sensitive, it can find warm bus splices and overheating bus plug connections long before they turn into a full blown critical hot connection or arcing failure. This is true for obsolete bus plugs and duct, even when it has been operating for decades without any problem. The real challenge with infrared scanning is when the bus is over production equipment and in very had to see locations. Still, for an experienced Thermographer, these challenges are easily overcome.
So, whether vented or enclosed, feeder or plug in bus duct, Infrared Scanning is the least expensive and most useful maintenance service available.
We recently moved to an existing facility wired with older Bus Duct and are having trouble finding Bus Plugs, new or used in the sizes we need to feed our equipment. Should we change out the duct to a new brand where the plugs are easier to find?
No, there may be a more cost effective solution.
Assuming you moved to a building where the volts match and the building can supply all of the amperes your machines need.
We have seen where new occupants have decided their best route is to rip out the bus duct and use pipe and wire to connect their machines. This works out well when there are fewer machines to serve or when even a few are very large. These machines might otherwise require a bus plug that is rated at or near the capacity of the entire duct. Other times the location of a machine in relation to the bus plug is less direct than extending from a spare position in the buildings main distribution switchboard or panel board.
After you have considered how long you will use this facility you could look at relocating the existing duct to better suit your needs or you could uses tap boxes or a large bus plug, some pipe and wire and connect to additional lengths of ‘easy to find’ duct and Bus Plugs. However, pipe and wire direct from the Main Distribution to you machine sometimes can be your best option.
We received a question from Fred…Hi from Texas. I have a problem and I’m looking for a blogger to help me, if possible. We hit a 200 amp bus plug with a pallet being lifted by our fork truck. Nothing happened, but it is crooked and I’m worried, because my experience is this stuff will go bad on Memorial Day, the 4th of July. Just the way things seem to work out. To check the damage to the bus plug we have to turn a line off and that can only be done on a weekend and that costs overtime, which is invisible these days. Anybody out there with real experience that can tell me whether or not I should check this out. I don’t know how bus plugs are made or how they attach the main line. If I do shut the line down, what should I look for? What would typically go wrong if you hit one of these things and it moves about 2 inches? The pipe coming out the top looks okay, but I’m really concerned by how this thing connects to the hanging metal enclosure that runs the length of the room. Anybody been through this? Any ammo to take to my supervisor to justify the work? And what should I look for. Any help would be appreciated. Thanks, Fred Jenson
Answer: Fred, here are the easy answers. First, you need to check this out soon. The main bus duct that this bus plug connects to, could fail with a catastrophic fault that could destroy the main bus duct and the bus plug and possibly get someone hurt. Recommend to check it out at your first opportunity. Do you have a spare? Many electrical problems are actually just mechanical. So shut her down, Lock it out, Tag it out, Check voltage and then have your best electrician and mechanic investigate the damage. Take a good look at the connections between the old bus plug and the bus duct. Be safe Walt