I don’t know if this fits here cause I’m not tech support, but I hope it’s close enough. I’m an electrical engineer that works field support for industrial furnaces. I have a lot of stories of stupid maintenance personnel, but this is my favorite. If you guys feel this stuff can fit here, I may share more.

So we receive a call from a client. They are having the most common problem with our furnace. They have a ground problem. Usually this means the aluminum or iron has gone through the lining so we start there. We instruct the maintenance personnel to check the lining of the furnace for penetrations and if it’s not that, remove the yokes one by one to inspect that. We tell them to call us back after.

Couple hours later the client calls us back.

Client: It’s not in the furnace.

Me: Well we don’t know that for sure yet. It still can be. There’s one more step.

Client: It’s not.

Me: Well we can prove it by removing one side of the bus.

Client: The what?

Me: The bus bars.

Client: What?

Internal sigh. Apparently this guy has little training on our units despite having a contract for training every 6 months.

Me: The two metal tubes that conduct the electricity from the power supply to the furnace.

Client: Oh. Yeah. How do I do that again?

Trigger face palm.

Me: Unbolt it above the capacitor cabinet and add insulation paper between the bars.

Client: That sounds like a pain.

Me in my best salesman voice: Well if you want we can retrofit an isolation switch in there at some point, which will ease the troubleshooting in the future.

He grumbles.

Me: But for now, this is what you need to do. Call me back after.

I hear back from the client the next morning.

Client: It’s still grounding out.

Me: Bus disconnected?

Client: Yes.

Me: Ok that means we have isolated the problem to the power supp-

Client: We need a field service guy.

Me: There’s one more step-

Client: Just get here.

Me: He’ll just sit on his butt the first day while he makes you go through the procedure.

Client: I’ve got a P.O. just get out here.

Surprised, and a little frustrated, I go to my boss with the P.O. so he can pick out the guy who’s gonna go. It’s Friday, so the client won’t be able to get parts, and my boss sends the weekend quote, trying to talk him into finishing the procedure himself. He has none of it. Boss tells me I’m going since I started it. Reluctantly, I book my flight to Kentucky.

I show up the next day on site, ready to get to work. I meet the guy I was on the phone with and ask him if he can partner me up with an electrician since its an electrical issue. To which he replies, “I am an electrician.”

I contain my shock, and proceed to the furnace.

Me: There’s a slug in there.

Client: Yeah, you took too long. It hardened up.

Me: How can you tell if there’s penetrations with a full furnace?

Client: The metals all there! I can’t see any penetrations, can you?

I sigh. This is bad, as remelting the furnace like that will cause the metal to expand and damage the lining. I explain to him this and despite his concerns of the expense, we move on. I now obviously know he did nothing I had asked him to, but with a full furnace I can’t start there.

We go downstairs, and rather obvious by now, the bus is intact.

Me: You said you disconnected the bus.

Client: Well, it’s water cooled and I didn’t want to get things wet.

Me: That’s why you disconnect it between the cooled lines.

Client: What?

Me: I need you to disconnect it here.

I point at a section of the bus where the water lines change out. He tries to get me to do it, but I can’t fly around with wrenches that big in my box, so he reluctantly does it himself. Afterwards we turn it on and luckily the ground stayed. It’s in the power supply, which means we can find it! Unfortunately the ground meter is up two flights of steps, so checking it every few minutes would be a pain.

I ask if he has a spare ground meter, and luckily he does. He runs and gets it and it’s our 0-10V style meter. Awesome. We head downstairs.

Me: Ok. Next step is checking the capacitors.

Client: Oh. Wait. How do you check a cap?

Me: Well you have to pull it out of circuit one by one and turn it on again. That’s why I had you get the spare meter. I need you to wire it up in parallel with the one upstairs.

Client: parallel?

Me: Parallel.

Client: How?

What I wanted to say was “Are you sure you are an electrician?”

I proceeded to explain to the client what the difference between series and parallel was, and then we found a bad capacitor. We disconnected the capacitor from the circuit and he was able to run again.

On my way out of the plant, I informed him that while it’s safe to run without one or two capacitors in circuit, it won’t be the ideal resonance frequency and prevent him from going to full power. It would reduce his efficiency. That he really needed to buy a new one if he wanted to run at full power. He said he understood and sent me on my way.

Not a month later, I get a call from my boss. Apparently he was complaining cause his 1MW furnace was only running at 937KW and doesn’t know why.

He has yet to replace the bad capacitor.