lessons learned...

[zeeprogrammer]

I'm not sure where to put this...no problem if some one wants to move it...even the round filing cabinet is okay...

One of the things I hope to do when I finish my current project is to post a 'lessons learned'. Its something we do at work when we finish a project and something we read before we start a project. It both helps to educate and to prevent our going down an erroneous path trod by someone before.

Just putting it out there...


'course...I'll have a lot to say...most of you will have far less...

 

[rleete]

It may seem like simple, obvious stuff to old hands, but to us new guys it's important. I also started a document as I was building (with the intention of posting it later) to help me remember some of the things I learned along the way. None of it earth shaking news, but simple "don't forget to's" and such. I think typing it out also helps to reinforce those lessons.

Looking forward to seeing your list, and compare it to mine.

 

[itowbig]

good idea there. trying to remember it all can be hard to do. wittling down on paper or storing in ye old computer by each project is good. (note to self must use shop computer more now)
all these good ideas . what a great place

 

[zeeprogrammer]

Thanks.

Just some more thoughts...

Don't forget the 'why'. That's something that bites us at work all the time. Some idea that says "do it this way" or "don't do that" and you're left wondering why. Worse, over time the reasons can change and hence the rule too.

On that note...just as important...are the 'what not to do' learnings.

I'll be very interested in seeing what comes out of this.

 

[SignalFailure]

Well I nearly made a silly mistake tonight...

I'd silver soldered the brass mounting ring on to my copper chimney tube and needed to solder the brass top bit on the, er, top!

So I came up with this great jig and felt very clever - brass base with 6mm hole, chimney, brass top with conical centring device, 6mm studding run through the whole, washers and nuts holding it all together.

I'd just started to play the flame over the top of the assembly when I realised that I'd created a nice little bomb and would probably require a change of underwear if I continued.

For anyone not used to soldering, it's best to avoid sealing up any joint that would creating a pressure vessel ... I seem to recall Pressure = Volume x Temperature from school so unintentionally increasing the temperature in a fixed volume is not rrecommended

Not so much a lesson learned as a silly mistake avoided - like leaving in the chuck key

 

[zeeprogrammer]

Very glad you didn't get hurt!
Thanks for the post.

 

[Kermit]

I have one that applies to what we do around here.

NEVER trust the electric outlets are wired correctly until you have CHECKED them.

Getting the Poop shocked out of you will help you remember this one. Just set the meter to measure AC voltage and touch one lead to something grounded and the other to the metal of the machine you plugged in. You should never see more than 1 or 2 volts.

I've found several machines ready to shock someone by checking this. This mostly happens when you have equipment plugged into different outlets. If the hot and neutral get swapped everything will still work, most of the time, but if physical human contact is made between the metal of that machine and ground or another machine plugged into a socket wired correctly. It will shock you and if you are hot and sweaty and get pinched between the two it can kill you.

Check each piece of equipment where it is and check it again if its moved. They can be wired in reverse in the machine or in the outlet. Most of them remain this way for a long time before the situation is right for the error to be "discovered".

Harbor Freight had some really good meters on for 4.99 not long ago. I bought two(never have enough it seems).


Shock the meter, not the monkey;
Kermit

 

[zeeprogrammer]

Always listen to the inner voice.

I was replacing the dishwasher.
Had my left hand on the copper pipe.
See where this is going?
I felt a vibration, buzz, something on my leg.
Thought it was the dog and looked behind me.
No dog. Leg was up against the stove.
Hm...
Decided to give the stove a little slap.
The inner voice said..."nooooo...don't do that!".
But it was too late.
It turned out the stove had a short.
Took the jolt from right hand to left.

My wife was standing behind me.

She said..."A body isn't meant to move like that".

I said..."I know dear. Thank you."

...............

I was working on the kid's bathroom light.
Wife came from the adjoining bathroom asking why the light was flickering in our bathroom.
I said it shouldn't be and went to grab the loose wire in the kid's bathroom.
The inner voice said..."nooooooo...don't do that".
But it was too late.

She said..."I hadn't heard that one before."

I said..."I hope you never hear it again."

..............

I got more but I think I've demonstrated enough stupidity.
It doesn't help that I'm an electrical engineer.

 

[jwsvandr]

Speaking of electrical.... Helped a friend replace his ceiling fan a couple of years ago. We had the switch shut off and things were going well thill I accidentily touched two wires and a whole bunch of sparks showed up. Forgot they use a separate hot feed so you can run the fan with the lights off... I now check all the wires before touching them

 

[AlanHaisley]

I have one that applies to what we do around here.

NEVER trust the electric outlets are wired correctly until you have CHECKED them.

Getting the Poop shocked out of you will help you remember this one. Just set the meter to measure AC voltage and touch one lead to something grounded and the other to the metal of the machine you plugged in. You should never see more than 1 or 2 volts.

In the US, some hardware stores, as well as places like Home Depot or Lowes, carry an outlet checker. This is a simple little device that has three neon bulbs (and I assume some rectifiers although I have never opened one up.) Plugged into a normal three wire US outlet, the various lights will show if the circuit is live and if it is wired correctly.

There may be UK, Euro, and Oz equivalents of this little tool. If so, get one. Here they are only a few bucks and well worth it. th_rulze

These won't work for light sockets, which are just as great a hazard. For light sockets, as well as metallic fixtures and appliances, get a little neon test probe. The best for this are the ones that look like a little screwdriver or tiny icepick. It turns out that if one probe is left to float while the other is used to probe, if the probed surface is live the bulb will light at about half brightness. Use these on the supposed grounded (the threaded portion) part of a light socket to see if it is wired backward. Use them on the appliances and such to see if there is a leakage voltage, indicating a broken wire or other short circuit.

Alan

 

[dparker]

Hello All: I also have a few of my own stories concerning electricity. I apologize if this is too long but electricity and I mix about like oil and water.

About 1960 I was rewiring 3 phase motors in our family business (cannery) up on a 14 ft ladder. I started unhooking the wires and got a tingle, even though I thought I had turned the breaker off. So its off to the electrical room across the building. Tried it again and still got a tingle, back to the Electrical room , on the third time I went back and turned off every breaker I could find and climbed the ladder and took the linemans pliers and cut the wire. Wow----4th of July early that year! I sort of slid down the ladder and when I hit the floor my knees would not hold me up and I just sat right down on the floor. I looked at the pliers and the cutting edge was no longer there, sat there looking at that for a while until my knees would hold me up. Went up to the front office and into my Dad's office and showed him the pliers and asked where the breaker was to cut the power to that motor was, after he quit laughing he said "Its not on a breaker it's on fuses". Finally got the wire moved and the motor running in another spot.

A few days later I was rewiring 3 phase motors that run the sorting belts when we rearranged the sorting room. I shut off the appropriate breaker (checked it this time) and went to work and set my tools right up on the belt where they would be handy. I was just about done and hooking up the last wire and a few sparks and all my tools traveled across the room and dumped on the floor. One of the cowboys working for us couldn't get the grinder to work in the shop so he started turning on all the breakers that were off.

I went to work in the early 70's at a pump company here in Portland OR, I soon started to run the Test lab and do most all of the electric work and welding along with the fabrication of test stands and doing the certified pump tests and R/D on new products.
I did a little better when I was running the Test Lab for the pump company and we were made to "lock things out" when working with electricity by OSHA, (don't really like them but they did probably save my life if the truth were to be known) I had far fewer electrifying experiences but still managed to get hit with 480 volts every once in a while.

I must admit I was VERY careful when we were running pumps on 4160 volts!
don