Ready for use:
What do you usually put in the screw nut so it can't loosen? I'm afraid all purpose general glue (alongside breaker in picture) may not stop it. If I put epoxy. It may be unremovable and can't screw it if needed in the future. Would a single mighty bond glue compound stop it (but this is supposed to be put between two materials). Any other idea? It's 1/8 in size and couldn't find any tiny locknut for it.
After teardown of the Westinghouse Breaker and handling it for a day at office during break removing the parts and putting them back again and again. It gave me courage to finally initiate teardown of the Siemens Load Center main circuit breaker (especially when no one can offer any clue what could be wrong with it and no teardown of it anywhere in the net).
I spent more than an hour in the evening removing the 4 mini-bolts manually so in case the defective is not mechanical or serious, I could still use it (the casing is not glued and there are only the 4 mini pins holding all of them together). So it's not technically a teardown but repair. I found out the problem. First youtube video of the internal parts and illustrations:
It's just a typical circuit breaker internal components. Nothing unique. The source of the problem why you need to push it a bit more for the latching to be made is due to housing dimension tolerance. Compared to other breakers where the latching is made 75%. In the Siemens. It is 90% before the spring hatches it to make full contact. So slight housing misalignment need you to push it a bit more (and it is only in one of the breaker (remember it is two pole so has 2 separate unit). No problems with the bi-metallic strips or catch mechanism.
I assembled it back and will put it in service since nothing wrong with it. I checked dozen times the mechanical parts and orientation is same as original (with many photos taken in different stages of the teardown. My question is. What do you call this tiny pin-bolt? I can replace it with 4 thin long screws locking the breaker in place (by gluing the 4 nuts so they won't loosen or even epoxy it, isn't it?) What did you do?
old message:
I just made teardown of a Westinghouse breaker and became so familiar with all the mechanisms I can take all things apart and assemble the inside.
Using the Westinghouse breaker teardown as sample. I couldn't extrapolate what is wrong with the Siemens.
I couldn't return the item. It costs $45. And a new one cost $85 shipped. So I need to know if what could possibly be wrong with the Siemens. Doesn't it use a standard latching mechanism? Any illustration of what mechanism it could be using?
Is this really defective?
In this even newer video.
I can consistently make it stay latched by pushing it after it is in the on position. Listen to the "click" after I turned it on (in first and second attempt, increase the volume of your speaker so you can obviously hear the click). In third attempt, I didn't push it so it returned. At 4th try I pushed it with a click and it stayed latched. Can't you consider it as tolerance? What mechanism inside the breaker is exactly involved, any idea?
earlier update.
I found out you need to slightly push the lever in so it can stay in on position. See this youtube video:
In the first and second attempt. I didn't push the lever so it returns to OFF position. In the third attempt. I need to push it gently down so it can be in On position. Is this normal, or is the subpanel breaker slightly defective? I have handled many other breakers and it doesn't have this behavior.
original post.
I bought a new subpanel, and the main breaker is already defective (brand Siemens). It can't be switched open (even isolated on piece of paper like in the picture). It returned to close position immediately. Usually what are the parts inside that get broken easily even without any use? Anyone has tear down such to see what is defective inside?
Best Answer
Send the breaker back (as a warranty return), get some main lugs instead
This breaker is clearly NFG, and thus needs to be sent back under Siemens' warranty (it's a 1-year warranty, but that should do the trick for an infant mortal like this one). While you're at it, what you want for a subpanel sitting right next to the main isn't a main breaker, but a set of main lugs instead -- the correct part for your panel will be a Siemens ECMLK125 kit.
This is because the busbars on such a panel are an extension of the feeder, so they are protected by the feeder breaker as the feeder tap rules aren't in play here, and the upstream and downstream panels are in the same building, so the downstream panel does not need to provide a master shutoff switch for power to its circuits.