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1

Last thing you want is a dodgy circuit breaker. I suggest that you replace it so when and if you ever have need for that breaker to protect a circuit you can depend upon it to work properly. I got the impression from reading your posting that you are using this circuit breaker as a regular switching function. Be aware that some breakers are not intended to ...


0

I had a similar problem in my basement where all the outlets were dead except the two that control each garage door openers. I made a jumper cable with two male ends and fused the hot line with a 10 amp automotive fuse. You plug one end of the jumper into the door opener plug and the other end into one of the dead outlets. Now all the rest of the plugs on ...


2

This sounds like a bad connection upstream of the panel. No load, you get voltage - apply a load, voltage goes away. Try turning off all the breakers on the affected bus, with it connected. Does voltage return? Try (since you seem comfortable handling the feed wires - right, you do say sub-panel) marking the feeds and see if the problem follows the wire, ...


0

If all the breakers on every other row go out, you lost one of your phases. That's not as bad as losing a neutral, in which case each 120V leg can go as high as 240V, blowing stuff up and starting fires. All that to say, if it proves to be a wire connection problem, check your neutral too! If both breakers in a single row go out, you may have a burned up ...


0

Are you sure nothing else is plugged into that circuit? It may be just enough for the normal load, not enough when one more thing is turned on...


3

If space permits, you could also run an additional isolated neutral buss bar (connected to the existing neutral bar, and isolated from the box/ground.) My main panel has 3 interconnected ground buss bars (left, top, right - power entry at bottom) to keep it convenient. Small change in the grand scheme of things. Use adequately sized wire for the ...


0

My guess about the wire nuts is that a load center is not a junction box. My inspector passed me with the same issue.


6

The AFCI wire needs to connect to the neutral bus. Put it on the other side, or add on to the length of the wire with a wirenut.


0

Could be something as simple as a short between the 100A breaker and the subpanel. Have you inspected the entire length of the wire for e.g. signs of rodents chewing on insulation? Also, your photo is unreadable and all I can tell is that you have four breakers, one of which is single-pole and I'm not clear about the others. What are the ratings and phase ...


5

It could have to do with the trip curves of the breakers, and/or the ambient temperature differences between panel locations. Trip Curve For example, let's say all the circuits on Phase A are drawing 3 times the rated current. The trip curve for these breakers, say they will trip between 10 and 30 seconds at 3 times current. So the total current on Phase ...


2

Breakers trip on overload or short circuits. A dead short could easily trip a main breaker.


5

Manually flipping a breaker, especially without a significant active load, should never melt a breaker. A melted breaker indicates a large heat build-up. This could be a defective breaker but is more likely a bad connection, producing resistance, which heats up under normal load. This could be an insufficiently tightened screw connection to the hot wire, ...


3

Disregard the arm-waving guesses at how much power the PC "might" draw, and buy a Kill-a-Watt. Bonus points if you get a better type of power monitor that can data-log. The Kill-a-Watt can also tell you a lot about power factor. Low power factor means it is causing interesting side-effects that masquerade as drawing more current than you actually are on ...


3

Based on some details that were revealed in comments, I think I should post this as an answer. Your comment said: Using 4 PSUs (450 each) on each 20 A circuit. 80% is 1920 and I'm using 1800. I thought I had room to spare. Apparently not. There is an 80% circuit breaker derating rule: you are only supposed to draw 80% of the breaker's rated current ...


5

EE here. PSUs have a non-linear relationship between current draw and voltage. Your calculations assume that the PSUs are purely resistive loads, and they are not. Assuming the circuit is not also oversubscribed, the circuit breaker can be fooled in this situation. A circuit breaker exists to protect the wiring from overheating and starting a fire. It is ...


23

If your device is drawing too much power, and is causing the breaker to trip. It means the device is too large for the circuit, and the breaker is doing the job it was designed to do. Making an "automatic breaker turner on-er" is not likely the best solution. There's two possibilities for why you'd trip the thermal protection of a circuit breaker. If the ...


18

Sounds like there are two options. Option one is to replace the existing breaker because you think its defective. This option is good if you know that you're not using enough power to trip the breaker so something else must be going on. However, it doesn't sound like this is the case. Option two is to run a new dedicated circuit to the room to handle the ...



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