After a minute running, dryer trips main breaker outside the house, but no internal breakers

Question

I recently solved (sort of?) an issue regarding my washer & dryer not getting power. I consider that issue solved, but now I have a new one, possibly what caused the problem before. Now that I have power to my washer & dryer, I did a small test load. Washer did fine, but the dryer tripped the main breaker outside (100A), but none inside. This didn't even happen when I started the dryer, but after 1-3 minutes (closer to 1 I think) it would trip. I have tested that 4 times now and when I have the dryer off, nothing trips - but a couple minutes after starting the dryer, the whole house goes down.

The breaker panel shows no tripped breakers (all firmly on the ON side - I have turned them all off/on just in case as well). The inside main breaker is fine too. The outside breaker however is clearly tripped. I clear it and turn it back on and everything is fine. Both inside and outside are 100A. Dryer is a 2-pole 30A breaker, which I just replaced today after noticing this new problem.

Previous post I had on my initial issue is here. There are lots of pictures of my breaker and some other backstory on this problem.

Edit: Damn. The outside breaker just tripped with the dryer breaker off.

Things I have on/plugged in/on: TV, router/modem, swamp cooler, fridge, water cooler/purifier, water heater, a few lights and a few things plugged in (biggest is my laptop here).

It is in the upper 90s here... could that be affecting something?

7:10pm (15 mins ago) happened again. Did some deduction... When it tripped then, W&D breakers were off. I left everything on the inside on and went to try and reset the outside, but it didn't reset. Went back inside and picked the breakers with only numeric labels (1,2,3,4) and turned those off, and then the outside breaker would finally reset. So by my logic, its one of these four. Next time I'm going to turn these off one at a time when trying to reset the breaker, hopefully that will narrow it down more.

Answer 1

The problem with mine was that the dryer started causing an existing loose wiring connection to spark and overheat at the panel, were it screws into the dryer breaker. The problem wasn't with the dryer or the breaker per se, but the dryer is electric so it drew so much current that it revealed the loose connection and exacerbated it, by the extreme heat and resulting oxidation of the copper. I think the heat may have been what tripped the breaker, because my Fluke tool only saw a max current draw of about 20-21A from the dryer. Find a safe way to check the main breaker's wiring connections and look for evidence of sparks and heat. Might be able to have a professional cut back the wire to a fresh spot and redo the connection, but after that kind of damage, it would make sense to spend another 10-20 dollars on a new breaker. That is, assuming my problem applies to the reader.

Answer 2

It seems to me, after reading all the stuff in your first question and on here that the problem is inside your cloths dryer. There is a good chance that some part of the heater coil is becoming shorted out and causing huge amounts of current to flow when the coil becomes hot.

The probable reason that it is the main breaker that trips is due to that breaker being the most sensitive to the sudden current surge short that occurs in the dryer. It may be an indication that that main breaker needs replacement but before even going down that road it is time to unplug the dryer and do a through investigation of its innards, particularly its heater unit and the wiring thereof.

Answer 3

Sounds like it's tripping out on total load of the house, not specifically from the dryer. The fact that the problem started after replacing the dryer is coincidental. The dryer contributed to the problem, but really it is the total of current demand that is the problem. Since you only have 100 amp service, you are probably in need of a serious upgrade to 150 amp service. The reason it's the outside breaker is that no two breakers trip at exactly the same point. In your case the outside breaker is tripping a little ahead of the inside breaker. High ambient temp outside also contributes to the outside breaker going first since the problem started in July with temps in the upper 90's. I bet when the temps are cooler- into Sept. as I right this reply, that the problem goes away. That doesn't mean the issue is solved. You are probably running close to 100 amp total load at least some of the time.

Forget trying to find the culprit inside your house panel. You need a service upgrade to 150 amps. Hope this helps.