I’m in an apt. and the power has been shutting off lately. It doesn’t trip any of the breakers in the breaker box inside the apt. but it does trip the master breaker on the box outside. Thought it was an oven issue but it still happens with the oven breaker off.
Visual inspection of the breaker box outside shows one of the wires looks a bit corroded. Wires to/from the rest of the units are a nice copper color. Is that a red flag?
Landlord is dragging their feet and telling us to talk to the electric company, and electric company is saying to call a licensed electrician, so I’m just trying to understand the issue so hopefully the landlord will listen to me.
I’ve experienced this breaker bypass issue a few times and in each case it was a ground fault.
Why this can bypass breaker and trip the mains: In most countries, the common inexpensive breakers in residential panel boxes are not GFCIs. They will catch and interrupt marginal overdraw before it starts a fire but won’t trip fast enough in the case of a ground fault, which is one of the reasons fire codes usually require GFCI outlets anywhere near running water. Since the mains in MDL and housing complexes are GFCI, they can trip faster than the subpanel breakers in the case of a ground fault.
One case that might be relevant to you since you had reason to suspect your oven: a microwave oven door closure sensor became misaligned and would intermittently fail to report closure. It was one of two that controlled a kill-switch relay for the magnetron (the main power drawing component in a MW). The easter egg in their circuit design was that if sensor A failed to report door was closed, the oven would simply act as if door was open, but if sensor B failed to report door was closed, closing the door would instantly cause a ground fault.
Diagnostic recommendation: get some GFCI adapters to use on any big AC appliances you suspect might be causing the fault, like the oven you mentioned, so that next time it happens only the culprit appliance will lose power and you’ll know what to repair/replace.
ETA: the GFCI adapters are common and inexpensive, and your landlord would likely rather pay for a few of those than an electrician visit. Either way, this absolutely is the landlord’s responsibility, especially if your lease includes the appliances.
We only have like 5 outlets in the house, would it be okay to put gfci adapters on all of them and plug extensions into the adapters?
Damn that’s convenient!
Yes, the simplest adapter style is a chunky wall wart, usually cheapest. Otherwise inline modules are common. For either, you just plug them in between the plug and its outlet and press the “reset” button. 15-amp 125v example from a common US supermarket ($14).
And if by extender you mean the multi-outlet strip extenders: yes, the adapter+extender would isolate the fault to just that strip. If ground fault occurs, everything on that strip turns off. You can also find power strips with built-in GFCI.
The only additional consideration re: which GFCI adapters you will need are
…or, if it’s just handling one appliance, take a picture of the power specification, usually a sticker on the back of the appliance, which should give you minimum amperage rating of GFCI
Edit: pictures
Excellent, I will grab a couple that will be especially helpful for the kitchen where we occasionally accidentally run the microwave at the same time as the kettle.
I’ll still prod the landlord to have someone come look at the power main issue.
That’s great. And glad youre pressing landlord. They’re very likely obligated to cover expenses related to this, but I understand landlords are shitheads and a PITA.
Just to be clear, re: MW+kettle example, typical GFCI won’t prevent that overload. Circuit breaker should trip. There is a similar component that does both (AFCI) but it’s more expensive and shouldn’t be needed if your breaker is functioning correctly. Adding GFCI is usually inexpensive enough to justify but is only meant to protect against faults, not overloads.
I see, thanks for clarifying!