Our kitchen is supplied by a multi-wire branch circuit to provide 2x 20-amp circuits. One circuit has the fridge and a single GFCI receptacle on it (the fridge is not protected by the GFCI receptacle). The second circuit has a GFCI receptacle followed by 2 additional receptacles on other walls. The neutrals for the GFCIs are not protected by the other GFCIs (I think this is called pigtailed). This circuit was last modified about 2 years ago and has been stable that entire time. The second circuit has a microwave and toaster oven on it, sometimes running at the same time which is definitely overloading the circuit as both have an audible change in sound when this happens (we do try to avoid this situation...). The microwave was also on a surge protector (which was rated high enough, but I have since read that the rating may apply to the entire strip and not each outlet).
In the last two weeks, the circuit has gone "weird". It appears as though sometimes the GFCI receptacle is almost but not quite tripping when placed under a small load (even just ~200W). The indicator light on it flickers green, sometimes flickering between green and red, but not tripping. During this flickering, the devices on the circuit lose power for an instant. However, there have been times when we have been able to still have the circuit under load without any flickering (like running the toaster oven, although at this point the microwave has been completely removed from the circuit).
So my questions are:
- Why isn't the GFCI actually tripping? Or why is it almost tripping without an apparent ground fault? (I have checked the wires in the receptacles and they all look)
- What needs to be fixed? Does just the GFCI receptacle need to be replaced?
- Did overloading the circuit cause the damage (to the GFCI receptacle or whatever else)? [we always planned to add an additional circuit, just haven't gotten to it yet]
- Is it possible the other branch of the circuit with the fridge has any damage to it (currently no symptoms though)