On Fri, 25 Oct 2019 08:36:08 -0500, dpb wrote:

On 10/25/2019 7:38 AM, DManzaluni wrote:
...

i wonder how much improvement I would see if I just change the offending CB from 15 amps to a 20 amp
CB? i have no real reason to think there is anything wrong with the
CB that keeps tripping, again, it ONLY trips when I leave that 1.5Kw
microwave on. I have no real reason to think it isnt just doing its
job. Properly.

What with what Clare said, i do accept that this microwave needs its
own CB but should a 5 amp increase in capacity suffice to prevent overload?


Not tripping the breaker isn't sufficient -- the breaker was almost
certainly sized based on the wiring and the breaker is there to prevent
overloading the wiring itself, NOT the loads on the circuit.

14 ga circuit wiring is NOT adequate for a 20A breaker; it would mean
pulling a 12 ga wire besides just replacing the breaker.

As Clare said, it _should_ have a dedicated circuit by current Code; but
the idea of just putting in a larger breaker is akin to putting a copper
penny in the base of the old fuse box...asking for serious trouble.

It would not hurt to replace the breaker with a new 15A one (or even
swap this one with another 15A one in the box) just to see if by chance
it has become more sensitive with age and consistent tripping. Does
happen...

That said, the real answer is to either distribute the load across more
existing circuits (without running extension cords all over to do so) or
add another circuit or upgrade the existing one--both latter
alternatives mean pulling new wire.


Try replacing with an HM breaker - high magnetic trip. Protects at 15
amps for steady load but allows a MUCH higher surge current. Normal 15
amp breaker will hold about 125 amps of surge. HM will hold over 300.