light switch trips GFCI on MWBC(?)

[rvcoaster]

i'm confused.

one wall of my garage has an MWBC with a GFCI on each leg. thats it for that circuit pair (two pole tied breaker)

ceiling lites occasionally trip either GFCI. if i stand there and flip the switch repeatedly one or the other GFCI will trip in a few seconds.

ceiling lites are on there own circuit and are unrelated to MWBC in question.

ceiling lites are older plug in t12 shop lites plugged into outlet boxes in the ceiling. (i would like to eventually upgrade these)

i'm thinking its gotta be something neutral related but i am confused. i did all the work myself.

one possible idea is that ONE shop lite has the ground pin removed by someone not myself. i guess i could remove it and se if this situation changes.

 

[pattenp]

Oh that's nothing. When turning on my fluorescent lights my flat screen TV randomly comes on.

 

[porcupine73]

I think sometimes GFCI's, esp older ones, can get confused by non-linear loads such as ballasts. When switching them on and off, the ballasts might be introducing harmonics that the GFCI's don't like.

 

[swaterbenny]

A wiring diagram exactly how you have it wired would be huge here. What's happening in theory doesn't happen, it sounds like it's two completely separate circuits. Ben

 

[rvcoaster]

its absolutely different circuits. they make no contact whatsoever.

 

[Provincial]

rvcoaster - try moving the neutral wires of the affected circuits so they are as far apart as possible. You may only be able to move them in the panel. They may be developing a harmonic that trips the GFCI.