RF/spark?

[ptonsparky]

A few years ago I personally had a fan that when switched Off would trip the GFCI for the Freezer. Totally different circuits. I used a device from RK electronics to filter out the problem at the fan motor. IDR if I changed the switch at the time. I tried different brands of GFCIs with no success.

Today, we worked on a similar problem that was causing the TV satellite box to reset just about any time they switched Off the fan. Yup, just as they said but occasionally it would trip the bath GFCI. Different circuits. I have nice meters and voltage drop or interruption was not the problem. We replaced the switch to the fan with a commercial grade, what we had, and problem solved.

Are the fans the problem or is it that the switches are getting to be so poorly made?

 

[Sahib]

Inductive load such as fan generates spark when interrupted. This produces RFI with nearby electronics devices. If the interrupting switch is fast acting, the radiated energy in RFI would be less and there miay not be any problem.

 

[Jraef]

A few years ago I personally had a fan that when switched Off would trip the GFCI for the Freezer. Totally different circuits. I used a device from RK electronics to filter out the problem at the fan motor. IDR if I changed the switch at the time. I tried different brands of GFCIs with no success.

Today, we worked on a similar problem that was causing the TV satellite box to reset just about any time they switched Off the fan. Yup, just as they said but occasionally it would trip the bath GFCI. Different circuits. I have nice meters and voltage drop or interruption was not the problem. We replaced the switch to the fan with a commercial grade, what we had, and problem solved.

Are the fans the problem or is it that the switches are getting to be so poorly made?

Cheap switches are cheap for a reason. Contact material is often questionable and it could be that although technically "rated" for the fan motor load, switching the motor degraded the contacts more rapidly than might be expected. That then caused severe arcing, which then caused EMI/RFI issues in the entire circuit and it's possible that it could bleed over into other systems, i.e. the GFCI for the freezer. Your commercial grade switch might have some form of arc suppression, maybe small permanent magnets near the contacts that "blow out" the arc faster. Or it could just be that by putting in a new and better switch, the contacts are working better even without arc suppression.

 

[JFletcher]

Switches are generally the first thing I look at and replace, under virtually any troubleshooting situation.

take that for what it's worth (about a buck for a switch and ten minutes to replace it).