We have a Fellowes Powershred C-220C and the sensors for stopping it run in between shredding are not working - it keeps running while shredding - is there anyway to fix this??

Best answer is to check the Fellowes FAQ. It's an easy fix.
Shredder Running Continuously

Check and make sure there is no paper or paper dust covering the Bin Full sensor. underneath the head.

call fellowes for lay out

If your shredder has a feature where it won't run with the door open/shredder off the bin, you probably need to make sure that the safety is engaging properly. If the motor seems to sound very labored when it runs, unplug it, and check the blades to make sure there's not a lot of extra stuck in them. You may need to clean them and lubricate it with special shredder oil ONLY.

Blow some canned air down into the feed slot to clean the sensors.

The top sensors may be bad or even the main board that they are connected to is bad. Try cleaning them with a lightly moistened swab or compressed air. Fellowes will sell you the parts.

I’m happy to help further over the phone at https://www.6ya.com/expert/jayw_0e86fb055a7b73de

first off, fellowes has had problems with the bin full sensors that sometimes, can only be corrected by replacing them. however, there are two things to check. make sure it doesn't have a bunch of shredded paper hanging down from the cutters. that can trigger the bin light as the sensore are located under the head, but above basket. last, but not least, clean the sensors. they get paper dust on them after awhile causing same indication. if those two things don't fix it, it will have to have sensors replaced.

good luck,
razors

OK lets try.
You likely have a photo sensor that detects the paper and it is dirty.
It is likely covered with paper dust (hopefully only on the outside)
Locate the sensor and wipe it off or just wipe the entire throat area.
WITH MACHINE OFF
Hope this helps

i am not a service engineer of paper shreder

Seems it could be a problem with one of your sensors Fellowes Customer Service can easily and quickly diagnose your problem. 1-800-945-4545