Is an NTC thermistor needed for a 100VA r-core transformer? I want to avoid blowing fuses and uneeded strain on the mains switch.

Traffo will be used in a DIY CC/CV bench PS.

 

I guess that would depend on the rating of your mains supply/fuse/cable/switch ?

 

There is little use in adding a thermistor to this transformer. You do not state where it would be. Most of the places I could imagine placing it would either lead to no function to pretty sparks & smoke (once).

 

I was thinking of adding it in series on the primary side (220V) to limit inrush current to avoid too much strain on the mains power cable, switch, fuse, etc.

The traffo is used in a bench PS like I said above. Will it be fine to ditch the thermistor?

 

I'd just use a 2A fuse in series with the primary. Your circuit should have a fuse anyway.

 

Education:

http://www.ametherm.com/inrush-current/transformer-inrush-current.html

 

Thanks everyone. I will just use a fuse instead. If I'm not mistaken r-core traffos are not as bad as toroids when it comes to inrush current.