Answered by Shaykh Faraz Rabbani
Does changing a baby’s diaper break one’s wudu?
Answer:

Walaikum assalam wa rahmatullah,
No it does not. However, it would be best to wash one’s hand after.
As for what breaks one’s wudu, please check the Hanafi Fiqh archives at www.sunnipath.com
Wassalam,
Faraz Rabbani