WOOF! - The Complete Series 1 (Original episodic version):

Eric felt a curious tingling in his hands and feet. He felt his nose becoming cold and wet, his ears becoming flappy. The thought in his mind was: 'I'm turning into a dog!' Eric is a perfectly ordinary boy. Perfectly ordinary that is, until the night when, in fifteen seconds flat, he turns into a dog! Eric and his best friend Roy are determined to sniff out the truth - what makes an ordinary boy suddenly go 'woof'?

Classic light hearted childrens drama  from 1989                

CAST:

Liza Goddard ... Mrs. Jessop
Edward Fidoe ... Eric Banks
Thomas Aldwinckle ... Roy Ackerman
Lizzie Mickery ... Mrs Banks
John Bowler ... Mr Banks
Sinead Rydquist ... Emily Banks
Constance Lamb ... Mrs. Ackerman
Juliette Fleming ... Joan
Natasha Knight ... Allison
John Ringham ... Mr Blocker