I have a client that would like to order a wedding cake that features a chocolate ganache dripping down the side of a fondant covered cake.
I have never attempted this and wondering if any of you have and any tips or techniques you would care to share with me please?
My concern is the temperature of the ganache when it's pourable, sitting on top of fondant.
Seems like it would break down the fondant?

You just have to let it cool down. Even if I leave mine out overnight on the counter, it's still softer than peanut butter. I use Rose Levy Beranbaum's ratios from the Cake Bible.