I should check. It is whatever came in it when I bought it. So far the fuse has not gone out.The headlight harness (I assume you're using the driver side as it's closest to the fuse box) just provide power to the relay which then allow direct power from the 12V battery to the ballast. So the stock headlight harness should not be a concern.
Another note, what is the Amp rating on the relay you have installed? The one i'm using is 40A.