What brand would that be? Complex to remove the risk of melting the contacts on the controller, hence the need for a contactor. I have to agree that there is a risk for DIY, that's why the box is IP66, haha. I still have not seal the holes for wires with silicone yet though. Bring water tight, even if the components burn in the box, it should extinguish itself very rapidly. I also chose a proper rating wires instead of thinner wires for use in and out of box to minimise any overheating of cables (excluding DC power to fan since it is only 12V, 0.65A - max 1.3A, even so, wires are still thicker than those fitted by fan manufacturer).