Yeah I had issues with Creeper Seeds blowing up Conveyer Belts and cables on my grinder too.
Then I remembered the Grinder covered a 5x5 area so I put it in a position where cabling is all protected properly and had the mobs all funneled into a pit so Creeper Seeds don't blow up the conveyer belts.
Could use a bigger pit, but it works well enough for what I need.
Actually, one thing that helps is to use that precision hammer. Hold it, see the area. Notice that you're thinking in two dimensions. it's not 5x5, it's 5x5x3-4 (can't recall exactly how many vertical spots it covers). But, the key part is that the Y axis coverage starts one block below the grinder, meaning you can put it up one high above the ground that it's covering and it fully covers the entire area and then some. This is very important. It may also be why my setups have never resulted in a grinder being destroyed. Just fluiducts.
Not at first, but my ultimate grinder setup utilizes drawbridges that roll out cursed earth (I did figure this out for myself, but then saw a vid or two doing this as well). I have a large room that has 4 5x5 areas with 4 grinders with one row of blocks going down the middle, and then a MFR spawner in the middle. I use rednet cabling to control that spawner on/off, and it's usually one or the other. I extend the drawbridges, allow cursed earth to make a ton of mob essence which gets put into a bunch of tanks, then when I want to use spawner, it drains the tank, then I flip switch to recharge tanks again, etc... It's a perfect setup as far as I'm concerned. In 111, I had that plus about 4-5 other cursed earth mini 5x5 rooms in apartment row right next to other setup which would collect me everything I needed to run my base through reactant dynamo.