I had to search to find your duct thread (it disappeared on me- this thread did also?) to check if you have a mitersaw. Mitersaws are a special case, since most are used for multiple short bursts of a few seconds at most, they are not ideal for auto-gates and especially ones that also automatically start the DC. Though my mitersaw blast gate, like all my others, is electro-pneumatically operated and when activated starts the DC, it is not automatic- I must flip a switch to open the gate. I also have a 2.5" shopvac line running via manual blast gate to the saw's blade guard port. The loud shopvac is in a cabinet for noise reduction. It is activated via a separate low voltage circuit and relay by a different set of contacts in the manual DPDT switch that controls the DC blastgate.