You can use a non-fusible disconnect on any load that the correct overcurrent protection is already installed.
Say a HVAC unit that has the correct overcurrent protection at the panel, why spend extra money on a fusible switch and fuses, this can be a lot of money when it is a large 600 volt rated switch and fuses.
You may use a fusible switch any place that a non-fusible switch is presently installed and you can even get "non-fuse" 'fuses' for the switch.
These are UL listed devices to make a fusible switch non fused.
Bob Badger Construction & Maintenance Electrician Massachusetts
#36107 - 03/28/0403:02 PMRe: non fusable disco question
One additional note to Bob's. A non-fusible disconnect generally has a withstand value (capability to resist explosion during a fault) of 5k and sometimes 10k, depending on the manufacturer. A fusible disc., with fuses, has a withstand/AIC generally of the fuse AIC rating. So just check fault current available before selecting.
#36109 - 03/28/0410:57 PMRe: non fusable disco question
We use many non-fusible disco's at the quarry where I work. We use them as a disconnect between every motor and starter. All of our fuses are located with with the starters in one cabinet. Therefore we have seperate disconnects that we can lock out to work on that piece of equipment. It seems to work good.
It also makes it simple to reverse rotation on a motor ( 3 phase ) without exposing yourself to a great danger.
#36110 - 03/29/0405:07 AMRe: non fusable disco question