This one costs more, but might be worth a look. It's an electronic breaker with spike protection. Amperage setting are adjustable, 4 settings from 4 or 5 amps to 15 or so amps. Here is the info PSX-AC from DCC Specialties I have been using them with Lionel PH-180s and they work really fast. I have mine set for 8 amps (closest setting they have to the 10 amp PH-180) and they always trip before the PH-180s. Haven't blown anything so far in about 3 years or so.
I believe these are still available from Charles Ro, just the PSX-AC istelf. Tony's Train Exchange has them and also carries a screw terminal kit and the sonalert alarm device. I believe they also provide pretty good support on these devices. Of course you would need one fore each output of your ZW used for track power which would run up the cost. Make sure you get the AC version if you choose to order these.