Mcrow

I installed 8 pelco spectra ptzs and 6 sensormatic ultra ptzs. They are all in a row. I am using 1 power supply to power all 14. It's a 24vac 18 channel model ps-a1805, taking 120vac into the power supply and stepping down to 24vac to power the cameras, which are all 24vac. The whole thing works great for about 48 hours. Then the transformer in the power supply burns out. So I replace it. 48 hours later, same result. I tested all power lines cannot find a short. Any ideas?

thank you

Hardwired, thanks for the info and the link to the calculator. Im using 18/2 power cable, i do have a couple ptzs that are about 175 feet, the calculator says 150 ft should be the max. I installed the new power supplies last night, so far no issues

Thank you all for your help. 5amp power supply is obviously not cutting it, I made the mistake of reading 1.1 amp/channel on the packaging and then multiplying that by 18 channels = 18.8 amps. Clearly wrong, 1.1amps is the max current a channel could provide. In hindsight, I am surprised they lasted 48 hours. Ok so now I am planning on ordering two 15 amp power supplies, and splitting up the cameras between the two. Any reason this should not work? The pelcos draw 30vA, which is 1.25amps (according to the specs I found online for spectra II) and the sensormatics draw .85 amps to 1.5 amps (according to the specs I found for the sensormatic ultra). So 1.25 x 8 =10 amps & 1.5 x 6 =9 amps, based on this I am thinking two 15 amp power supplies will suffice.