Can I use 1 Transformer instead of 2 for my DSC Alarm System?


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Old 02-21-22, 06:32 PM
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Can I use 1 Transformer instead of 2 for my DSC Alarm System?

I have a PC1832 DSC alarm system. It has a PC5204 power expansion, 1 keypad with wireless, 2 nonwireless keypads, Eyezon EVL-4, 3 PC5108 zone expanders, 13 motion sensors, 6 smoke detectors, and 2 sirens. I added up the peak current draw for all of these and it totals to 1764ma. The transformer that I have is 16.5vac 40va. 40/16.5 = 2.42a = 2420ma. Assuming that that is the correct way to calculate it, I am well under the limit. Can I just run wires from the two AC terminals on my PC1832 panel to the AC terminals on my PC5204 expansion? I assume that they say to use a separate transformer because they can support sirens that draw a lot more current than mine do and in that case it would be too much for one transformer. Before I connect it that way, I just want to make sure, is there any reason I can't run it all off of one transformer by wiring it this way? Thanks in advance
 
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Old 02-21-22, 07:33 PM
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Welcome to the forums.

That panel can supply a maximum of 700ma of current for modules, powered detectors, relays, LED's, etc. If the total current requirement exceeds 700ma an additional DC power supply is required.

That additional DC power supply will also require a battery.

Keep in mind that transformer is 16.5vac and everything powered within the system is 12vdc.
That transformer can only power a panel or an aux DC power supply.

There are kits you can buy that are power supplies with an additional transformer. The ELKP1215 is a popular supply kit. Just add a 12v 4ah battery for backup. The Altronix ATX-SMP3 is a power supply only with no transformer.
 
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Old 02-22-22, 06:31 PM
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Thank you for the response! I actually already have all of the equipment that I need. I have the PC5204 additional power supply, a 2nd battery and I even have the 2nd transformer. The problem is I don't have a convenient place to plug it in without doing electrical work to add a 2nd outlet. So, that is why I was wondering if I can simply power both the panel and additional power supply off of one transformer.

I'm not sure I understand your point about the transformer being 16vac and the system running off of 12vdc. I know what AC and DC electrical circuits are but I don't know the implications here. Does this mean that I cannot attach both the panel and additional power supply to the same transformer? Thanks
 
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Old 02-22-22, 08:51 PM
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When you did your calculations you didn't figure in what the alarm panel and the external power supply require. Those two devices convert AC to DC and both require power to operate as well as power to charge batteries which is not a posted value.

Unfortunately one transformer will not be large enough to run both.
 
 

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