ECC Forum

I couldn't find anywhere on the forums that specifically addressed this question so if I missed it and you know where I need to go I would appreciate the heads up.

I have decided to use the +5VDC to power the relays in MAN mode off of 3-way switches. But my question is: can I safely run the +5VDC to a terminal strip to supply multiple relays in MAN mode with the thought that there could be more than 1 or 2 devices running at once? Is the power supply that comes with the BCS beefy enough to handle that many devices (worst case scenario: both elements, both pumps and the A/C unit in the walk-in cooler)? Would a different power supply (wall wort or the like) be safer to use? Say one rated at 6-10VDC @ 2+ Amps instead of 1? Then wire the output from the transformer directly to the terminal strip and to ground, send a leg to the BCS for power, and jumper the rest for distribution for the MAN control of the devices. My first thought is that the one supplied has been evaluated for that eventuality but I am not 100% sure. I would rather err on the side of more Amps. I still plan on fusing everything but I want to make sure it is as safe as I can make it. Thanks in advance for any input you all may have.....

If you are talking about driving SSR relays in manual mode, then you will be fine. No difference than if the BCS were driving them. If you're talking about coil relays, then you need to see how many milliamps each relay draws and be sure that you are safely under the current that the BCS transformer is supplying.

Thanks for the response JonW. I was hoping that would be the case. Glad I dont have to go searching for another power supply....

If you have other DC voltages present in your control box, you can also use 12VDC or 24VDC on your HOA (manual Hand-off Auto) switches for the 'hand' position to signal SSR's or relay boards.

Link to post showing my diagram of doing this:
http://www.embeddedcontrolconcepts.com/ ... f=17&t=609

-mike