Is the RC-4 necessary? (again)

[BigRez]

A previous post asked this same question but for a specific application.  My question is more in general terms... Is the RC-4 really necessary to switch on/off 120vac devices?

I have an RC-4 with 4 SSRs and it's a nice, concise package,  but couldn't the same functionality be accomplished by connecting 12vdc relays to OUT1..x on the controller (or DC-16) and having the relays switch on/off the 120vac ?

Here's the deal... If I need to control sixteen 120vac devices, I'd need to get four RC-4 cards and 16 SSRs.  That's a good chunk of change compared to one DC-16 and 16 relays.  Of course I'd need to fabricate something to mount the relays onto and it may not look as nice as the RC-4 install, but cost is a factor.

So assuming the relay approach is correct, are there any advantages to using the RC-4 over relays? Disadvantages?

Thanks in advance,

[livinlowe]

You could do that, but your mount fabrication and wiring will take time, and probably not be as professional looking as the RC-4's. It really boils down to time - do you have the time and energy to homebrew your own system(and probably troubleshoot)? Then go for it. But if your like me, and your ambition is way higher than your time allows, I would just rather buy a RC-4 every month ot two and mount it.

[JonnyMac]

Necessary? No. You could use relays or SSRs connected directly to the controller.

A good option? Yes. And SSRs are aurally and electrically "quiet" versus the audible "clank" of mechanical relays and the noise generated by switch AC at any point in the cycle and the trash generated by contact bounce. 16 mechanical relays connected to a DC-16 will require some current, meaning another supply.  There are many factors, in my mind, that make the RC-4 advantageous.