I am wanting to control an AC line (~120V, 20A max) (a normal house outlet).

I'm trying to figure out whether a mechanical relay or an SCR would be better. A mechanical relay will probably be bigger in size, and require a bigger current to throw(which will affect the current specs of my AC/DC converter). But, an SCR has an average power dissipation of alot more normally(so I've read).

Is the above correct? Ideally I want to draw little current overtime, so a low power 20A scr would be ideal, but I keep seeing average dissipation of about 0.8W.

Any advice is much appreciated!

 

What are you wishing to control? Are you aware that an SCR is unipolar? If you need full AC power, you should think of a TRIAC, or perhaps a solid state relay (SSR). Both the TRIAC and SSR will need heat sinking is operated above a level of a couple of amps.

 

I'm wanting to control a wall outlet.
So would you recommend using a TRIAC/SSR heatsinked (thinking size might be a bit of an issue) or a mechanical relay?

 

An ordinary wall switch will do as much. Is this just on/off?

 

Yea, it's being controlled with a microcontroller wirelessly. Sorry, I forgot to mention that earlier.

 

Actually, that makes a difference. You might consider using a relay (I find P & B PRD series relays pretty bulletproof) with an optotriac to control it.