What fuses should I be using between my controllers and SSR?

I am closing in on the final peices needed for my build. I have a 12v control bus that is powering my PID and my PWM. What type(model) fuses should I use between the control circuits and the SSR?

Also I am using a 120v March pump. Should I put a fuse on that too? If so what is the best way to go for that?

I am getting soooo close I can almost taste the beer flowing. I should be doing a test run in a few weeks.

I'm not an EE so don't take my word for granted...

That said, are you hardwiring your pumps or plugging into an outlet controlled by an SSR? If you are plugging into an outlet just install a GFI circuit to cover your pumps. As for your 12v control bus, fuses are not a bad idea, but you need to have a handle on the amount of amperage you will be drawing through it before you select the appropriate fuse. What other devices are you planning on running on here? Can you get either a watt rating or amperage draw of your 12v equipment?

My pump will be hard wired, with a switch on the control panel. 120v pump. The 120v leg will also be powering a 12v power supply. This will all be plugged into a GFI.

On the 12v side I will be drawing minimal amperage. PWM should not draw much. Maybe 1/4 amp. PID is 12v it will be drawing about the same. I will also be powering an electric ball valve that will be drawing about 100ma.

So all and all not much power. I was just concerned about SSR failure. If line voltage were to somehow get over to the Low voltage side. Should I have something so that the PID and PWM are protected from high voltage? I am not worried about the ball valve it is 12v and power supply is protected from over current.

There isn't much you can do to protect against over voltage. A fuse certainly won't help. A 14V transorb to grnd with some fuse protection may help but it may raise hell with the gfci. Tbh I wouldn't bother with it.

In my sig there is a link to an electrical primer, it addresses fusing for march pumps. I can't recall it off the top of my head right now.

CodeRage's primer was very helpful to me. You can check out the Simple Brewery Build in my sig to see my wiring diagram including fuses.

Thanks guys.

I think I am on my way now. I should be doing my wiring over the holidays. Just need to get the stand painted and I can start the wiring. Should be brewing on the new system in early january. I hope