This is the SSR Part #:

**"TLP3546A(TP1,F"**

The SSR is 3.5A, but can support 10.5A pulse for 100ms.

I am planning on limiting this to around 1.0 amp, and I would like to use a PTC resettable fuse. This one for instance:

PTC Fuse Part #:

**"2920L110/60MR"**

The PTC has a hold current of 1.1 amps, trip current of 2.2 amps, and a maximum amp rating of 20 amps before breaking.

**The main thing I want to protect against is an accidental short circuit.**

PTCs are not very fast - in this case it will take 500mS to start heating up, increase in resistance, and finally enter its "tripped" state.

So it seems the SSR will become damaged before the PTC trips? And the PTC fuse also states that it can only withstand a maximum current draw of 20 amps before breaking.

Do I need to insert a series resistor to help limit current draw? For instance, if I placed a 1.8 ohm resistor in series with the 24VAC transformer, and the load, this would limit the current to 18.8 amps - and buy just enough time to protect the SSR while the PTC starts to heat up and reduce current draw itself? Not sure if its supposed to work like that. Also, I don't think these 24VAC transformers are actually capable of sourcing 18.8 amps anyways. And they do have PTCs that have a breaking amp rating of 100, but I thought this was still a good example.

I'm just a bit confused how to go about this. I am not sure if I am making this overly complicated or not.

Any help or advice is greatly appreciated, thanks!