Do i need a relay?

[bucfanmike]

Im going to be wiring a fairly simple control panel. It is for a gas herms, it will have 2 pids controling the MT and HLT. These will have on-off-on switches for manual/auto control. There will be a 24v converter for the gas valves. The burner for the bk will be controlled with a 2 position switch, just on/off (no pid). There will be 3 switches for pumps (2 march and 1 submersible for recirc chilling).

Now i want to use both a key switch for security and a NC mushroom stop switch. Since my box will have such low power requirements can my incoming 120v run right through these switches or do I need to wire the keyswitch to a relay?

Thanks

 

[Hockeyman]

It all depends on what circuit you want your keyswitch to break. If you put it on the 120v side you can kill power to the whole box or if you place it in series with the 24v transformer circuit it kills power to the transformer, thus killing the 24v circuit. Or you can put it in series after the 24v transformer with the gas valves to just lock out the gas valves. What are you looking to lockout?

 

[Chrisl77]

I would put the switches on the 120v line as ssr's can leak voltage through and have a chance to stick on if they fail.

 

[bucfanmike]

I want the key and the mushroom to kill the whole box. I don't think it will be an issue because even with everything on I don't think I would draw more amps than those switches are rated for. As far as ssr's, they aren't any, being a gas rig, my pids will handle the switching of the 24v to the gas valves.

 

[Chrisl77]

Ok well I didn't know you where gas this is posted in the electric brewing section. I was thinking you where running 120v elements. If you want to kill the power to the whole box though you will want to put both switches on the main 120v lines coming into the box.

 

[bucfanmike]

thats what i was thinking chris, thanks. Posted in the electric section because its easier to get answers on electric issues.

 

[mattd2]

Something kind of offtopic, but kind of not, have you looked into getting a keyed mushroom e-stop? That would save wiring 2 switches, but don't know if the price for one keyed e-stop would be more than 2 seperate switches and would defeat the purpose?

 

[bucfanmike]

i didnt know there was such a thing. I already had the key switch and the two way switches, bought leftovers from someone here. Just ordered the stop and my three way switches from ebrewsupply.

 

[Chrisl77]

Good call on ebrewsupply. I ordered one of there diy kits and am completely satisfied with it.