switch / contactor for element selection

[conpewter]

I've been looking for 30 amp switches that work well on a control panel. I'd really like one that would be DPDT so I could use it to control what element was on instead of having a switch with two relays.

The power would go from that selector switch to one of two SSRs that have signal running to them from a single PID, I put the PID into manual mode when I'm using the boil kettle. It just seems like a waste of room to put in a switch plus two relays when I could do that work with one switch/contactor combination.

Any help on where to get the switch/contactor combination for a good price? I'm OK with ebay/china as I don't need to get this together too soon, my current system is working alright for now.

 

[trimixdiver1]

How about a 3 position switch to toggle the low voltage input signal from one SSR to the other?

 

[Bobby_M]

Ok, just one caveat for trimixdiver's response. SSRs fail closed when they fail. If you're OK with the possibility of both elements firing at the same time and the main breaker tripping out, then you're OK with only switching the control signals.

The Bryant 3025 is a 30 amp DPDT switch with center off. I think it's what you're looking for but it is $35. You could get two contactors and a LV switch for the same price, either way.

 

[conpewter]

Thanks

I had thought about switching the signals to the SSR and that was my original plan, but I do like what Bobby M is saying.

So I just bought 3 30 amp contactors on amazon for $20 shipped and I already have switches that I can wire to turn them on and off.

So the plan would be to put the contactors after the SSRs? So my PID control signal would go to both SSRs and then the contactors (controlled by a SPDT switch) would turn on one or the other of the elements.

 

[trimixdiver1]

Thanks

I had thought about switching the signals to the SSR and that was my original plan, but I do like what Bobby M is saying.

So I just bought 3 30 amp contactors on amazon for $20 shipped and I already have switches that I can wire to turn them on and off.

So the plan would be to put the contactors after the SSRs? So my PID control signal would go to both SSRs and then the contactors (controlled by a SPDT switch) would turn on one or the other of the elements.

I would put them before the SSR

 

[conpewter]

I would put them before the SSR

I was thinking that at first, but then got to thinking about the failure scenario of an SSR just staying on. But now the more I work through it you are right, it doesn't help/hurt that scenario. Plus putting it before the SSR will make it so that only one SSR can be live at a time, in the end I don't think it is a large difference.

Now I'm trying to decide between buying a new keyed switch or just using one of the on/off toggles I have to turn the whole panel on. Keyed has some cool factor to it, but I already have on/off toggles. My whole system has to be plugged in to the wall, so it's not like anyone can just accidentally flip it on.

 

[augiedoggy]

I used these in my compact build....
http://www.ebay.com/itm/New-OMRON-G...159?pt=LH_DefaultDomain_0&hash=item2c8b440e4f

 

[conpewter]

Thanks all!

Any opinion on using an aluminum enclosure for a control panel? I was told it was stainless but clearly it is not (now that I have it in hand)

http://www.ebay.com/itm/381013285520?_trksid=p2060778.m2749.l2649&ssPageName=STRK:MEBIDX:IT

 

[augiedoggy]

Thanks all!

Any opinion on using an aluminum enclosure for a control panel? I was told it was stainless but clearly it is not (now that I have it in hand)

http://www.ebay.com/itm/381013285520?_trksid=p2060778.m2749.l2649&ssPageName=STRK:MEBIDX:IT

Mine is plastic... ($36 12x12x6 from home depot electric isle). it really doesn't matter what its made of as long as its made to be an electrical enclosure... and even that is subject to opinion..... The enclose cost $3-10 to make and at least three times as much for certifications = $100+ after markups a metal box is a metal box..... for something like this the certifications are more politics and money in my opinion... unless they are made of magnesium which I hear is quite flammable and colorful to watch burn.

 

[conpewter]

Thanks I'm gonna shine it up and protect it somehow before I start drilling holes etc. I think it'll look nice in the end. Since it is aluminum I'm thinking of mounting the heatsinks on the outside and the SSR on the inside without cutting the square hole for them.