220V --> SSR --> 5500W Heating Element Question

I'm in the process of building my electric brewery. I've been researching the various ways to supply power to the heating elements (1x SSR, 2x SSR's, Switch to Mechanical Relay to SSR).

It seems like using a switch and mechanical relay is the preferred method, mostly due to safety.

My initial thought was to run both hot leads to the L1 post of the SSR, and then from the T1 post, split the wire and connect it to each post of the heating element. Since there is no neutral wire in play (just a ground wire), I can't see why this wouldn't work.

Having not seen anybody else wire it up this way, I'm fairly certain it isn't appropriate. However, I'm hoping someone can tell me why.

Thanks,

Jeff

I don't think I follow what you have in mind - can you post a drawing?

I may not quite understand what you are saying, but DO NOT run both hot leads to one post on the SSR... they'll short out and trip your breaker. You want to run one of the hots through the SSR, the other connects directly to one side of the element. The manual switch (I have a 30 amp Double pole double throw switch) is for turning off both sides of the 220V feed.

When you cut one of the hots the element will be inactive. With my element you can touch the wort, element etc when one hot is cut, but cutting both when you are going to mess with it is a good idea none the less.

Also I really recommend having a GFCI breaker or some sort of GFCI in line to protect you further.

Here's my example of a similar setup:

excuse the drawings...unfortunately, it's the best I could come up with. Also, I know I left out the ground wires...just trying to simplify it.

My proposed method:



Suggested method using 1 SSR:


Thanks in advance for the enlightenment I'm sure I'm about to receive

l3asturd; your diagram is identical to Kal's design (theelectricbrewery). It's a good design.

To the original poster; what you're talking about is a dead short, and certainly will not work. It also shows a dangerous lack of understanding. Please, please do a lot more research before you start fiddling with this stuff. Be safe!

OP: Although those two wires are both 120V (wrt gnd), they are AC and 180 degree out of phase. Like previous posters said, it's a dead short.

You can't run both legs of your 240 off one post on the ssr. Putting both there will cause a short and probably some fire. Basically the ssr controls one leg while the other is constantly there. You should have a switch between the ssr and element as well, so the element gets no power until you are ready to start heating water.

or you could just get a dual output relay to control both hot legs like this one

http://www.mouser.com/ProductDetail...Flnt7DBZX%2bUDtnVpHDyG7OoCBNjw0dt9xaE0LNJOrs=

For added safety I, and others interrupt the red line in your second drawing with a Mechanical relay. I have this relay, but there are others you can use. I control it with a selector switch that will close it when I want power to that element. I have a micro controller (BCS-460) that controls the SSR, which is the main controller for the element.

You could use an SSRD like ajm suggested. They are typically more expensive than a cheap SSR and cheap mechanical combined. My original plan was to hunt down an SSRD and eliminate mechanical relays altogether but I'm glad I didn't. I would have SSR leakage on both lines and a LED indicator light fix would have been a lot harder to find.

Thanks guys for all the feedback and recommendations. In hindsight, yeah, it was a stupid question/thought. I haven't worked with 220v too much, more experienced with 110v with neutral.

I'm leaning towards the 2x SSR route without mechanical relays / switches. I'll have GFCI between the wiring the heating elements, and the plug that connects to my control box from the heating elements.

danmeljeff said:

Thanks guys for all the feedback and recommendations. In hindsight, yeah, it was a stupid question/thought. I haven't worked with 220v too much, more experienced with 110v with neutral.

I'm leaning towards the 2x SSR route without mechanical relays / switches. I'll have GFCI between the wiring the heating elements, and the plug that connects to my control box from the heating elements.

Click to expand...

Why not the relays? This is another safety feature. If you PID/SSR is off, one leg is cut to your elements. That means 240VAC isn't possible and our element will not heat. However, if you happen to touch the OTHER leg, it would still have a 120VAC potential and if you may provide the path to ground. When it comes to electricity, use as much safety equipment as possible. If you can't afford it, hold off a bit until you can. Of course the most important thing you can buy is a properly installed GFCI circuit.

Ultimately, I plan on building a fully automated system centered around the arduino; as in, push a button and a number of hours later I have 10 gallons of sweet liquid sitting in my fermentation vessel. It might be pie-in-the-sky, but something I'd like to do. Thus, if I have mechanical relays with switches, I'd have to turn the switch to ON for each heating element when I start the brew process. I rather just turn a single switch ON, when I'm ready to provide power to the entire control box.

With 2x SSR's per heating element, neither hot leg will be connected directly to the heating element...so I feel safe enough with this setup. I realize there will be a small amount of electrical leakage, and if one of them fails it'll most likely failed closed. If both fails at the same time, then I'm one unlucky individual. Also, with a GFCI inline between the heating element and it's plug, I think it'll be ok.

I'm certainly willing to listen to those who have "been there, done that".

Also...l3basturd, curious how you broke your 1 hydrometer as per your signature?

danmeljeff said:

Also...l3basturd, curious how you broke your 1 hydrometer as per your signature?

Click to expand...

It was a cheap POS and I was carelessly washing it in the sink. I think this is how 90% of them are broken. I bought a fancy Cole Palmer one and treat it like its a winning lottery ticket.