Will this schematic work for my electric system

Can someone tell me if this would work for wiring my 4500 watt 240 volt water tank heater to my PID controller with SSR.

I kind of stole the idea from someone else but tweaked it abit.

My SSR is 40 amps. My PID works at 240v.

I put a switch in there so I wouldn't have to use 2 relays.

The black and white wires are the 2 hots.

i'm using a auber instruments PID

Was there supposed to be a link or photo? If so, I'm not seeing it - could be a problem on my end.

Rick

its up now I believe

Still no schematic.

Paul

Maybe this will show up; if not:
http://www.bodock.org/PostImages/2008/heating.jpg

I can see the image now, but it is hard to read. I don't know what PID you are using, but I will assume the connections are correct. What is the red block on the bottom left?

Paul

Leave out the switch, take the white wire directly to the heating element, take the blue wire directly to the relay. It's the same as you have assuming you leave the switch on; if you plan to switch the switch anytime the PID brings in the relay, you don't need to. With one line broken (by the relay via the PID controller) it won't heat. Make sure you use the GFCI breaker; make sure you are comfortable working with electricity.

Rick

The PID is from Auber instruments it is the one that is 45 dollars i'm not sure the model off hand.

The way I had it I was going to buy a double pole switch.

As far as electricity is concerned I know enough not to kill myself. I just wired my garage.

I haven't worked with 220V much but it seems the same as 110 just 2 hots instead of a neutral..

I have a 30 amp breaker that I will be running the element off of.

I have a switch that I will run my march pump off regular 110 that I will wire into my control box.

My reasoning for the switch was to have a way to kill power to the element if the SSR fails.

I was just reading up on this and an electrician had said that if you are not running 2 SSR that putting a switch in there is a safe practice.

I will work as Rick_R describes. Put the switch between the line and the power block if it will make you more comfortable having a local complete disconnect feature.

Paul

Then I loose power to the PID controller it's self. I just really wanted to kill power to the element not shut the whole unit off.

I'm not sure what good it is to have power to the PID if the element is not working, but it will work the way you have it in the original diagram.

You can't run the PID off of that 240V line like it is pictured.
You will need to run it on the 120V with the pump.

Make sure you oversize your SSR.
My brew partner ordered them a little too close to the needed amperage, and we melted 2 of them.

When you get it up and running there is a self calibration that you can run on the PID. Do this, otherwise they run very funky.

You can't run the PID off of that 240V line like it is pictured.
You will need to run it on the 120V with the pump.

Click to expand...

You can get a PID [edit: controller] that accepts 240V power; the OP suggests his does.

Rick

Rick_R said:

You can get a PID [edit: controller] that accepts 240V power; the OP suggests his does.

Rick

Click to expand...

The one he has will accept 85 to 264 Volts, but it still needs a nuetral.
American 240V is made by crossing two 120V phases. This will work for heating elaments. Electronics do not use the entire amount of eletricity provided, so they need a return path, ie: the nuetral.
This unit will run in the UK where they generate 240V 50hz as a single phase.

Electronics do not use the entire amount of eletricity provided, so they need a return path, ie: the nuetral.

Click to expand...

?

You can power electronics with standard US home 240V AC power; the electronics doesn't need to use "all of the electricity provided" (not sure what that phrase means); AC (alternating current) flows from one hot leg to the other, and back. This alternating current will be converted by the device to a lower DC voltage for the electronics. No neutral is needed. The device, however, must be designed to handle 240V AC -- and such devices are common in industry in the US. In fact, as a test, I googled "temperature controller" and the first page was for Omega temperature controllers. Clicking "more info" on their 7500 series came up with a supply voltage of 100 to 240 Vac, 50/60 Hz.

That said, I've no idea how the power grid works in other countries and no idea what the PID controller in question has been designed to accept, other than the original poster stating it was designed for 240V.

Rick

Plan9 said:

The one he has will accept 85 to 264 Volts, but it still needs a nuetral.
American 240V is made by crossing two 120V phases. This will work for heating elaments. Electronics do not use the entire amount of eletricity provided, so they need a return path, ie: the nuetral.
This unit will run in the UK where they generate 240V 50hz as a single phase.

Click to expand...

240V in North American homes comes from a Single Phase of a Three Phase power grid. (Notice there are always a multiple of 3 lines on large power transmission lines.) The secondary of the distribution transformer on the pole or underground near your home has a center tap. You get 120V if you connect between either of the outside taps and the center or 240V between the two outside taps. If you look at the two outside taps on a scope they will appear inverted. (Some people will call this 180 degrees out of phase. ) Usually the center tap is grounded and becomes the neutral. You do not need to connect to the neutral if the PID can run using 240V.

Paul

You have 2 diferent types of 240V appliances in your home. The ones with electronics, and the ones without.

The ones without have no neutral, (hot water heater)

The ones with have a neutral for the 120V timers and whatnot (oven, dryer, heater)

Plan9 said:

You have 2 diferent types of 240V appliances in your home. The ones with electronics, and the ones without.

The ones without have no neutral, (hot water heater)

The ones with have a neutral for the 120V timers and whatnot (oven, dryer, heater)

Click to expand...

You don't absolutely need a neutral for timers or electronics. Components are a little cheaper if they are designed for 120 rather 240, so many appliances use the neutral.

Paul

You have 2 diferent types of 240V appliances in your home. The ones with electronics, and the ones without.

Click to expand...

That's because the system uses both 240V and 120V power; bringing the neutral gives you both voltages. My dryer has no electronics but has a neutral because it has several 110V components; the light inside the dryer drum, the timer motor, the drum motor, and the buzzer if I recall correctly -- in fact, I think only the heater element was across the two phases. Some hot water heaters (tank-less, for example) are powered by 240V, no neutral, and have electronic circuits in them.

Having electronics has nothing to do with having or not having a neutral wire.

Rick