Toggle switch question for heater and pump

[goldy222]

I'm working to design a control panel for a 2000 watt heating element with PID and SSR, and a pump. I want to use standard 20 amp toggle switches so I can turn power on and off to the pump, heater, and entire system. I see a lot of threads where a contactor is used with a switch to turn these devices on and off. Is the contactor/switch combo necessary, or will 20 amp toggle switches suffice as a safe solution? I'm not understanding the purpose of the contactors in these setups.

 

[P-J]

I'm working to design a control panel for a 2000 watt heating element with PID and SSR, and a pump. I want to use standard 20 amp toggle switches so I can turn power on and off to the pump, heater, and entire system. I see a lot of threads where a contactor is used with a switch to turn these devices on and off. Is the contactor/switch combo necessary, or will 20 amp toggle switches suffice as a safe solution? I'm not understanding the purpose of the contactors in these setups.

The contactor is placed in diagrams as the switches involved are not rated for the necessary current involved for the device in use. The contactor allows a switch rated for a minimal amperage to control a high wattage device.

Switch example: Illuminated Maintained Pushbutton Switch

The switch is rated for 10 Amps. When used for a 5500 watt element, a contactor is required.

Just saying... Hope this helps you...

 

[Saboral]

For the pump you will be fine.

For the heating coil a contactor or appropriately sized SSR is required.

If you're driving the coil at 2000watts at 240v you are looking at ~9 amps. At 120v you'd be at ~19.5 amps.

A pump will be well below the amp limit on your switch. However, one thing to look at is linking your pump switch to your heating control. This will stop the coil from heating if you don't have your pump on.

 

[goldy222]

I really appreciate the responses. There will be a PID and SSR controlling the heating element, but I was looking for a secondary method for turning power off when it's not in use, along with switching the pump and entire control panel.

Is there any reason why I wouldn't be able to use 20 amp toggle switches for switching power on and off to the heating element and pump, such as this switch:

http://www.amazon.com/dp/B006VZ4KP4/?tag=skimlinks_replacement-20


Again, I really appreciate the help. This is actually my first post, but I've found a ton of helpful information on this site over the past couple years because of all the great collaboration that goes on here.

 

[Saboral]

What voltage is the heater? What voltage is the pump?

 

[goldy222]

This is 120v on a 20 amp breaker. My understanding is the heater will pull 16.7 amps and the pump will be less than 2 amps.

 

[NathPowe]

I've seen diagrams on this site that use regular 20A SPST toggle switches (like this one for example) on a hot between an SSR and a 2000W element. I can't remember the thread that I've seen them in, but I definitely have seen them. Seems that a switch like that would work fine for a 2000W element, since it's pulling about 17A, and certainly fine for a pump.

However, there a lot of folks on here more knowledgeable than me so I defer to them if they chime in otherwise.

Cheers and good luck with your project.

Edit: Now that I think about it, I think the 20A switch was between the 120V/20A supply and the SSR, but either way it was still handling the ~17A required by the element in that particular design.

 

[Saboral]

based on calculations a 20amp switch for your main would be fine. One word of caution, the pump will draw a bit more right at startup. Probably not enough to fry the switch. I think it'll be fine.

The contactor just does the same thing your SSR does.

 

[goldy222]

This is great information. I did some additional research and found this setup diagram on Auber's web site that I may end up going with for the main and heater power switching:

http://www.auberins.com/images/Manual/2352-contactor.pdf

Thanks all for the posts here

 

[Saboral]

That would be great, but keep in mind this is for 220V coils. You indicated your coil was 110V


Sent from my iPad using Home Brew

 

[goldy222]

Auber's site says it's compatible with both. That link show 2 diagrams, the bottom diagram shows a 120v setup

 

[goldy222]

I misspoke, the contactors are specifically for 120v or 220v. The image had a diagram for each