Selector Switches and Contact Block question

[Thehopguy]

I'm trying to wrap my head around switches and am getting more confused than anything. I finally understand the difference between NO and NC, and somewhat understand the differences between SPST/SPDT/DPST/DPDT. But what I don't understand is the reason for having 1 Contact Block vs 2 Blocks.

To simplify, how are these 2 Selector switches different and why and when would you want a second block.

2 Way Selector 1 NO contact
http://www.ebrewsupply.com/2-way-1-no-contact-switch/

2 Way Selector 2 NO contacts
http://www.auberins.com/index.php?main_page=product_info&cPath=7_32&products_id=241

Pretty much I'm looking for a simple ON/OFF selector switch to control power to the actual control panel and 2 more for my pumps.

And secondly, how do selector switches vary from a simple rocker switch? I see the selector switches have Contact Blocks and a rocker does not, do they function the same?

I will also need 3 way switches for the automation of my HLT burner with AUTO/OFF/ON options.

What is the main difference between these 2 switches
3 WAY Selector with 2 NO Contacts
http://www.ebrewsupply.com/3-way-2-no-contact-switch/

3 WAY SPDT Rocker switch
https://www.radioshack.com/products/spdt-6amp-switch

 

[woo_pig]

Do you want a on off switch to power separate switches for each pump and the panel?

 

[Thehopguy]

I'd like a main power switch. And also 2 ON/OFF switches for each pump. I assume all 3 of these can be the same type of switch right, SPST?
A lot of people have used the following from RadioShack:
https://www.radioshack.com/products/spst-6amp-lever

I'm just trying to find a comparable Selector switch that will serve the same function. I found these 2, but don't know the difference between 1 NO contact block and 2 NO contact blocks
1 block:
http://www.ebrewsupply.com/2-way-1-no-contact-switch/
2 blocks:
http://www.auberins.com/index.php?main_page=product_info&cPath=7_32&products_id=241


And for my automation I'd like a AUTO/OFF/ON switch. I see a lot of people use these from RadioShack:
https://www.radioshack.com/products/spdt-6amp-switch

Again I'm trying to find a comparable selector switch to use that will serve the same function. I think either of these will work but I'm not sure how to use the contact blocks as opposed to the configuration on the back of the RadioShack rocker.
http://www.auberins.com/index.php?main_page=product_info&cPath=7_32&products_id=235
http://www.ebrewsupply.com/3-way-2-no-contact-switch/

 

[Bobby_M]

Toggle switches are permanently configured The 22mm selectors and push buttons allow for reconfiguration with use of stackable contact blocks. Think of the NO and NC states as the operator being in neutral position. An On,Off, On (double throw) toggle is the same as a 3-way selector with two NO blocks. In the case of the toggle, a single common flops between two NO terminals. With blocks they are two completely separate sets of contacts, but you can wires them to operate the same as the toggle.

 

[Thehopguy]

Thanks Bobby. Definitely clears a lot of things up. To elaborate further, could you give me an example of when you would use a 2 way selector with 1 NO contact block opposed to when you would need a 2 way selector with 2 NO contact blocks. I guess I don't understand the need for more blocks. Do you need more blocks when you are lets say going to have an LED indicator light turn on with your pump? Is that not possible with a single contact block?

 

[sam]

Thanks Bobby. Definitely clears a lot of things up. To elaborate further, could you give me an example of when you would use a 2 way selector with 1 NO contact block opposed to when you would need a 2 way selector with 2 NO contact blocks. I guess I don't understand the need for more blocks. Do you need more blocks when you are lets say going to have an LED indicator light turn on with your pump? Is that not possible with a single contact block?

You don't need more blocks if you can jam multiple wires into the terminal screw on the block. Two wires (one to pump and one to LED) in one side of a block won't be an issue.

See Kal's diagram:

 

[Bobby_M]

Thanks Bobby. Definitely clears a lot of things up. To elaborate further, could you give me an example of when you would use a 2 way selector with 1 NO contact block opposed to when you would need a 2 way selector with 2 NO contact blocks. I guess I don't understand the need for more blocks. Do you need more blocks when you are lets say going to have an LED indicator light turn on with your pump? Is that not possible with a single contact block?

A 2 way selector has two states.. When the contact block or blocks are "normal" as in "NO" and when they are abnormal (when an NO is in the closed position). A two way selector with one NO block is a single circuit switch between Open and Closed. You would stack blocks on a 2 way if you want to 1) make multiple separate circuits open or close at the same time with only one operator control. In a lot of circuits, you can't just jam them all into the same blocks if the circuit designs don't allow it. Like what? How about switching both a 120vAC and a 12VDC at the same time. 2) Stacking different blocks like an NO and a NC together lets a way selector act like a double throw switch, that is being able to attach power to this or that. This element or that element. This usage doesn't inherently have an "off" state as that would require a 3 way.

The best education on this is to buy a 2way and 3way selector with a few blocks and watch what they do in your hands.