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-   -   Allen-Bradley Contactor Wiring Help (http://www.homebrewtalk.com/f170/allen-bradley-contactor-wiring-help-381675/)

ironmountainbrew 01-15-2013 02:35 PM

Allen-Bradley Contactor Wiring Help
 
I need help. I purchased 4 Allen-Bradley C30 Contactors last year from zeus53219 (http://www.homebrewtalk.com/f16/cont...ements-273489/), but just now getting around to wiring my control panel. (I posted this Q in his classified as well)

The plan is to use 2 of the C30's together to bring in the 50a service. Then the other 2 to be used on each of the elements.

I understand the element wiring concept just don't know exactly where to stick the wires. Can someone please post a really good pic or an easy to follow diagram?

Now, combining the 2 contactors to bring in the 50a service is where I'm really confused. Can this be done, and obviously, if so, can someone please explain.

Thanks in advance.

JRems 01-15-2013 08:31 PM

Why would you need 2 contactors to bring in the power? You should only need to use one contactor to allow both hot wires to be connected. I don't know why you would need or want a contactor for the neutral and ground. Unless I am misunderstanding. Can you post a wiring diagram you are using?

Intimnasc 01-15-2013 09:38 PM

Yes it absolutely can be done but should not be done. Calculate your total load not counting incidental loads twice and get the proper size relay. Here is why I say this. Say the relays are rated for 30 amps each and you wire them in parralell to split the load. They may work for a while until one fails and the other gets full load and blows up causing alot of damage to any other components mounted close. If they are rated for 50 plus amps just use one if not get the correct size.

stevehaun 01-15-2013 10:16 PM

According to your link, they are rated for 30 amps. You should not use them to bring in the 50 amp service. They can be used to control one 5500 watt element. To control the 50 amp service, you need a contactor that is rated for a 50 amp resistive load.

ryane 01-15-2013 10:17 PM

1 Attachment(s)
You cant split the current between two contactors because in a 240V single phase center tap application the current flows between the two hot legs of the circuit

The link you posted said the contactor is good for 28A at 240V, so youll blow the contactor when using a 50a load.

If you want a cheap 2phase 50A resistive contactor you can get them HERE for ~$11 each plush shipping

once you get the correct contactors, you wire them up like the picture attached, although if your having trouble understanding the contactors you might want to reassess what your attempting, tell us everything you want to do, and we can all help to make sure your set up is safe

ironmountainbrew 01-15-2013 10:48 PM

1 Attachment(s)
I made an assumption based on a diagram from ebrewsupply. It appears that he is using two 40a contactors to pull in the 50a service. I was really just double checking, but sounds like I may have been mistaken on how to use the contactors.

http://www.ebrewsupply.com/designs/P...D-Electric.pdf

He's using 1 40a contactor in to the ssr and contactor for one of the elements. Then the other to the 15a breaker and down to the other ssr and contactor.

I'm going off a diagram P-J created, but had assumed the two contactors would work based on the above diagram and was trying to figure out how to use the two contactors I had.

Here's the P-J diagram:

ryane 01-15-2013 11:46 PM

In the diagram posted from ebrewsupply, there are using two contactors where I would only use one, also each of their contactors are rated @ 40A resistive, not 28A

If you want to do this I would purchase a 50A contactor, use a single contactor to turn power on as I showed in the diagram and then you can use your c30s downstream, although I would just buy enough 50A contactors do it all , after all $20 extra isnt that much, and then everything downstream is rated to the input current (I would add fuses prior to the elements if you dont use the breaker as per PJs diagram to limit the current to 30A - this is needed to protect the 10awg SO cord you would use to run to the element)

ironmountainbrew 01-16-2013 03:21 AM

Thanks for all of the replies. Sounds like I'm going to order a 50a contactor to bring the main in and just go w what P-J provided. I liked the idea of using AB because they are higher quality and were a good deal from Zeus. Too bad I didn't know what I was doing when I bought them. Oh well. I'm sure I can sell the 2 contactors that I wont use to pay for a 50a.


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