Contactor Wiring

[hio3791]

I bought the Packard C230B (Contactor 2 Pole 30 Amps 120 Coil Voltage). It didn't come with any documentation and the website does not have any schematics.



The contactor doesn't have any markings. Does it matter which side is the hot side and which is the load? Does it matter which side of the coil I apply the power? I am guessing it doesn't matter but I thought I ask before I wire it.

And I have a related (contactor wiring) question, I bought the Auber SYS-2352 PID and SSR. Auber recommends wiring the contactor before the SSR but in PJ's schematics and Kal's drawings, the contactor is after the SSR. Any logical reason for doing it one way or another?

Thanks!

 

[heckels]

I had the same question when I got those. The contactors have no polarity. The 8 prongs on the front and back are for your 220v and the 2 on either side are for your 120v coil.


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[hio3791]

Thank you Heckles. What I particularly like about this contactor is that it has 4 prongs per leg. I am building a very simple controller so I can use the prongs off one leg to power the switches (with a fuse in between) and I don't need to get a hot bus. If however, I was powering more devices then I would need to get a bus.

 

[iijakii]

Thank you Heckles. What I particularly like about this contactor is that it has 4 prongs per leg. I am building a very simple controller so I can use the prongs off one leg to power the switches (with a fuse in between) and I don't need to get a hot bus. If however, I was powering more devices then I would need to get a bus.

You know, I have not thought of that before. I knew they had the prongs for that purpose, but on my last build I just went and got a bus anyways. On my upcoming one I was planning on not having an on/off because ultimately I'll never plug it in without it being on, so I don't care to add the cost/bling of another switch. But adding two buses might be getting close to the cost of a cheap contactor. Hmm.

 

[hio3791]

You know, I have not thought of that before. I knew they had the prongs for that purpose, but on my last build I just went and got a bus anyways. On my upcoming one I was planning on not having an on/off because ultimately I'll never plug it in without it being on, so I don't care to add the cost/bling of another switch. But adding two buses might be getting close to the cost of a cheap contactor. Hmm.

I don't know that the prongs are for that purpose but it's one piece connected to the screw terminal so it's a convenient way to use as a "mini" bus. My plan is to distribute power from one leg to switches for the PID, pump and contactor coil. On the "load" side of the contactor, I'll use the prongs to wire an LED in parallel across both legs (220V LED). It's a simple build on a small enclosure and having a dedicated bus would take up too much real estate (and unnecessary cost).

 

[Docbruw]

And I have a related (contactor wiring) question, I bought the Auber SYS-2352 PID and SSR. Auber recommends wiring the contactor before the SSR but in PJ's schematics and Kal's drawings, the contactor is after the SSR. Any logical reason for doing it one way or another?

Thanks!

Humm good question. Since I'm right in the middle of my build I'm curious what others say about this.

 

[Brumateur]

There is no real difference if contractor wired before or after SSR.

 

[processhead]

I used this same contactor in my panel and it works fine regardless which end is connected to line or load.

 

[kal]

Auber recommends wiring the contactor before the SSR but in PJ's schematics and Kal's drawings, the contactor is after the SSR. Any logical reason for doing it one way or another?

I put the contactor as the very last thing before the heating element receptacles for safety reasons.

If the SSR is still connected, while unlikely, there's a chance that something in the SSR could break and cause power to flow to the heating element.

I want the mechanical safety switch (ie: contactor) to be the gatekeeper so that when it's open the heating element is completely and physically disconnected from the control panel other than the ground.

Kal

 

[iijakii]

I put the contactor as the very last thing before the heating element receptacles for safety reasons.

If the SSR is still connected, while unlikely, there's a chance that something in the SSR could break and cause power to flow to the heating element.

I want the mechanical safety switch (ie: contactor) to be the gatekeeper so that when it's open the heating element is completely and physically disconnected from the control panel other than the ground.

Kal

But if the contactor is open not supplying power to the SSR, why would that matter? I don't see either way being better or worse.

 

[hio3791]

Thank you guys. Just wanted to confirm what I was thinking.

 

[kal]

The SSR is still physically (permanently) connected through the control wires that are not switched by the contactor.

If something disastrous was to happen, there's a slim chance that power could find its way to the element.

Again, it's an unlikely scenario, but since it doesn't add complexity or cost, I put the contactor as close as possible the heating element receptacles.

You want to minimize the travel path where things could happen (ie: loose wires, other issues you don't think about, etc). You want to keep the path as short as possible. Putting any physical disconnects as close to the thing you want to disconnect is part of designing with safety in mind.

Designing with safety in mind is often about thinking of things you'd never expect to happen. For example, what if someone works on the panel and leaves a wrench in there? It's looking at things that aren't expected to happen, things that may not be obvious: It may look the same or similar from a circuitry standpoint to do it either way, but it's not when you throw in things you never would think about.

Kal

 

[cjang]

Hi kal
I'm curious about you what you mean. I thought it would be safer to put the contactor as close to the power as possible (furthest away from point of use). That way, you deenergize more of the circuit when you disconnect. Am I not thinking about this the right way? Thanks.

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[kal]

It's not the innards of the panel we're concerned with but disconnecting the heating element from any possible current/power, so the safest way to do this is to put the contactor as close to the heating element/panel connection point as possible, minimizing the chance of something between the contactor and heating element/panel connection point from introducing current/power.

I'm not sure I'm explaining this correctly, but I can't think of a different way of explaining it.

Kal