Relay triggered from 110/120vac but carries 240v load?

I need to understand which kind of relay to order can someone smarter help me? I have a 15,000 btu 240v air conditioner I would like to control with my 110v grow room controller.

110v coil 240vac 2 pole relay? Where the heck do I find an inexpensive one?

Edit:
Nevermind I believe I remembered enough to figure it out
https://www.grainger.com/product/DAYTON-Dayton-Enclosed-Power-Relay-WP5690705/_/N-/Ntt-30a+240v+dpdt+relay?sst=subset&s_pp=false&picUrl=//static.grainger.com/rp/s/is/image/Grainger/1EJG7_AS01?$smthumb$#nav=/product/DAYTON-Dayton-Enclosed-Power-Relay-WP5690705/_/N-qizZ1z0o4q0/Ntt-30a+240v+dpdt+relay?R=1EJG7&_=1459753216343&picUrl=%2F%2Fstatic.grainger.com%2Frp%2Fs%2Fis%2Fimage%2FGrainger%2F1EJG7_AS01%3F%24smthumb%24&s_pp=false&sst=subset

You could use this (select 110V version) for $5.99: http://www.ebay.com/itm/400986323109

110V (L and N) goes through "power" and 240V (L in and L out) goes through "switch". You could set it to always on if you want the grow room controller to control it or you can use the inbuilt programmable timer too as a bonus.

If you don't want a timer included you could just get this for $3.75: http://www.ebay.com/itm/311370281363

The Dayton relay you linked to is DPDT. I don't see why you'd need one of them for this application although it could be made to work it might be slightly confusing for you.

you want a contactor not a relay

- Jiji

jijiandfarmgang said:

you want a contactor not a relay

- Jiji

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You could use a relay or a contactor for this application. A contactor would cost 2-3 times more and have double the terminals to wire up. So I can't really see any advantage in picking a contactor? The $3.75 relay I linked to is rated at 6kW 240V so would handle the load easily. Genuinely would like to know if I'm missing something.

loftygoals said:

You could use a relay or a contactor for this application. A contactor would cost 2-3 times more and have double the terminals to wire up. So I can't really see any advantage in picking a contactor? The $3.75 relay I linked to is rated at 6kW 240V so would handle the load easily. Genuinely would like to know if I'm missing something.

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Well for starters I wouldn't wire in a no-name brand 3 dollar relay made in China in my grow room.

A definite purpose contactor is cheap. If you can't afford 10-25 dollars, then grow outdoors.

I'm not an electrician or pretending to be one, but I've been around the block.

Open up any piece of HVAC equipment with a motor, you'll likely see a contactor. They are heavy duty and reliable.

- Jiji

jijiandfarmgang said:

you want a contactor not a relay

- Jiji

Click to expand...

I ordered that relay I listed above already. What contactor would you use can you link an example?

Edit: Contactors don't list the voltage of the contact just the coil voltage

jijiandfarmgang said:

Well for starters I wouldn't wire in a no-name brand 3 dollar relay made in China in my grow room.

A definite purpose contactor is cheap. If you can't afford 10-25 dollars, then grow outdoors.

I'm not an electrician or pretending to be one, but I've been around the block.

Open up any piece of HVAC equipment with a motor, you'll likely see a contactor. They are heavy duty and reliable.

- Jiji

Click to expand...

That's not really an answer lol

10-25 dollars? Don't be cheap! Why not spend $100? or screw it if you can't afford $1000 for a contractor just give up and grow outside. If we applied that logic to everything we'd all give up or go broke.

If it meets the specs for the application then there's no reason to spend more time and energy getting something else. Relays and contractors are both electromagnetic switches and would work fine in this application if they're running within specs.

Thanks loftygoals. I already ordered that one and I need it to run a/c on the controller.

loftygoals said:

That's not really an answer lol

10-25 dollars? Don't be cheap! Why not spend $100? or screw it if you can't afford $1000 for a contractor just give up and grow outside. If we applied that logic to everything we'd all give up or go broke.

If it meets the specs for the application then there's no reason to spend more time and energy getting something else. Relays and contractors are both electromagnetic switches and would work fine in this application if they're running within specs.

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You ever see a grow room fire?

Is that low quality print of a CE certification mean anything? Do you think its even real? Are you going to rely on those few specs that are misspelled?

I only use UL listed or CSA certifed things in my grow room now.

I'm not going to debate why contactors for motors or larger loads. Its been beaten to death, do a search here or on the internet. I'm sure there’s more qualified people than me lurking to chime in.

Start by googling why should I use contactor for inductive load.

MeJuana said:

I ordered that relay I listed above already. What contactor would you use can you link an example?

Edit: Contactors don't list the voltage of the contact just the coil voltage

Click to expand...

They do list the ratings of supply voltage.

I use one of these for my dehumidifier.

http://www.amazon.com/Eaton-C25BNB220A-Definite-Contactor-Inductive/dp/B008KNAQ3K

It's more expensive than I needed, but I liked the idea of a sealed coil.

- Jiji

Info: Contactors and Relays perform the same task of switching a circuit. If you see from the application point of view, you would have seen contactors placed in control panels of industrial motors or other heavy loads. Whereas, relays are used in low voltage applications such as switching a LED or tube-light or even actuating a circuit breaker .

Both are electromagnetic switches and operate under similar principles. The difference comes if we see from the application perspective. Contactors are used for high voltage switching purposes whereas relays are used for low voltage switching.

Some more info:
Difference between Contactor and Relay

• Since a contactor is required for a higher load, a relay is always cheaper than a contactor.

• A relay is normally used in appliances below 5KW, while a contactor is preferred when the appliance is heavier.

• A relay is used only in control circuit while a contactor can be used in both control and power circuits.

• In general contactors are little slower than relays

• Contactor is so designed that it can be repaired while it is not normally done in the case of relays.

MeJuana said:

This thread isn't actually helping me because I am too dense to understand, I don't have a knack for electricity at all. I am going to unwatch it before I make everyone hate me because I have an extremely bad temper. Have fun with the thread, I am going to find specific help from an electrician forum.

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You want a contactor not a relay.

I checked with an electrician at Grainger. I am being trolled guys a power relay is fine for this.

jijiandfarmgang said:

You ever see a grow room fire?

Is that low quality print of a CE certification mean anything? Do you think its even real? Are you going to rely on those few specs that are misspelled?

I only use UL listed or CSA certifed things in my grow room now.

I'm not going to debate why contactors for motors or larger loads. Its been beaten to death, do a search here or on the internet. I'm sure there’s more qualified people than me lurking to chime in.

Start by googling why should I use contactor for inductive load.



They do list the ratings of supply voltage.

I use one of these for my dehumidifier.

http://www.amazon.com/Eaton-C25BNB220A-Definite-Contactor-Inductive/dp/B008KNAQ3K

It's more expensive than I needed, but I liked the idea of a sealed coil.

- Jiji

Click to expand...

Sorry mate. You're talking nonsense. It's not been beaten to death anywhere. If you use a part within its rated specs then you should be fine. For *this application* the relay I linked is perfectly fine (the contactor you linked would be fine too). I don't really get why you're trying so hard to confuse the matter with talk of fake parts.

The poor OP was asking for advice and you're just confusing him for no real reason. He's even had to go away and ask an electrician. smh

So this relay is installed and working, it doesn't get hot at all and the room is cool. There is an extra set of poles @ 240v that I can use to trip another relay so I could continue the daisy chain, but also I learned it is ok to pigtail low amp items such as triggers. (In other words I can just use the 110/120v trigger line and pigtail to another relay)

If you end up with this relay here's the terminals I used: (Alternating current so it doesn't matter which wire color)
110/120v Trigger = Terminals 1 and 0
240 Line = Terminals 2 and 6
240 Load (out) = Terminals 8 and 4

P.S. The diagram on the relay is fairly clear after you study it a minute but I confirmed with a multi meter which contacts closed