12V Relay

[brucecampbell]

Is there any problem with using the same relay connections from my HC800 to run two relay?
Can I assume that as long as the voltage drop over two cables does not prevent the relay closing, this will be just fine?

 

I simply have two garden light transformers running independent circuits, each is hooked up to a relay.
I don't need independent control, simply want both on and off at the same time.
And I have limited connections available on the controller.

 

 

[Cyknight]

18 hours ago, brucecampbell said:

Is there any problem with using the same relay connections from my HC800 to run two relay?
Can I assume that as long as the voltage drop over two cables does not prevent the relay closing, this will be just fine?

 

I simply have two garden light transformers running independent circuits, each is hooked up to a relay.
I don't need independent control, simply want both on and off at the same time.
And I have limited connections available on the controller.

 

 

So you're running two 'external' relays and operating them from an HC800 relay connection?

Shouldn't be a problem, unless those relays require some insane amount of amps to keep closed.

[brucecampbell]

1 hour ago, Cyknight said:

So you're running two 'external' relays and operating them from an HC800 relay connection?

Yes

1 hour ago, Cyknight said:

Shouldn't be a problem, unless those relays require some insane amount of amps to keep closed.

Thanks, I was hoping that would be the case.

Does the HC800 have a set amp per 12V connection or is there a max amp total for all four connections?

[Cyknight]

Off the top of my hat, 36v AC or 24v DC - either one at 2 amps. That's per relay (it really is just what the controller's relay material is rate for)

Note that an avergae relay won't post the amps used, but is generally under 0.2 amps each.

[brucecampbell]

54 minutes ago, Cyknight said:

Off the top of my hat, 36v AC or 24v DC - either one at 2 amps. That's per relay (it really is just what the controller's relay material is rate for)

Note that an avergae relay won't post the amps used, but is generally under 0.2 amps each.

Great, thanks!

 

Also - should I be considering adding a fuse to protect the controller?
Is it possible a relay can short and send 240V along the 12V cable?
What sort of fuse and what Amp rating would I use?
 

Pic of relay in use:

 

 

[Cyknight]

You shouldn't have to - the chances of a short in the relay itself are next to nothing - if anything it would happen if the wire connections get messed up, are left too long, etc.

If you wanted to add a fuse, it would depend on the trigger voltage for the really. Most are DC, but it could be AC. If it's a DC voltage, you can get cheap inline fuse holders that take standard car fuses. Car fuses are generally rated up to 36VDC, just like controller relays are. Amps don't matter too much, but I'd probably want to get a lower rated one, like 5A or even a 3A