Relay Expansion/Relay Box questions

MDB1029 · Post by **MDB1029** » Tue Feb 17, 2015 5:14 pm

So I am having a little bit of difficulty figuring out what hardware I will need.

My problem is my sump and where I want the RA and primary relay box is about 40 feet from my DT. So I plan on buying a Relay Expansion and a long VMA cable so I can control the lights pumps fans etc. I have LEDs and want to be able to dim them but there is no dimming port on the expansion relay box which is activated, right? If I am wrong let me know.

So I think i would have to have a dimming expansion ,which also can not connect to the relay box? If it can't then i would need an expansion hub and a very long bus cable, right? If this is the case, what bus cable would i need to find? The one which comes with the dimming exp will not be long enough.

I am not sure if i am explaining this very well so if you are willing to help and i don't make sense just ask and I will try to clarify for you. TIA

lnevo · Post by **lnevo** » Tue Feb 17, 2015 5:39 pm

You can have the dimming leads from the dimming expansion travel a pretty long distance since its low voltage

MDB1029 · Post by **MDB1029** » Tue Feb 17, 2015 7:45 pm

lnevo wrote:You can have the dimming leads from the dimming expansion travel a pretty long distance since its low voltage

You are saying to run led leads from the dimming ports the 40ft from the RA unit to the DT, right? Wouldn't the leads lose voltage or amperage running that far? The leads on there right now are 22 awg and Mike at Rapid couldn't give me much info on what type of wire to use. He suggested using maybe 20 or 18 and i would assume solid but after looking for wire at Lowes i learned i know nothing about wire other than guage. There was some 18g solid "sprinkler wire" and 18 g solid "thermostat wire" would either of those work or would you be able to point me in the right direction there?

rimai · Post by **rimai** » Tue Feb 17, 2015 9:53 pm

22 gauge is fine.
Even 24 gauge, which is what most CAT5 cables have is fine.
You are only running signal through it and a CAT5 cable has 4 pairs, but you just need 2

MDB1029 · Post by **MDB1029** » Tue Feb 17, 2015 10:15 pm

rimai wrote:22 gauge is fine.
Even 24 gauge, which is what most CAT5 cables have is fine.
You are only running signal through it and a CAT5 cable has 4 pairs, but you just need 2

Ever have that glass shattering moment? When i read this comment, I had one. I have been WAY over-thinking this. I have been thinking I would need to have my psu and drivers near my sump and run the power leads all the way to the fixtures. So i feel really dumb now but am glad It finally clicked.

jegillis · Post by **jegillis** » Wed Feb 18, 2015 2:19 pm

A 40 ft run with 24 gauge wire (cat 5) on the dimming ports amounts to a 0.1 volt drop assuming if I remember correctly .05 amps from the dimming ports.

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