DC Electrical Setup

[oakbarn]

I am familar with 110 vac and handle that well. 240, I hire an electrician. But I need to "learn" DC.

I have some new valves that are12 vdc or 24 v dc

I have two new transformers,
12 vdc @ 4.5 amps
24 vdc # 6.5 amps

The power is L N and Ground.

Those would be the 110 vac supply
I have a single 15 amp circuit supplying the power

L = Hot = Black 14 ga
N = Neutral = White 14 ga
Ground is Ground = Bare Copper

I have one circuit for both transformers and they are the only load on the circuit.

On the DC output thhere are 3 terminals
NC - +

I am running a red wire from the + of the 12vdc to a relay then to the valve
I am running a blue wire from the + of the 24vdc to a relay then to the valve

- are all green wire tied togather and run to the valves as well.

Do I also need to attach the Ground to the - green wire?

I also assume that if any DC wire crosses a temp probe wire, it should be at 90 degrees and then ran away from the probe wire. I am planning on putting my Temp probe twisted pairs in metal conduit.

[JonW]

The answer to this depends on what kind of relays you are using. If they are SSR's that are driven directly from the low current BCS 5V outputs, then you're fine with not hooking the ground together. However, if the relays are a 12V relay board or similar that is powered from one of the power supplies, but triggered from the BCS, then yes, you need to tie the grounds together.