Where to tie negatives together for Elk M1 and P124


Active Member
I'm adding a P124 power supply to my system and am seeing all the topics recommending you tie the negatives together. Is the best way to accomplish this to just run a wire from the VAUX negative of the M1 to the negative on the P124 board?
Connect a negative terminal on the M1 to the negative terminal on the P124.
Hate to be dense, but which negative terminal on the M1 are you talking about. The OP mentioned the negative on the VAUX. Is that appropriate or should it be something else?

If you have 3, it doesn't matter if I daisy-chain them versus homerun to the Main elk, right?

I (will) have 2 power supplies in a 2ndary location, with the main elk being the 3rd. Would be simpler to run one wire from the main to one of the secondaries.
Yes. It was recommended to me by Rfdesq and other Cocooners. It stems from the need for the supplies to share a common reference.

Sometimes its hard to see the need for something unless you consider an extreme example. Grab a magical voltmeter and put its positive lead on the positive terminal of a 12VDC supply. Now connect its negative lead to the negative terminal of a 12VDC supply here in Montreal (I told you it was magical). Are you 100% certain it'll read 12 volts? If two supplies don't share a common ground, there's no certainty about voltage levels.
As this wire is for a voltage reference, I assume a single 24 AWG cat 5 conductor is adequate. No? How much current does this wire carry?
Now that's a good question! Theoretically, there's no potental difference (i.e. 0V) between the two negative terminals so there's no current flow. Ahem, theoretically. Now what happens if something does go screwy and there is a current flow?

Hope for the best but plan for the worst ... I used the same wire gauge throughout (16 AWG).
So, just to make sure, I am connecting a single wire from the VAUX NEG terminal on the M1 to the negative output terminal on the P624. Is that correct??