THC connections on a Miller 625 Extream

Need help finding which wires to connect to on a Miller 625 Extream for the THC? It isn’t with the remote plug on the front. So the wires are color coded different than what was shown on the THC setup. Any help would be appreciated.

I plan on hooking up the black wire to the torch and the red wire to the work. I found this wiring diagram in the OM.

The torch is negative and the work/ground is positive. Most wiring systems the red is positive and the black is negative.

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Good call I fixed the diagram.


Did you get it to work? I have a Miller 375 X-treme that I wired up for the original crossfire but I just ordered the THC kit so I’ll need wire that in. I’m curious if you have any tips.


Did you get your xtreme 375 wired up yet? if so, can you share some info on it, thanks.

I bookmarked this link that should help you. Miller 375x wiring I’m still on the fence about THC for my XL table but I think peer pressure is pushing me over and will need to wire up my 375 as well. :grinning:

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Right on! Perfect! Thanks ! On it now!

We did ours was easy to do and the wiring is very easy. The quality of the cut also improves

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The purse strings are loosening even as I read this :thinking::rofl:

Ive checked all the connections and keep getting this error code, any ideas?

reach out to Langmuir support email…
try to go through it all again…not just the connestions…but the actual sequence

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Even though you’ve checked all the wiring maybe try to swap the polarity of the leads coming out of your Miller.

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that might’ve been it, testing it out now

yep, was my issue, got it


I have a 625 . Just follow the instructions. I had a problem with the wiring torch was negative and table was positive.