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Hi everyone! 

First post and an electrical question.  I know, talk to a qualified electrician, and I will.  Seems like there are a lot of knowledgeable people here and I wanted to hear your opinions.

I want to power 3 Avalon 741’s on a single 220v line.  There is a 10ga ALUMINUM wire run maybe 40-50 ft to the main panel.  Nothing else on this line.

This place was built in the early 70’s and aluminum is what I have to work with.  It’s in a mostly finished basement and I don’t have a way to run a new line.

Capacity charts tell me 10ga AL is good for 25A.  I’m planning on putting a 20A breaker in the panel and a L6-20r on the other end.  I have a PDU that has 15A breakers for each of the 4 outlets.  Should be enough power for these three machines.

I understand most of the issues with aluminum is at connections so I will have to find breaker and outlet rated for use with aluminum.

Service entry wire is usually aluminum, right?  I know the A/C, fridge, freezers, etc. have been used in this house for decades, but I’m just worried about this continuous 24/7 load.

What do you think, good to go or will I have a BBQ?



 

BBQ! I'd get a fishtape and some copper and repull!

Fuck no. AL oxidizes instantly, and the oxide will cause a nice hot connection if it is not airtight. Nice and hot plus 25a@10g=warm yule log fire in your house walls.

BTW for a 30 amp car charger I ran 8 gauge copper wire and it still gets a bit warm. 10g would be stupid.

Ha! Not just a no, but a Fuck No.  love it.

I wasn't feeling real good about it anyway.  Drywall ceiling and the joists run the opposite direction I want to go, not sure I can fish it.  I'll come up with something.

Your 30A car charger warms up an 8ga?   I would have thought 10ga CU (AL is out the window for me now) for my 20a circuit would have been more than enough.

What size copper would you pull for 20a circuit?

Thanks

I would call an electrician. A good one. I work with DC systems with somewhat... large wires where O and OO gauge wire can get warm. But as a rule the more power you pull the weirder things can get.

Per my little black book, in North America most codes call for a minimum of 12ga copper. I'd prefer 10ga and 6-20 receptacles will be happy accepting it.

^^^ What he said!  And (safely) Mine On!  8)

I suppose this isn't a toaster oven that's on intermittently for 10 minutes at a time.  When I meet with the electrician instead of just pointing and saying I want 20a there, I'll explain that I'm going to be kicking the crap out of the circuit and to build some margin in.

I don't have time for an insurance claim, or...um, death.

Thanks for being the voice of reason.

Just wanted to check, I know you said your PDU has 15 amp breakers for each of the 4 outlets, but what is it's total rating for amps for the PDU, and for each branch?

I would hate to see you get the wiring set and everything else just to find out you need additional set up materials.

Also is that the only AL left in your house? I love finding little left over surprises like that, my century house is full of them.

Good luck

I don't have it in front of me for the model, but it's one of those HP PDU's that came out of a server rack.  You can pick them up for $50 or so on ebay.

I think it's good for 24A total input and there are 4 c20 outlets with a 15A each.  I've ordered 12ga c20 to c13 cables, one for each miner.

The house is mostly the original AL from the early 70's.  There was a kitchen/sunroom remodel 25ish years ago that was done in copper.  Not sure how they pulled that off, I was away at school when that project was happening.  I know what you mean about century homes, several of my friends have homes that are close to a century and I'm the guy they call when they need help with something.   What's that woven cloth covered wire called?  good times.

Sounds like the same ones I picked up, or atleast similar. I just remember hunting eBay, and finding so many that were close bit not quite right. Well good luck and happy mining.