2-2-2-4 SER, or copper, for attached garage subpanel?

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Old 08-30-20, 09:57 AM
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2-2-2-4 SER, or copper, for attached garage subpanel?

I'm dragging my feet on this project but just need to get it done, and at this point it comes down to whether I should use SER or go the extra hassle and cost of copper...

I will be running a feeder through 20' of finished (but currently cut open) basement ceiling, perpendicular to joists, to a subpanel in my attached garage so that I can run 30 - 45 amps of woodworking equipment (now) plus window or mini split AC (next summer). The other day I purchased 35' of 6-3 NM, which is good to, as I understand it, 55 amps. But now I feel like I should have purchased 2-2-2-4 SER. Why not overkill it now and not have to ever open the ceiling and walls again? Larger service would also allow a future electric car to charge while operating dust collector and either a saw or the CNC (<30 amps between the two) as well as allowing the window or mini split AC to run, would it not?

As I have read about SER, it sounds like there are some concerns with using it. However, it seems to pretty much be standard for subpanels and 100% safe so long as it is torqued correctly and NO-OX-ID applied at both termination points (if copper). Is this true, or should I really try to do copper for this?

I thought that THHN inside conduit was out of the question because about 14' of the feeder run is perpendicular to the 2x8 joist direction, so holes will be needed (I believe I can have up tp 1/3 of that 8" distance drilled out per building code). But I discovered that I may be able to pull #2 copper THHN conductors through a flexible conduit such as Sealtite or similar.

What should I do? Go get 2-2-2-4 SER, install it just as I would have installed the 6-3 NM (exact same install, right?), and call it a day? Or should I pursue copper?
 
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Old 08-30-20, 02:51 PM
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SER comes in copper and aluminum. 2-2-2-4 Aluminum SER is 90A and is about $1.40ft. Comparable copper for 85A is 4-4-4-4 and is about $4.00ft. Antioxidant is suggested for Al, not for Cu.
Pick your poison.
 
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