Practical considerations using aluminum wire

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granroth

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Gilbert, AZ
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Software Engineer
I am building a guest house situated 200 ft from the main house. It will have a nominal 60A service. I am planning on using aluminum wire for the first time and want to ensure that I'm not missing some bits.

Note that while I am not an electrician, this work is being done under a permit and will be inspected. I just want to do it right the first time and not have any callbacks.

Here's my plan.

I start with a Square D QO 60A Circuit Breaker (QO260CP) in my main panel. The power is transmitted over 200ft of 2-2-4-6 Aluminum Mobile Home Feeder Cable in 1-1/2" PVC conduit buried at 18".

The cable will terminate at the guest house in Square D QO 100A QOM1 Frame Main Breaker (QOM100VHCP) in a new Square D QO 125A 24-Space 34-Circuit Indoor Main Lug Plug-On Neutral Load Center (QO124L125PGC).

(Also, there will be 2 x 8ft buried ground rods at least 6ft apart, connected via 4AWG copper since the ground is not very conductive around here)

Okay, before I even say anything else, is there anything above that jumps out as a red flag? Or even a "this is better?"

Some assumptions:
  • I'm converting the Main Lug sub panel to have the Main Breaker since I will need a shut-off switch anyway, it being an out building
  • Everything is Square D QO since that apparently has a good reputation
  • That load center is 24 spaces and is plug-on neutral, so it fits the main criteria. I would prefer surface mount, if I could find one

Given all that, my questions are all about the connection details. Do I just plug the aluminum wire directly into the two breakers and bus bars like copper or should I be doing something special? Maybe use NOALOX? I've also heard about using "compression" fittings on the end of the wires since they have embedded NOALOX plus create a more secure connection for life... but the ones I've seen are all lugs, and it's not clear to me if those could work in this scenario. Are there compression fittings that aren't lugs?

So yeah, let me know anything that I said wrong; anything I should be looking at; anything I should be doing.
 

Little Bill

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