I would like to connect 6 gauge aluminum wire to 12 gauge copper wire. Is an aluminum splicer/reducer suitable for this in the USA? An example is the Morris 90612. It is a rectangular aluminum block with holes on the ends to accept the wires that are then held down by screws. It of course requires antioxidant and insulation, probably rubber and vinyl electrical tape.
There is much discussion about Al to Cu connections here and elsewhere on the web, but the common solutions either don't handle 6 gauge or are in my opinion overpriced for the task. Split bolts are another option, but I wanted to avoid the awkward shape, especially when it comes to insulating.
I think the item I am a referring to has been mentioned here as something like a mechanical lug. It almost seems like a slam-dunk that it is suitable since it is AL9CU dual rated, but there are many things that might not be obvious in the rules. In the Q&A section at one of the big box store websites, a customer service rep said another brand nearly identical and also AL9CU was not rated for this. The only reason I could think of is if the wires are inserted too far and become intermixed. Some versions are said to isolate the two sides.
This is to make a pigtail to connect the 6 gauge aluminum to a 20 amp breaker with an 8 gauge maximum. The splice would be in the breaker panel, which has plenty of open space. The old 40 amp breaker is beyond the required maximum overcurrent protection for a new heat pump.
I could avoid the whole aluminum to copper thing if thinner aluminum wire were readily available for the pigtail. I don't want to go to the effort of trying to replace the wire all the way out to the heat pump.
Sorry so long-winded, but I think of what might be misunderstood and add detail. Thanks for reading and all the past answers I read.
EDIT: Morris tech support told me not to use 90612 for this. Details in comments below.