Technically, as the code is written, there's no reason not to use aluminum for nearly everything. True, there are a few exceptions, such as certain grounding conductors where the NEC specifies theat aluminum shall NOT be used, but those are the exceptions.
Indeed, the aluminum wire makes will tell you that aluminum is every bit as reliable as copper.
Yea, right. The wire makers leave out a few details:
They neglect to mention the change they made in the alloy used in the late 70's, to address issues that - they still claim - were caused by poor installation.
They also neglect to point out that they don't make the stuff smaller than #6 anymore. So, while there's no rule against using all aluminum to wire a house, lots of luck finding that #12 Romex in aluminum.
The same paradox exists as to the use of anti-oxidant compounds. The wire makers say there is no more, or less, reason to coat aluminum than there is copper. The NECA standard seems to assume that you will use it when working with aluminum, but doesn't specifically tell you to use it. The NEC is silent on the issue.
This is -yet again - where 'trade practice' varies from what the rule books say. Personally, I'll stick with tradition.
