scjohn,
I have to apologize; it was inappropriate for me to moralize this discussion. We all take it as a given that doing less work, or installing smaller wire than is _agreed_ is not appropriate.
The real issue is: One of the promised materials is far in excess of what the customer needs. Materials prices have changed suddenly and unexpectedly, such that delivering the promised goods at the promised price means that you don't make your deserved profit.
There are two questions that this discussions can help answer: 1) Would installing smaller wire result in a safe and proper installation. 2) How can you pitch this change to the customer, so that they will agree to the change and both of you will come away from the deal reasonably satisfied.
The answer to 1) seems to be yes.
I wish I had better customer relations skills so that I could help you with 2)
I personally think that there are innumerable ways that one can 'oversize' in order to 'increase safety', which are not at all really necessary nor which actually increase safety. Engineers oversized things whenever they are not spending their own money! It has nothing to do with being in the pockets of suppliers, or trying to cheat anyone. It is simply 'bigger is better' combined with 'someone else's money'.
-Jon
