110.3(B) mfr instructions

[pipe_bender]

If manufacturers instructions require a copper branch circuit, is that part of the code per 110.3(B)?
How do I know what parts of mfr instructions are part of the code?
Say I have a tank water heater replacement, existing circuit is AL to the water heater,
I was planning on setting a jbox on the wall and switching to copper for the whip.
The part of the branch circuit to the water heater would be copper but not the entire circuit..
FYI I plan to go with my plan either way because it would be a pain to pull a new cable, and I think its safe, but wanted to see what you experts think:

 

[roger]

I agree and have done the same thing. What if the branch circuit starts in a loadcenter with an AL buss?

IMO a copper pigtail to the unit is sufficient.

 

[charlie b]

How do I know what parts of mfr instructions are part of the code?

First of all, I agree with Roger.

But my answer to this question is that mfr instructions are never part of the code. What is part of the code is that we must comply with mfr instructions that are part of the listing. What is open to some debate is whether anything and everything that appears in any document provided by the mfr was, in fact, included in the instructions that the mfr gave to the lab that conducted the tests upon which the listing was granted. That is generally not knowable to designers or installers.

One viewpoint I have encountered is that, not having any details of the testing setup, we must, by default, consider every word in the owner's manual to be an absolute requirement. I don’t agree, at least not as a general principle. As a trivial counter example, if a dishwasher manufacturer's owner's manual recommends a particular brand of detergent, the homeowner would not be violating code by using a different brand.

In your case, I suspect that the tests associated with the process of obtaining the water heater's listing did include a branch circuit with copper wires.

 

[jim dungar]

In your case, I suspect that the tests associated with the process of obtaining the water heater's listing did include a branch circuit with copper wires.

But aluminum cannot be prohibited in the entire feed from the utility.
At best the manufacturer can prohibit it at their terminals.

 

[don_resqcapt19]

But my answer to this question is that mfr instructions are never part of the code. What is part of the code is that we must comply with mfr instructions that are part of the listing. What is open to some debate is whether anything and everything that appears in any document provided by the mfr was, in fact, included in the instructions that the mfr gave to the lab that conducted the tests upon which the listing was granted. That is generally not knowable to designers or installers.

It is my opinion that if the instruction in not found in the UL Guide Information, it is not a 110.3(B) instruction. However UL has stated many times that anything provided by the manufacturer is 110.3(B). I do not agree with that.