Generator load side wiring

[rookie4now]

The attached photo came on a generator we're installing. It is a table for wire ampacity and it shows that the 125 breaker on the generator would require2/0 wire. Why? Is that a mandatory label?

 

[texie]

The attached photo came on a generator we're installing. It is a table for wire ampacity and it shows that the 125 breaker on the generator would require2/0 wire. Why? Is that a mandatory label?

There must be more info to indicate if this AL or CU?
If AL, it would seem that this is correct as 1/0 AL @ 75 degree is 120 amp and 2/0 AL @ 75 degree is 130 amp.

 

[Smart $]

The attached photo came on a generator we're installing. It is a table for wire ampacity and it shows that the 125 breaker on the generator would require2/0 wire. Why? Is that a mandatory label?

While many would/will say 110.3(B) applies...

(B) Installation and Use. Listed or labeled equipment
shall be installed and used in accordance with any instructions
included in the listing or labeling.

... 110.2 is the overriding requirement IMO.

110.2 Approval. The conductors and equipment required or
permitted by this Code shall be acceptable only if approved.

Informational Note: See 90.7, Examination of Equipment​

for Safety, and 110.3, Examination, Identification, Installation,​

and Use of Equipment. See definitions of Approved,​

Identified, Labeled, and Listed.​