N.C. Gen. Stat. § 150B-29

(1) In all contested cases, irrelevant, immaterial and unduly repetitious evidence shall be excluded. Except as otherwise provided, the rules of evidence as applied in the trial division of the General Court of Justice shall be followed; but, when evidence is not reasonably available under the rules to show relevant facts, then the most reliable and substantial evidence available shall be admitted. On the judge's own motion, an administrative law judge may exclude evidence that is inadmissible under this section. The party with the burden of proof in a contested case must establish the facts required by G.S. 150B-23(a) by a preponderance of the evidence. It shall not be necessary for a party or his attorney to object at the hearing to evidence in order to preserve the right to object to its consideration by the administrative law judge in making a decision or by the court on judicial review.

(2) Evidence in a contested case, including records and documents, shall be offered and made a part of the record. Factual information or evidence not made a part of the record shall not be considered in the determination of the case, except as permitted under G.S. 150B-30. Documentary evidence may be received in the form of a copy or excerpt or may be incorporated by reference, if the materials so incorporated are available for examination by the parties. Upon timely request, a party shall be given an opportunity to compare the copy with the original if available.