PORTLAND, Maine — The Maine Supreme Judicial Court considered Tuesday whether a court-ordered Public Utilities Commission study about the safety of Central Maine Power Co.’s smart meters at the homes of about 615,000 customers met the legal standard laid out by the justices three years ago.

The justices ordered in July 2012 that the PUC determine whether CMP’s smart meters pose “a credible threat to the health and safety” of its customers. The commissioners concluded in December that they do not.

Advocates opposed to smart meters appealed the commission’s finding arguing that it came to the wrong conclusion.

The state’s high court is not expected to decide whether the meters are safe or not, but whether or not the PUC properly conducted the study and based its conclusion on the evidence presented.

Bruce A. McGlauflin, the attorney for Ed Friedman and the Maine Coalition to Stop Smart Meters, argued Tuesday that the PUC’s conclusion was contrary to the evidence presented to commissioners. That evidence included the testimony of 65 witnesses who described the adverse health conditions suffered after exposure to smart meter radiation as well as a reduction in symptoms after avoiding exposure, he said in his brief.

PUC attorney Jorden P. McColman argued Tuesday that the commissioners’ conclusion was “based entirely on substantial evidence in the record.” That included “field studies showing compliance with FCC regulations, the fact that no other government organization has found that the low-level [radio frequency] from smart meters is harmful to humans, and that the scientific studies in the record overwhelmingly show that there is no conclusive evidence that low-level RF emissions are harmful to human health,” he said in his brief.

The Federal Communication Commission sets guidelines for RF radiation from all devices such as cellphones, Wi-Fi and smart meters, according to a previously published report. The study conducted by the PUC showed the “exposure would be approximately 500 times below the FCC standard,” the brief filed by the PUC’s attorneys said.

Chief Justice Leigh I. Saufley and Justice Jeffrey Hjelm said Tuesday that the federal rules concerning smart meters, currently under review by the FCC, would prevent the PUC from setting stricter standards in Maine.

There is no timetable under which the justices must issue a decision.