He is 27. She is 18.

It was a teacher and student relationship that became sexual.

Outside of the education world, their after-hours affair might be accepted.

In the classroom, though, the rules are different.

A teacher with authority over a student legally old enough for a sexual relationship can be jailed on a felony charge, even if the situation was consensual.

That is what happened Friday to Eric Thomas Helms, a West Ashley High School faculty member. He was charged with sexual battery with a student.

In South Carolina, 16 is the age of consent. Teachers who have sex with students who are 15 and younger face felony rape charges.

The legal situation that Helms faces is a result of a state law that became effective in 2010 making it a felony punishable by up to five years in prison for a teacher to have sex with a student, regardless of whether the student is of age and the relationship is consensual.

Laura Hudson, who was instrumental in creation of the law, said the action was taken at the request of the state Department of Education out of concern for teachers in authority over a student where a sexual relationship is happening.

“It’s been an increasing problem,” said Hudson, executive director of the S.C. Crime Victims Council.

“Even if they were to rise to the age of 20, it would still be illegal,” Hudson said.

On Friday night, Helms’ bail was set at $5,000 and he was ordered to have no contact with the student and told to stay at least a block away from her house and the school.

Charleston County Sheriff’s Detective Lauren Ryan said Helms had no criminal record and had been completely cooperative in the investigation.

Helms told Magistrate Alvin Blidgen that he had submitted his resignation to the school. Helms had nothing else to say, other than when he answered questions from Blidgen about whether he understood the court proceedings.

The school website still lists Helms as a faculty member but provides no other information. A district spokesman said Thursday that Helms is no longer employed at the school. A parent who did not want to be identified said Helms was a school junior varsity soccer coach.

Ryan said she could provide no further information about Helms’ role at the school. She said Helms was arrested Friday. No one else involved in the case attended the brief hearing.

His student was participating in the Teacher Cadet program at the school as a teaching assistant for Helms. Students can become teaching assistants and help with classroom tasks if they do not already have an assigned class during certain hours and receive approval.

The arrest of Helms, a resident of Riser Street in Charleston, is a result of information that was provided to the Sheriff’s Office.

According to police and court records, the sexual relationship between Helms and the student was consensual, mutual and no drugs or alcohol were involved.

An affidavit states that between Jan. 1 and March 26, the couple had sexual intercourse “several times” at Helms’ apartment. The student told investigators that the relationship started in January when she became a teaching assistant in Helms’ classroom.

In January, Helms “asked me if I wanted to hang out one day and I said sure” and “it kept going from there,” the affidavit states. The relationship originated from Helms’ text messages to the student in reference to a school-sponsored club meeting, according to court records.

Detectives don’t believe Helms had sexual relationships with any other students.