Does a driver have to record hours at a non-motor carrier?

Yes. The driver must log time working for a second employer, even if it is a non-driving position. It must be noted as on-duty/non-driving. Sec. 395.8(a) says the driver must record their "duty status for each 24 hour period.” Part of that duty status is all on-duty time. The definition of on-duty time in 395.2 includes, “Performing any compensated work for a person who is not a motor carrier.” Therefore, all compensated work, whether for another motor carrier or not, must be included on the log as on-duty time, and goes against the available hours of the driver.