Utility Safety Q & A Articles

Q: I work for a small utility and am new to my safety role. Recently I have been wading through the Federal Motor Carrier Safety Regulations (FMCSR) in an attempt to understand my responsibilities with regard to testing CDL drivers. Can you briefly explain these responsibilities?

A: FMCSR 391.31 requires the employer to ensure a driver is competent by means of road testing. The FMCSR allows a valid commercial driver’s license as evidence of competency (see FMCSR 391.33). If the employer accepts the evidence of the driver’s competency, the employer does not have to road test the driver. Rule 391.33(c) allows the employer to conduct a road test if they so choose even if the driver has a current license and certificate of competency. If the employer intends for the driver to haul double or triple trailers, they are required to conduct a road test. The road test criteria are listed in FMCSR 391.31(c).

Q: I’ve been reading ASTM 855, IEEE 1048 and the National Electrical Code, and I’m a little confused by the practice of grounding through a switch. Can you help me better understand this?

A: In transmission/distribution applications, there is no issue with grounding through a switch. To explain, we always have to ask whether the issue is grounding through (in the path) a switch or grounding (by way of closing) a switch. The application may sound the same, but it depends on which standard you read. Our subject matter experts think the confusion lies in the well-known NEC rules, which require permanent installations to have a connection-free path for the ground electrode conductor at the service entrance of an electrical system. According to the code, grounds – except in some specialty connections – cannot be disconnected through operation of a switch or breaker contact. ASTM 855 is an equipment manufacturer's standard that has no application to utility practices in the field other than being used as a guide for shop construction, sizing, rating and assembly of personal protective grounds. IEEE 1048 does address the value of having the grounding switches closed when de-energizing a system for work; that ground switch is a very low-resistance path to earth at the feeder or transmission bus source that will lower fault current in an accidental or inadvertent energizing of the source. The ground switch in the station is also a path to ground that will divide and help reduce the amount of induction current on a circuit. Closing the switch can help reduce induction current at a work location, depending on how far apart the work location and the ground switch are.