NON insulated Ground wire

[Joseph M. Whitt]

When the NEC is addressing line surges it is addressing the switching of grids which can cause a surge of voltage of several thousand volts that have been known to last for several sine waves. Lightning striking a substation or transmission lines can cause surges on our services that last as long as the visible flash that surge protectors such as the plug-in strip type cannot stop. This type of surge will need a surge arrester installed at the service in order to be of benefit to the user although the plug-in type will afford some protection

Smaller surges such as motors in AC units, air handlers, well pumps and the like is not what is being addressed by the NEC. These surges will be very short lived, in the nanosecond time period and the voltage level will be less than a thousand volts. These surges are similar to spikes and the plug-in surge strips are designed to stop these.

It is high voltage types of line surges that have someone using uncategorized testing equipment getting hurt. All voltage testers used at a service should be a category IV at 600 volts. Meters that have no category rating should never be used for anything larger than electronic circuits. This information can be found in NFPA 70E.

[Larry D. Kage]

Thanks, Mike.