Back-up systems for when the power goes out

Power outages are rare and usually short here, but grid-provided electricity isn’t completely consistent and reliable under all circumstances. Here’s a quick guide to the world of power quality problems and actions individuals and businesses can take to minimize negative effects.

Transient power quality issues that don’t result in outages include voltage variations (sags, swells and spikes), poor current frequency and problems with power factor. (Power factor is technically complex and is usually only relevant to businesses that use many electrical motors.) These problems only last for millise...