Generators - Critical Issues

Backup generators are not the simplest systems to install and maintain. A tremendous amount of attention must be paid to the details of location, size, connectivity, fuel storage, automatic transfer switching, regular and preventative maintenance, and many other items.

Let's briefly summarize some of these issues. Generators are large, noisy, and require special ventilation. Their placement inside a facility must consider these constraints. They must be located where they are accessible to maintenance personnel and where fuel lines can safely connect to them. In most cases there is significant current harmonic distortion from the type of loads powered by the generator. It is recommended that the generator be 10% to 20% larger than the maximum load, or load growth, to take into account the harmonic distortion.

Transfer switches allow the generator's power to feed into the normal distribution system. These switches are vital, since you cannot alter the power source if they fail. They should always include some form of manual override, with clearly accessible directions on how to operate the override.

Liquid fuel (oil or gasoline) is usually stored in two separate containers. One is the main storage tank and the other is a day tank. The day tank is small and in close proximity to the generator. When the fuel level in the day tank gets low, more is pumped in from the main tank. Make sure that this pump is on the backup power system. If not, the day tank is all the fuel available.

Ensure that all critical systems, such as special lighting, HVAC, and fire systems, are on the backup power. Remember as well that backup generators require significant investment of money, planning, testing, training, and regular upkeep.