Bangor Hydro Electric Company

Much of the problems and damage from power quality issues can be prevented if you have the right protection for your equipment. For example, look for "battery backup" and "ride-through" protection features when purchasing new home appliances.

Topics

Grounding

Battery Back-Up Units

Wiring

Dedicated Circuits

Isolation Transformers

Voltage Regulators

Power Line Conditioners

Grounding - Proper grounding is the first step in making your equipment less susceptible to damage. A good ground is also essential to the safe and reliable operation of any piece of electrical equipment.

Electrical grounding ensures that if there is ever a short on a piece of electrical equipment, current will flow through the ground system and trip a breaker or blow a fuse, thereby providing protection from injury or electrocution. Grounding also is the primary path through which a Transient Voltage Surge Suppressor dissipates energy from an electrical transient.

Equally important is that grounds for electric, cable TV, phone, and other utility services be bonded together at the service entrance. This is a requirement of the National Electric Code. If you have a ground rod and the cable or phone lines are not bonded to it, contact the appropriate company and ask them to come check your system. In most instances, it is their responsibility to bond these to your grounding system.

For more information about grounding, click here.

Transient Voltage Surge Suppressors (TVSS) - These provide protection from extremely fast disturbances (millionths of a second to a few milliseconds) in voltage. These are the simplest and most common form of equipment protection. They do not provide protection from voltage sags, voltage swells, noise, outages, or harmonics.

Every piece of electrical equipment is subject to transients. To what extent you protect the equipment will depend on the type of problems it might be susceptible to and how valuable it is to you. Obviously, an old coffee maker does not warrant the same level of protection as your expensive new personal computer.

Effective transient protection requires the coordination of large capacity devices at your service entrance along with progressively lower voltage clamping devices inside. Transient Voltage Surge Suppressors (TVSS) placed inside also protect your equipment from any internally generated transients.

There are three main categories of TVSS: Service Entrance, frequently referred to as "whole house", Sub-Panel/Distribution Panel, and Sub-Panel/Receptacle. These three types should be used together to provide a complete protection system.

And make sure to also put protection on all incoming phone, data, and cable TV lines. For equipment with power and data ports, such as FAX machines, answering machines or cable TVs, use protective devices which provide protection for both the power and data ports. If you have an outside antenna or satellite dish, all leads coming from these should be protected as well.

Battery Backup Units - These are designed to provide a supply of regulated voltage for a period of time after power failure. These devices fall into two basic categories: standby power supplies (SPS) and uninterruptible power supplies (UPS). Standby power supplies use the incoming utility power and only switch over to battery if power is interrupted. There is a transfer time (usually a few milliseconds) for the SPS to sense an outage and switch to batteries. UPS units, on the other hand, provide a continuous source of "conditioned" power through an inverter or converter. There is no transfer time when an outage occurs. These devices are the more expensive of the two battery backup units. SPS and UPS sometimes also come with noise suppression and transient protection built in.

Wiring - Most buildings are originally constructed with sufficient wiring to handle the electrical load at the time of construction. However, as your electrical needs change and your usage increases, you may experience problems due to inadequate wiring. A circuit breaker that trips on a regular basis or lights that dim or flicker are indications you may have an electrical problem that needs to be evaluated by a licensed electrician.

Dedicated Circuits - You may want to consider placing sensitive equipment on a separate circuit that supplies power only to that device. Computers and other electronic equipment should not be plugged into the same circuit that provides power to a large motor-driven appliances, such as an air conditioner, or equipment that has high start-up current, such as photocopiers and laser printers. Always consult a licensed electrician before making any modifications to your electrical circuitry.

Isolation Transformers - These are generally installed to reduce electrical noise to sensitive electronics.

Voltage Regulators - These are designed to provide a constant voltage output in the event of voltage sags or swells on the incoming line.

Power Line Conditioners - Typical conditioners provide voltage regulation along with transient voltage surge suppression and noise reduction. An all in one package which is generally fairly expensive.