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There are three distribution arrester types commonly used to protect overhead distribution equipment from the damaging effects of overvoltage. IEEE C62.11 defines Normal Duty (ND) and Heavy Duty (HD) classes by their ability to withstand certain current impulse levels. The third, Heavy Duty Riser is a type, or variation, of the HD classification and utilizes a larger diameter Metal Oxide Varistor (MOV) disc.

1. Once all safety concerns have been addressed, attach the Kelly bar adapter and installing tool assembly to the Kelly bar on the installing truck.

As with most mechanical devices, CHANCE® anchor-installing tools periodically require maintenance checks to ensure peak performance.

When comparing different arrester designs, it is important to understand how the arrester was built to correctly evaluate the amount of protection it will provide. The IEEE C62.11 standard covers two types of Metal Oxide Varistor (MOV) distribution arresters that are available today, internally gapped and gapless. These arresters might look identical from the outside, but the different internal module design affects how the arrester protects voltage sensitive equipment.

1. Choose anchor site carefully. Rock anchors will only perform effectively in solid competent rock (Class 0 Soil).

The safety procedures described below are the basic steps and necessary equipment linemen will employ when replacing an insulator from an aerial lift truck on a tangent structure with rubber gloves.

When considering an underground enclosure specifics matters. It is important to take load ratings into consideration. For confidence in selecting the right load ratings it is recommended to choose out of the two verified ratings, the ANSI/SCTE77 or the AASHTO H20. When determining the best load rating consider the enclosures intended use.

ANSI/SCTE77

The ANSI rating is best for non-deliberate traffic areas. These enclosures are placed where direct wheel impact is not likely or anywhere that traffic is not intended. The area may include grassy areas, sidewalks, highway berms, light pole bases, highway median strips and parking lots. These enclosures are designed to handle only occasional, non-intentional traffic.

AASHTO

This load rating is intended for direct traffic areas, such as highway or roadway lanes, intersections and parking lots. These enclosures are situated directly in a wheel path and are designed for anywhere that traffic will directly impact the enclosure.

If you have questions about ANSI-SCTE or any other applications for enclosures, please call your Hubbell representative. We'd be happy to work with you in specifying your underground enclosure applications.

KNOWING THE DIFFERENCE

It pays to know the difference between the two enclosure ratings. AASHTO H20 rated enclosures come with a heftier price tag due to their heavy duty design. AASHTO enclosure covers are made from unique material, such as cast iron, in order to handle continuous heavy loading. It is advantageous to know the specific rating needed for your job in order to avoid unneeded substantially high prices and to ensure enclosure longevity.

Four years, several prototypes and thousands of installations later, Hubbell has satisfied Alliant Energy’s need for a stronger neutral clevis.

"Proper alignment" and "down pressure" are simple phrases to summarize proper anchor installation technique. The Power Installed Screw Anchor (PISA®) wrench transmits torque from the digger’s Kelly bar to the anchor hub. Note: The anchor rod only has to be of sufficient diameter to support the guy load.

Underground enclosures, commonly call handholes, pits, or vaults, come in a variety of shapes and sizes and house critical electrical, telecommunications, gas and water service connections. While each underground enclosure application may be different, there are a few installation fundamentals that should be followed to minimize field damage and help insure many years of use.