Electrical Connection Methods in Wet Well Design
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Electrical Connection Methods in Wet Well Design
In pump station system design, it is common for some aspects of the electrical design to be given less than adequate attention. This article focuses on electrical connection methods. Specifically, the designer must consider the connection of electrical equipment inside the underground wet well to the above-ground electrical control system. In wastewater pump stations, the wet well is classified as a hazardous area, due to the potential build-up of explosive gas. Egress of electrical cables from the wet well can be tricky business, since there are a variety of ways to run the cables and make electrical connections. Romtec Utilities has devised three methods for electrical connection; direct connection, above-ground junction box and below-ground junction box.
Hazardous Area Classification for Pumping Stations
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One of the first, (and most important consideration) in system design is area classification. Area classification, will at a minimum, dictate the required components necessary to meet code. NFPA 820 along with NEC defines the classifications for Wastewater Treatment and Collection Facilities. It is important to note NFPA 820 covers “Pumping Stations” which is a broad term and is inclusive of most waste water pump systems. For this reason NFPA is pertinent in nearly all in ground waste water pumping systems.
In general, residential collection systems serving 5 or less dwelling units are “Unclassified” and thus fire and explosion hazard is not applicable. NEC still applies for general guidance in these systems. For systems larger than 5 residential units sewers are categorized by usage type. Read more
