Refining IPB Design

March 14, 2023

Isolated-Phase Bus (IPB) systems are vital in transferring bulk electricity through the grid. For decades, IPBs have been centered around the original designs from General Electric (GE) and Westinghouse, which led the industry. Now, improvements to insulators, mountings, and housings have elevated the model, making them even more reliable. 

IPBs transfer a power plant’s heavy amperage (between 6,000 to 45,000) among the generator’s output bushings and the main step-up (GSU) transformer. Because of their invaluable role, it is crucial that IPBs provide an extreme amount of consistency to ensure power plants function without outages, downtime, or equipment damage.

Now, enhancements made to IPBs aimed to improve the original design include refinements to IPB insulators, insulator mountings, the continuous housing assembly, and more. New IPBs have great -strength and hold high-creep porcelain insulators that can provide better resistance against tracking to the ground. 

While most IPBs require costly space heaters and specialized pressurization systems to control condensation, the new versions have specific dew point ratings, which help to reduce impending failures associated with wet weather.

Other IPB designs require opening the mounting or cover plate before they can be inspected or cleaned. This tedious step increases the risk of damage or incorrect re-installation. The newer IPBs have fewer required insulators per linear span and have a built-in “window” that offers an easy way to visually inspect the interior. 

New IPB models also eliminate the need for a separate ground bus, as the enclosure acts as its own ground plane. Without voltage potential, IPBs can fail due to inter-sectional arcing. Plant engineers and maintenance managers have a duty to safeguard personnel or equipment faults. 

IPBs have never been more reliable thanks to the new-and-improved design. 


J&P Electrical is a full-service electrical supply company. At J&P, we source contractors, end-users, and supply houses with new surplus, quality reconditioned, and obsolete electrical equipment. We also purchase a wide range of heavy industrial electrical equipment such as bus plugs, bus duct, transformers, circuit breakers, fuses, and switchboards. Call us at 877-844-5514 for assistance.  

Written by the digital marketing team at Creative Programs & Systems: 

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