Burned Square D CP2540G Bus Duct Repair

The Problem

An electrical contractor contacted us with a problem. He had recently had three Westinghouse tap boxes fabricated for a job at a manufacturing facility. Unfortunately, there were problems with the tap boxes. Each tap box was supposed to have a different length neck to accommodate the space available. Additionally, one of the tap box's bus bars was loose.

Fortunately, the contractor still had time before the scheduled electrical shut­down of his customer's manufacturing facility. This is was the situation when we were contacted.

The Bus Duct

The bus duct installed in the plant was Westinghouse Lifeline series. An older busway series introduced by Westinghouse in the mid 1940s. The installed Lifeline series was 600­amp, 3­wire (three bus bars, no neutral bar) copper.

The normal tap box for the Westinghouse Lifeline busway is a plug­in style. The tap box sits on top of the duct and jumpers drop into the joint. For this job, because of the space constraints, the customer needed end cable tap boxes. The tap boxes attaching to the end of the duct. This would allow the necks to be different lengths and then the tap boxes to be staggered upon install.

Solution

We were able to take the existing parts of the tap boxes and build three new tap boxes. We extended the necks to the lengths required by the customer. We needed to re­build the tap boxes because there was not enough neck material, or bus bar to extend the necks. We replaced the enclosures so that the necks could be assembled in the correct position, and so that all three tap boxes would have a similar appearance.

As for the tap box with the loose bus bar. It tuned out that an incorrect insulator had been used that was not properly securing the bus bar. Probably, an insulator from another bus duct series.

These tap boxes will be used to start three different runs of Westinghouse's Lifeline plug-in busway.