Generator Connection Bar Insulation After a Bridging Fault

Client Background

A critical facility suffered a phase to phase fault on the connection bar between a standby generator and its MV switchgear. Investigation found the fault was initiated by an animal bridging two bare bars inside the enclosure.

Project Challenge

Insulate the connection bar system on a facility that cannot take an extended outage, using a method that also handles the bolted terminations at each end.

Customer Pain Points

• Bare bar inside an enclosure that could not be made animal proof
• A critical facility with a very short permitted outage
• Bolted terminations at the generator and switchgear ends that a tube cannot cover
• The facility's maintenance policy requiring joint inspection to remain possible

Our Solution

S1 busbar insulation tube on the straight bar sections and S1-B molded covers on the bolted terminations at each end. The S1 family carries UL 224 recognition under file E341796 which satisfied the facility's equipment approval policy.

Manufacturing Process

Tube supplied cut to the measured bar lengths. Covers tooled from a dimensioned survey of the actual terminations carried out during a planned maintenance window.

Supply Chain Coordination

Survey to first article to production ran inside the facility's planned maintenance cycle so the retrofit needed only one short outage.

Quality Control

Per lot testing plus a fit check of the first article covers on the actual terminations before production.

Final Result

The retrofit was completed inside a single short outage. Both generator sets have since been insulated to the same standard and the facility added insulated bar to its standard for all new MV connections.

Customer Benefit

A recurring failure mode eliminated on a facility that could not afford the outage a full switchboard rebuild would have needed.