1966 ITE residential service equipment withstand ratings

[Oldfilament]

I'm looking for information on the withstand (Bracing) ratings for a 600 amp & a 400 amp ITE single phase, fused, residential service main with meter stacks. The service was installed in 1966. The AIC from the new utility transformer is 39k. The service is still in good condition but all labels have been painted over or are missing. All installed 125 amp feeder breakers are rated 10k. I understand that newer Siemens breakers with a higher AIC (42K) can be retrofitted but the issue of the bus bracing is in question. If anyone has any info regarding bracing ratings of these boards it would be very helpful indeed.

 

[jim dungar]

Bus bracing is not usually a concern for panel boards where the bus is supported for its entire length. Bracing is definitely a concern where bus is unsupported as in switch boards, motor control centers, and some meter stacks.

Manufacturers and UL changed their SCA methodology/ thought process/ testing around 1985. Prior to that manufacturers used terms just about any way they wanted and series rating were not common. Integrated Equipment Ratings were often mentioned rather than SCA ratings. This was the time that the term 'withstand' started to fall into disuse.