The NEC has been migrating away from using the grounded conductor (usually a neutral) as an equipment ground for quite some time. The general rule is once you pass the service disconnect, equipment grounds and grounded conductors are to be separated an the grounded conductor should not come into contact with a grounded enclosure.
The CH catalog for their spa disconnect shows two factory installed bus bars.
Good to know.
Maybe the disconnect i got this time was missing neutral bar, and since i don't do that many of them i just over looked it.
