overlapping vs. switching neutrals

[cvirgil]

In a automatic transfer switch application, the generator is a seperately dervied system at 480V. The transfer switch installed is a 4 pole with an overlapping neutral.

Questions:

1. Can an overlapping neutal be used with a separately derived system where overlapping is only momentarily (make before break)

2. What are the pros and cons of using swicthing vs. overlapping.

 

[RonShap]

This article has some good information

http://bg.ecmweb.com/ar/electric_switching_neutral_whats/

 

[rbulsara]

Overlapping "is" part of the switching, where it momentarily overlaps but source of neural gets switched. There is no difference between the two.

Or in other words when a neutral is 'switched' it is always done via overlapping neutral. This is to avoid system being left without grounding even for a moment.