731. A Partition with Many Openings

Shabbos 16:16

If a partition’s open area exceeds its closed area, it is not considered a partition at all. If the open area equals the closed area, one may carry within the enclosure so long as none of the openings exceeds ten cubits in width (about 15’). This is because an opening up to ten cubits in width is considered an entrance. If the opening is surrounded by an entry frame, it does not invalidate the partition even if it when wider than ten cubits so long as the open areas do not exceed the closed areas.

Shabbos 16:17                    

The above halacha applies when the openings of the partition are three handbreadths or wider (9”+). If the openings are each smaller than three handbreadths, the partition is valid even if the open space exceeds the closed space. This is because an opening smaller than three handbreadths is considered as if it were closed up.