A modular, non-metallic enclosure with a first enclosure having an open end between first and second side panels and a second enclosure having an open end between third and fourth side panels. At the open end of the first enclosure, the first and second side panels each include a guide rail having a male guiderail member and a female guiderail channel. At the open end of the second enclosure, the third and fourth side panels each include a guide rail having a male guiderail member and a female guiderail channel. The male guiderail member/female guiderail channel of the first sidewall are configured to engage with the opposite of the male guiderail member/female guiderail channel of the third side wall. The male guiderail member/female guiderail channel of the second sidewall are configured to engage with the opposite of the male guiderail member/female guiderail channel of the fourth side panel.