Semicolon use
A semicolon following an independent clause [a complete sentence] signals that what follows is also an independent clause whose meaning is of equal importance to the first. Joining two clauses with a semicolon alone is appropriate only when the clauses are closely related and the relationship is clear. If they are not closely related, you probably should make them separate sentences. RULE: Although an independent clause following a semicolon is essentially a complete sentence, it never begins with a capital letter. Unlike a coordinating conjunction [and, but, for, or, nor, so, yet), a conjunctive adverb [however, nevertheless, accordingly, besides, indeed, similarly, then, thus, therefore, that is and others, or a transitional expression ["in fact" or "for example"] cannot be used with a comma to join two independent clauses. Conjunctive adverbs and transitional expressions require a stronger mark of punctuation: a semicolon [I wasn't busy;however, I did not have time to play golf.] 2) "When items in a series contain commas, readers may have difficulty deciding which commas separate parts of the series and which belong within the items. To avoid confusion, put semicolons between elements in a series when one or more contain other punctuation.[Confusing: "I interviewed Debbie Rios, the attorney, Rhonda Marron, the accountant, and the financial director." Edited: "I interviewed Debbie Rios, the attorney; Rhonda Marron, the accountant; and the financial director."] (The Longman Writer's Companion).
source: http://www.drgrammar.org/faqs/#14