A comma splice occurs when what follows a comma could stand as a sentence on its own. ‘Tim was an excellent surfer, he often visited the beaches in Cornwall’ is a comma splice. Instead of the comma, you have three options:
- add a joining word or term, such as ‘and’
- add a full stop and a capital letter
- add a semicolon.
Your decision will partly depend on whether the connection between the first clause and the second is lost if you use a full stop to separate them. If you want to make it clear that the second clause follows in meaning from the first, expanding or explaining it, use ‘and’ or a semicolon.