Joe is correct, but the underlying rules are a frequent source of confusion.
Basically, the 415 limits apply per employer or controlled group, but the surprise emanates from the rule that the 403b participant is considered to be the employer for 415 purposes only. So when that employee holds a 50% or greater interest in his separate firm, the contributions to both plans must be aggregated. In addition, the monitoring of this limit now falls to the 403b sponsor, so employees that have side businesses can expect to be questioned about the status and contributions to that business, and the 403b contributions are then subject to reduction to fall under the 49,500 limit.
The following explains this and more:
https://www.mysavingsatwork.com/taxexem ... rticle.pdf