We would not contact your employer unless we required specific information from them, normally in circumstances where you have failed to comply with any of our requests and/or if you have missed any of your agreed payments.
If you have missed payments then your Trustee may instruct your employer to deduct your payment directly from your salary via an Income Payment Order granted by the court.
The only other way your employer could find out about your sequestration is via the ROI (or the Edinburgh Gazette, should your case be advertised).