Who must carry it in New Jersey
Every employer not covered by a federal program must insure its workers' compensation obligations from the first employee, or qualify as a self-insurer.
Who counts as an employee
Part-time and casual employees count, and corporate officers are employees. The label on the paycheck does not settle it: New Jersey applies its own employee test, and a worker who fails it is an employee for workers' compensation no matter what the contract says.
Owners, officers and LLC members
Sole proprietors and partners without employees need not cover themselves; LLC members and officers are covered unless the company has no other employees and elects otherwise. The election is made on the policy and affects both coverage and premium, so decide it before the policy is bound rather than at audit.
The day you hire
CoverMatch quotes workers' compensation from the first employee, with pay-as-you-go billing through most payroll companies where a carrier offers it, so the policy can start the week you hire without a large deposit. Add the policy to your wallet and the live certificate is ready for the general contractor or client who asks for proof.
If you go without
Failing to carry coverage is a disorderly persons offence with penalties per day, and the uninsured employer is personally liable for benefits. The specific amounts and procedures are in the statute and on the agency page linked above; they change, and the licensed agent who reviewed this page checks them on each update.