Can you put two neutrals under one screw on a panel neutral bar?

No. NEC 2023 408.41 requires each grounded conductor, meaning each neutral, to terminate on an individual terminal within the panelboard. Two neutrals under one screw is a code violation every time, and it has been since the 2002 cycle. Equipment grounding conductors are a different story: most neutral and ground bars are listed for two or even three EGCs of the same size under one screw, and that is fine when the panel label says so.

Why the rule exists

The neutral is a current-carrying conductor. If you need to isolate one circuit, you lift its neutral. When two neutrals share a screw, lifting one loosens the other, and on a multiwire branch circuit that momentary open neutral puts series 240 volts across the two legs. Loads on the lighter leg see well over 120 volts and electronics die instantly. The rule protects the next person working the panel as much as it protects the equipment.

What inspectors look for

Doubled neutrals are one of the most common panel write-ups on service upgrades and finals. The fix costs nothing: nearly every loaded panel has open terminals, so move one conductor to an empty hole and torque it to the label value. If the bar is genuinely full, add a listed add-on neutral bar from the panel manufacturer, not a generic bar drilled into the can.

Neutral and ground under one screw

Also a violation, even in a main service panel where neutrals and grounds land on the same bar. The neutral still needs its own hole per 408.41, and mixing a ground under the same screw defeats the one-per-terminal rule. Grounds with grounds per the listing, neutrals alone, always.

Field notes

Older Zinsco and Federal Pacific bars were never listed for doubled conductors of any kind, so treat anything you find in them as suspect. When you tidy a panel, re-torque what you touch and note it. A neutral bar with one conductor per screw, dressed and torqued, tells the inspector the rest of the work is probably right too.