service upgrade: tandem and arc fault breakers


San Diego,CA
Hey all, I'm doing a service upgrade to 200amp. I bought a 40 circuit 20 space semi flush meter panel combo. Will I get called if I install tandem breakers because of the" replacement use only code". Also are inspectors looking for arc fault breakers in service upgrades? I've been doing commercial industrial for a while so I'm a little out of the loop of residential standards.


Staff member
You are good to go with a 20/40 panel, you can fill it with mini breakers.

As far as the AFCIs I think that will vary area to area.


Senior Member
New Jersey
The "replacement use only code" deals with non CTL (circuit total limiting) panels prior to 1965 that allowed tandem breakers without the requirement in 408.54. These breakers so marked should only be used in panels that are not CTL rated.

408.54 Maximum Number of Overcurrent Devices. A panelboard shall be provided with physical means to prevent the installation of more overcurrent devices than that number for which the panelboard was designed, rated, and listed. For the purposes of this section, a 2-pole circuit breaker or fusible switch shall be considered two overcurrent devices; a 3-pole circuit breaker or fusible switch shall be considered three overcurrent devices.