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Minnesota Department of Labor and Industry Minnesota Department of Labor and Industry Powered by Google


Temporary service equipment


March 17, 1974

The following requirements of the National Electrical Code (NEC) and Minnesota Rules apply to all installations of service equipment, including temporary services.

Under NEC Section 384-14, a panelboard with more than 10 percent of its overcurrent devices rated 30 amperes or less, which supply circuits having a neutral conductor, is defined as a lighting and appliance panelboard. That would include almost all of the panelboards installed for temporary services.

NEC Section 384-16 requires lighting and appliance branch-circuit panelboards to be protected on the supply side by not more than two main overcurrent devices. Where a plug-in back-fed circuit breaker or fusible switch serves as the main, NEC Section 384-16(f) requires it to be secured in place by an additional clamping device furnished by the panelboard manufacturer for that purpose. Only clamping devices and the specific circuit breakers or fusible switches identified on the label in the enclosure are acceptable. Main-lug only panelboards without the required main overcurrent device arrangement are not permitted to be used as service equipment.

Listed Power Outlets consisting of factory assemblies of receptacle outlets and overcurrent devices in an enclosure, generally weatherproof, are not panelboards and are not subject to the above requirements, but are permitted to be used as service equipment only when listed and marked "Suitable for use as service equipment for (temporary sites, mobile homes, marinas, or boatyards)." Power Outlets without a service equipment marking must be supplied from suitable service equipment.

All equipment used as service equipment, including that for temporary services, must be listed and labeled "Suitable for Use as Service Equipment", in accordance with NEC Section 230-70(c) and Minnesota Rules Part 3800.3620."

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