Do generator transfer switches fall under the dedicated space requirements of 110.26?

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110.26 (F) specifically calls out switchboards, panelboards, distribution boards and motor control centers. Would an automatic generator transfer switch which is NOT the service disconnect (supplies power to one sub-panel only) fall under this category also or were the four items listed to the exclusion of any other type of panel, controller, junction box, etc.?
 

eprice

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110.26 (F) specifically calls out switchboards, panelboards, distribution boards and motor control centers. Would an automatic generator transfer switch which is NOT the service disconnect (supplies power to one sub-panel only) fall under this category also or were the four items listed to the exclusion of any other type of panel, controller, junction box, etc.?

Look at the definition of "Panelboard" in Article 100. It seems to me that the transfer switch would fall within that definition.

Edit: well, maybe not. On second read, it seems like the presence of overcurrent devices is necessary for it to be a panelboard.
 

eprice

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There isn't a definition in article 100 for "distribution board". Would the transfer switch be on of those?
 

charlie b

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The NEC does not explicitly say this, but it has always been my opinion that 110.26(F) is based on allowing room for the future installation of new conduits. It is likely that panelboards, switchboards, and MCCs will someday get new circuits, and need new conduits, so space is being reserved for that purpose. Once you install an ATS, there will be no future need for additional conduits. That is why, IMHO, the NEC only explicitly names three components.
 
It seems to me that since the types of things mentioned in 110.26(F) have to do with providing power distribution to a number of circuits and loads in other locations and that the reasoning behind leaving room to get to these things has more to do with getting conduits and/or wiring to those pieces of equipment in the future. Does this make any sense?
 

jumper

Senior Member
The NEC does not explicitly say this, but it has always been my opinion that 110.26(F) is based on allowing room for the future installation of new conduits. It is likely that panelboards, switchboards, and MCCs will someday get new circuits, and need new conduits, so space is being reserved for that purpose. Once you install an ATS, there will be no future need for additional conduits. That is why, IMHO, the NEC only explicitly names three components.

:thumbsup:
 
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