wwhitney
Senior Member
- Location
- Berkeley, CA
- Occupation
- Retired
An academic question about the nuances of the wording in the first paragraph of 705.12(B) (2017; in 2020 the language moved to 705.12). Which of the following, if any, is exempt from the requirements of 705.12(B), because it is not "distribution equipment . . . fed simultaneously by a primary source(s) of electricity and one or more other power source(s) and . . . capable of supplying multiple branch circuits or feeders"? In all cases there are three breakers of equal size, one for the utility supply, one for a PV/ESS, and one for a feeder to a load panel.
1) A 2 space MB panel with 100A MB and quad 100A/100A breaker.
2) A 6 space MLO panel with (3) double pole 100A breakers.
3) An 8 space 200A MB panel with (2) double pole 4 position 200A breakers.
For (1), I don't know if such equipment exists, but suppose it does; I wanted an example that unarguably does not fit the quoted language.
For (2), someone could come along and replace the 100A double pole breaker with a quad breaker; does that mean it is "capable of supply multiple branch circuits or feeders?" If so, there's no way to qualify it under 705.12(B)(2)(3); if you want that topology, you need to reconfigure it as a feeder splice rather than use a panelboard. [E.g. (3) separate 100A disconnects with a gutter; apparently the wire-type feeder is safer than a single enclosure with a busbar? (ironic)]
Likewise for (3), some one could come along and replace the 4 position 200A breaker with (2) 2 position 125A breakers (generally). That would create an actual chance of the bus being overloaded. So I guess it is prohibited by 705.12(B)(2)(3).
Cheers, Wayne
1) A 2 space MB panel with 100A MB and quad 100A/100A breaker.
2) A 6 space MLO panel with (3) double pole 100A breakers.
3) An 8 space 200A MB panel with (2) double pole 4 position 200A breakers.
For (1), I don't know if such equipment exists, but suppose it does; I wanted an example that unarguably does not fit the quoted language.
For (2), someone could come along and replace the 100A double pole breaker with a quad breaker; does that mean it is "capable of supply multiple branch circuits or feeders?" If so, there's no way to qualify it under 705.12(B)(2)(3); if you want that topology, you need to reconfigure it as a feeder splice rather than use a panelboard. [E.g. (3) separate 100A disconnects with a gutter; apparently the wire-type feeder is safer than a single enclosure with a busbar? (ironic)]
Likewise for (3), some one could come along and replace the 4 position 200A breaker with (2) 2 position 125A breakers (generally). That would create an actual chance of the bus being overloaded. So I guess it is prohibited by 705.12(B)(2)(3).
Cheers, Wayne