Maquis
Well-Known Member
- First Name
- Dave
- Joined
- Dec 21, 2020
- Threads
- 30
- Messages
- 4,446
- Reaction score
- 6,157
- Location
- Illinois
- Vehicles
- 2021 Mach E4X, 2023 Lightning Lariat ER
They are not prohibited by the NEC, even the 2020. What the code does require is that the breakers installed in a panel be listed for that panel. The label on the panel will list what breakers are allowed in a panel and the panel manufacturer has no incentive to list competitor's breakers for use in their panel.Hmm. They wouldn't manufacture and sell 1/2 height breakers if they weren't to code, although I suppose the recent code could prohibit them and some older townships haven't moved to the latest. I know that I had to put some 1/2 sized breakers in before finally upgrading my panel, but that was in the 2005-2008 timeframe. I put them on 15A circuits to free up room for a full-sized 40A A/C breaker.
Some manufacturers do not make tandem breakers, so people will install breakers from other manufacturers because they physically fit. Basically today, all 1" breakers will fit in competitor's panels: Siemens, GE, Cutler-Hammer BR, and Square-D Homeline. But that would violate the listing and thus the NEC.
To further complicate matters, some panels will only accept tandems in certain positions and have a physical rejection feature on the bus or mounting rail to preclude their installation in an unallowed location.
There is also the issue of "classified vs. unclassified" tandems, but that's a whole other problem!
Sponsored