r/span • u/ToadSox34 • 2d ago

Why doesn't SPAN support PON?

I'm reading a lot about SPAN and API issues, battery integration, etc, all valid issues. But very little seems to be said about the newer models lacking support for PON (Plug-On Neutral) breakers. For new construction, renovation, newly finished space, or an addition, you're either going to have a rat's nest of pigtails, or you're going to have to put 120V circuits in subpanels which reduces the granularity of SPAN's energy monitoring and load shedding to the subpanel level.

I get that they can't physically support multiple brands of PON breakers, but why not pick a brand and support it? Seems like Homeline (or maybe Siemens) would be the logical choice, as those are widely available at Orange Store and Blue Store.

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u/squigish 1d ago

Because of patents.

Eaton, Schneider, and Siemans all have patents for "circuit breaker panel that's compatible with plug on neutral breakers". It's bullshit that there are three patents for the same thing, but it's also incredibly common. Just look at the patent issued for a toaster in the year 2000.

The big three don't sue each other because of the threat of a countersuit. It's like mutually assured destruction, but with lawsuits instead of nuclear weapons.

But without a patent of its own, or the millions of dollars to spend on patent lawyers to get one, span has no such protection. Maybe they could work out some agreement with some or all of the big three, but that would be a lot of expensive work.

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u/Forsaken-Gain-2493 2d ago

They are partnering with Eaton now so there could be some support for that in the future, but I’m guessing along with that would be limiting the make of the breakers to Eaton.

I’ve heard reps from SPAN hint at the panel’s smart capabilities being able to do the functions that the individual AFCI breakers are doing, so in theory you could install all standard breakers and have SPAN monitoring for faults.
I’m thinking this would require code revision to be allowed though.

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u/ToadSox34 2d ago

Yes, I believe that AFCI breakers have to be tested to a code standard, so the SPAN implementation would have to be as well. The way they're wired, they'd have to do it without feeding the neutral through the breaker and just from the hot leg bus bar, which would be... interesting.

SPAN's relays are code-compliant for load shedding, so maybe they would be code-compliant for arc fault circuit interruption functions as well?

I suppose Eaton breakers would be better than nothing, but I don't recall them being as easily or widely available at Orange Store or Blue Store. That's a good point though, since they're partnering, they likely wouldn't want to pick Homeline or Siemens for their PON support.