Knob-and-tube wiring, aluminum branch circuit wiring, fuse-based service, Federal Pacific Stab-Lok panels and Zinsco panels are the five electrical systems most likely to stop a property submission cold. Many carriers decline buildings that still have them or write them only with conditions, and Rainbow's lessor's risk only (LRO) program doesn't write a location with any of the five. For agents in California and New York, where so much of the commercial building stock went up before 1950, that makes the electrical panel one of the first questions to ask a landlord client, not the last.
Call it checking the bones before you list the house. Below: why underwriters flag each system, how to spot it before an inspector does, why CA and NY see it most, and what a building owner can do to get back in the market.
Because each one carries a known fire or failure pattern, and property underwriting prices the building's ability to not burn down. A landlord's policy also carries liability for tenants and visitors, so an electrical fire is both a property loss and a potential injury claim. The common thread across all five systems: age, no ground or weak overcurrent protection, and decades of DIY changes nobody documented.
Ask before you quote. Most of these systems are visible to anyone who opens a panel door or walks the basement, and an inspection report that finds one after binding is a much harder conversation than a question on the first call.
Both states have a deep stock of buildings old enough to still hide original wiring, and that's exactly the stock agents tend to see in LRO and mixed-use submissions.
California: in San Francisco, most homes built before 1950, and a few as late as 1960, used knob-and-tube wiring, according to a March 2025 ABC7 report on Bay Area owners facing declines and cancellations. That story was about homeowners, but the same pre-war buildings line commercial corridors, with shops downstairs and apartments above. Add the state's tight property market, and a K&T finding can push an owner toward costlier last-resort options while the fix gets done.
New York: New York City's pre-war walk-ups and mixed-use buildings, and the older downtown blocks in cities upstate, share the same profile: century-old structures rewired a floor or a unit at a time, if at all. For a landlord with retail on the ground floor and offices or apartments above, a single original circuit in one unit is enough to make the building ineligible.
The appetite question isn't state-specific, though. A 1920s building in Texas or Florida raises the same flag. CA and NY simply put it on more of your desk.
Our commercial real estate (LRO) program is built for landlords, including older buildings, mixed-use and multi-tenant properties, with up to 20 buildings and up to $15M TIV per building. But on wiring, the line is firm. No insured location can contain:
Here's the underwriting view that matters for your E&O: on our LRO policy, these conditions are written as warranties, not just eligibility questions. A warranty that turns out to be untrue can put coverage itself at risk, not only the premium. So "I think the panel was replaced" isn't good enough. Confirm it, document it, and if the answer is unclear, ask our underwriters at underwriting@userainbow.com before you bind.
Electrical age matters too. A system that has never been updated can be a problem on age alone, even if the brand on the panel is fine, so have the date of the last electrical update ready with the submission. Rainbow orders an inspection on every building we write, which is one more reason to know the answer before the inspector does.
Fix it, prove it, then resubmit. The usual paths, which a licensed electrician should scope:
Then gather the proof: invoices, permits with final inspection sign-off, and photos of the new panel labels. If the rewire is phased across tenant spaces, track which units are done, because every insured location has to be clear before the building fits.
One more conversation worth having: when an older building is rewired after a loss rather than before one, code upgrades can add real cost. That's where ordinance or law coverage earns its spot on the quote, depending on the policy form and limits.
Sometimes the timing is the whole story: an owner has a signed electrician's contract and a start date, but the policy renews next week. Don't paper over it. Tell us exactly what's in the building today and what's scheduled, and let underwriting decide what's possible. A clean, honest submission is faster than a declined one, and much faster than a coverage dispute after a fire.
Before you send it, check Rainbow's product availability by state to confirm LRO is open where the building sits.
Rainbow's LRO program gives you appetite for older, mixed-use and multi-tenant buildings, with clear rules you can check on the first call. Placing commercial property in California or New York? Get appointed with Rainbow and quote your next landlord in minutes.
Often not without conditions. Many property carriers decline commercial buildings with live knob-and-tube wiring or require proof of a rewire first, because it has no ground, its insulation degrades with age and it can't handle modern loads. Rainbow's LRO program doesn't write locations with knob-and-tube, so documented replacement is the usual path back.
If only part of a building has been rewired, list exactly which spaces still have original circuits and confirm eligibility with underwriting before you submit.
It's difficult. Federal Pacific Stab-Lok panels are a common decline trigger because CPSC testing found some of the breakers failed UL calibration tests, even though the agency closed its 1983 investigation without a recall. Rainbow's LRO program excludes locations with FPE Stab-Lok panels or breakers, so the fix is replacing the panel and documenting it.
Ask for a photo of every panel label in the building, including tenant subpanels, before you quote.
Yes, for most property underwriters. Zinsco panels, including those sold as Zinsco-Sylvania or GTE-Sylvania, have a known flaw where breaker connections to the aluminum bus bar loosen, arc and overheat, sometimes fusing so the breaker can't trip. Rainbow's LRO program doesn't write locations with these panels until they're replaced and documented.
It depends on the carrier and the repair. Aluminum branch circuit wiring from roughly 1965 to the mid-1970s raises fire risk at its connections; the CPSC found pre-1972 aluminum-wired homes were 55 times more likely to have outlets reach fire hazard conditions. Rainbow's LRO program excludes locations with aluminum branch circuit wiring.
The CPSC treats full copper replacement as the permanent fix, with COPALUM and AlumiConn connectors as accepted repair methods. Twist-on pigtails and CO/ALR devices count as temporary at best.
Both states have large stocks of pre-war buildings that were never fully rewired. In San Francisco, most homes built before 1950 used knob-and-tube, and the same era of construction lines commercial corridors there. New York City's pre-war walk-ups and mixed-use buildings share that profile, so agents in both states should ask about wiring on every older submission.
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