I know I’ve purchased many for other Sonos speakers (non-Sonos power cables, that is) on Amazon. Mostly for shortening myself, although options are greater now than when I originally purchased.
 

Have you looked at other non-Sonos options? It is just a power cables, after all, it just needs to be tested, and carry the correct amperage/voltage with the correct cable terminations. And I don’t recall that there’s anything unusual about them.

Thanks Bruce! I’ve heard that I would void my Sonos warranty by using a different power cable. I’d love to avoid that if possible. 

If I was up in a warranty situation, I’ll have kept the original cables, just in case. OTOH, it really is just carrying power, if it is UL listed (here in the states), then it should be fine. Other jurisdictions may have other testing agencies, but any ‘reputable’ cable should be fine. I’ve often purchased Flexson, but there are others these days. The reason I like Flexson (a UK company) is they tend to (at least to my mind) over engineer everything. Which means it won’t fail. I’ve used their power cables, and several speaker stands and mounts. 

However, I wouldn’t try to claim against Sonos if the power cord failed, and ruined the unit, either…clearly, it wasn’t Sonos’ fault, but the power cord I purchased and used. 
 

OTOH, I’ve never, in the last 20 years, heard of that happening, either.

I keep coming back to this, I wonder if I’m trying to make up excuses?

I consider it essentially the same as plugging in a Sonos power cord into an extension cord, which I’ve done many, many times. In fact, my current setup has this occurring. At least until I get an electrician in to install some new additional ‘close to the ceiling’ power outlets….

Thank you for the quick responses on this, Bruce! I’ll do some research into your recommendations and go from there, there. Really appreciate it! 

Have you checked Flexson, ​@cfc0d3r ?

For UK they do this one: https://www.flexson.com/10388753-5m-power-cable-for-sonos-era-100-and-300-ray-arc-sub-gen-3-sub-mini-amp-beam-play-base-play5-gen-2 but they may well do these for US market too. 

I’ve often ordered Flexson either directly from Flexson’s own website, or via Amazon (faster shipping, when they have what I want in stock) here in the US. I think at one point I picked up some stands at Best Buy, but their stocking is variable, IMHO. I don’t go there very frequently anymore, but they might have extensions for Era speakers.