Nema 5-20 Female to Nema 5-15 Male Power Adapter for UPS: safe?

I bought a large UPS for my server and didn't realize it comes with a NEMA 5-20 plug. We're in a residential setting and don't have those outlets. I see Nema 5-15/20 Female to Nema 5-15 Male Power Adapters but it seems not safe to me, if the device is expecting a dedicated 20 amp circuit. This is the UPS: https://www.cdw.com/product/cyberpower-smart-app-online-ups-series-ol2200rtxl2u-ups-1.8-kw-2200-v/3059881?pfm=srh is it safe to use an adapter and plug it into a residential circuit?

I wouldn't do it - you can plug a standard 15A plug into a 20A socket, but going through an adapter to "downgrade" from 20A to 15A seems incredibly unwise, at the very least.

It's akin to using the grounding/non-grounding adapter to utilize a three-prong plug in an old-style two-prong outlet.

Either:

• get a UPS with the proper plug for your outlet, or
• get an electrician to rewire the outlet and associated circuit breaker to a 20A (presuming the wall wiring can handle it)

I'd lay heavy odds CyberPower will not honor their attached equipment guarantee if you've done something janky to get it connected to the wall :)

There is no problem with safety, as long as the adapter is of good quality. The 5-15 outlet will be fused 15 A, which is about the same as the maximum current draw for this UPS. It depends on the characteristics of the UPS and the total power consumption of your servers, if the fuse will blow or not, so it's not the best solution. Doesn't cost much to try tho'. It might be that the UPS a bit of an overkill for your server size, since it is designed for a higher current than what you have available.