Redundant / HA Connection - power vulnerability.

I am planning to move to work from home, but job involves monitoring some important 'assets' over the Internet. I'm lucky enough to have Virgin, Openreach (and soon Cityfibre) to different sides of the property, so I could order a second connection for some redundancy. 4G / 5G is also strong locally and is my current 'bodge' failover. I also have a solar / battery system that can be set to work in a power cut (unlike many!) so power isnt an issue.
My question is however, how 'localised' a power cut would knock out all these networks as power is lost to street cabs/ towers? Would the whole city (unlikely) need to go down, or does every street corner cab now need mains (with no meaningful UPS) or its lights out? Mobile towers I dont think have any protection these days?
Thoughts? Experiences?

OR used to supply BBU's (basically tiny UPS devices) with their ONTs up until 2018 when some ill-advised Ofcom guidance intended to guarantee emergency service access actually allowed them to stop giving them out.

If the ONT being powered was to survive a power cut, one would assume that all other network equipment involved in the connection would be in place too, so I'd assume that an OR connection should survive a power cut, although I've no idea for how long.

I'm with HeyBroadband, as that's all that's currently available to me, and I've already had multi-hour downtime apparently due to power issues that haven't affected me personally.

I have my ONT and router an a UPS that I bought, along with my PC. Seems like a no-brainer. Not sure how Cityfibre operate, but given that they're a reseller, I'd hope they have better redundancy than HB.

Good point re the 'legacy' baby UPSs - I used to work on FTTC cabs and a few in 'sensitive' areas did indeed have battery banks in them, but I have no clues on FTTP ones. I guess it's info OR may not be keen to share!

The Openreach FTTP network is completely passive between the head-end exchange and client premises, so no power required other than for a few 'subtended headend' (a mini OLT) to provide service where clients are a really long way from the serving head-end exchange.

Excellent news - thanks!

Virgin = HFC/RFoG areas. No cabinet backup. Power goes out to cab. No broadband, TV or phone for you. Zero autonomy.

Openreach, ADSL + FTTP - are exchange based (although typically in 80% off of cases not the same exchange. FTTP goes to larger parent/headend exchanges). Either way BT exchanges will have the best backup of all solutions, with diesel generator backups in place. Up to days (and possibly longer) of autonomy. Exceptional exceptions for long line FTTP which uses remote OLTs in cabs.

Openreach FTTC - you are reliant on cabinet batteries which may be missing or aged. A few hours autonomy at best.

Cityfibre - runs back to a FEX (fibre exchange). They all have diesel generator backup to my knowledge. Runtime is not widely known, but expect autonomy to be a few days.

Masts - a variable feast. Some have diesel generator backup, but by no means all. Autonomy could otherwise be a few hours up to whenever the batteries give out.

Useful, thanks. Do (almost?) ALL phone masts have at least a bit of battery backup in a cabinet somewhere? (Generators I assume I could spot via exhausts etc - havent seen any locally!)

In reply to a post by warwickwater:

I am planning to move to work from home, but job involves monitoring some important 'assets' over the Internet. I'm lucky enough to have Virgin, Openreach (and soon Cityfibre) to different sides of the property

Are you talking about Openreach FTTP or FTTC?

FTTP doesn't go via street cabinets at all, so no worries about power there - it's completely passive all the way back to the head-end exchange (where there will likely be diesel backup). FTTC *does* rely on powered cabinets, which typically have some level of battery backup, but if you're unlucky the batteries are worn out and give up almost immediately.

I believe that Cityfibre FTTP is also passive all the way to their POPs (aka "fibre exchanges" or "FEXs")

Some mobile towers have power backup; some don't.

Virgin HFC has powered street cabinets, so for the best protection against power outages (as well as best performance) I'd take Openreach FTTP and Cityfibre.

However, it's possible that Cityfibre will be using Openreach's ducts, so arguably you'd get better protection against physical network damage by taking Virgin plus one of the others.

In reply to a post by warwickwater:

Useful, thanks. Do (almost?) ALL phone masts have at least a bit of battery backup in a cabinet somewhere?

No, sadly. The huge towers with large container sized boxes at the base, vary, some might, most don't. However there are a significant amount of streetworks poles, with tiny cabinets on footpaths, no space for batteries or generators. Talking 10,000+ masts for one network grouping (e.g. CTIL, or MBNL).