UPS lighting?

[T i m]

Hi all,

Just thinking out loud and talking of power cuts ... what would the rules say if I took the feed from the CU for the downstairs lighting (6A) cct to a single 13A socket and then brought the ends of the lighting ring into a suitable junction box beside it and a short length of flex with a 13A plug (with a 6A fuse?) and back into the socket (so downstairs lights back on as usual).

Then, if I wanted, I could fit a suitable (1000VA?) and earthed UPS into the system which could easily be disconnected / bypassed and with no chance of anything getting crossed up (like trying to supply the national grid from my UPS)? ;-)

I ask because I already have a APC UPS doing nothing and as we only have gas fires, gas cooker and low energy lighting, we would be able to cope (for a while anyway) in the event of a power cut?

Cheers, T i m

[Martin Brown]

It is easier just to plug a LED mains lamp into an existing UPS socket or have an LED torch with 5M resistor bridging the switch so that you can still find it in the pitch dark. These are quite neat with the glow in the dark plastic case - you can see by it when dark adapted.

Search for "Glo torch" on eBay and they ocassionally come up for sale.

No connection with the seller - just very impressed with the product. Incredibly useful if you live somewhere that is pitch dark or go camping in the wilds and need to find a torch in total darkness.

I have a couple of emergency lights with 5Ah lead acid batteries but they are old school inverter types that drive small fluoro tubes.

Today you would go for LED lighting for maximum efficiency.

[T i m]

But it won't be as 'good / nice' as having all the downstairs (at least) lights stay on in the event of a power cut?

I have a large leisure and several other batteries on hand if I wanted to jury ring up additional lighting but I thought, for what wouldn't be much work ... something more automatic / subtle, especially when I wasn't here and it was just the Mrs and our daughter.

That was the effect I was going for.

That's what I have in many locations, those of CFL so I have no worry about the load and therefore should get quite a good run-time.

Cheers, T i m

[Tim Watts]

You could just run the lighting circuit through the UPS on a permanant basis - there is no risk at all of it backfeeding out its supply terminals.

[T i m]

Yes, I allowed for that as an option but this was more about the rules and any 'gotchas' I may not have considered rather than anything else. ;-)

Like, the UPS's I have are 'smart' / online and they wouldn't need to be for this role. eg, The lights aren't going to care about any glitches as the UPS switches over from straight through to 'On battery'. However, would a fluro, CF or LED lamp care about the mains (modified square wave worst case) waveform?

If I was running the UPS and considering we don't have any incandescent or other heavy loads on either of our lighting circuits, could I supply both up and down from the same UPS (I know I *can*, should I)?

If separate, would a suitable sized fuse in each of the lighting feeds (plug tops if left bypassable) be a suitable replacement for the CU MCB.

I'm assuming it wouldn't matter that the lighting circuits wouldn't be RCD protected because they aren't atm.

Should the UPS (ideally) be connected to the std RCD protected side of the CU?

etc etc.

Cheers, T i m

p.s. I'm thinking that if power cuts become a norm in the winter (as they are for some countries / areas now anyway) I can see this sort of thing being a fairly standard option for most people. After all, who wouldn't prefer all their lights to just stay on (for a while till they get ready at least) over stumbling about in the dark looking for torches or the key for the shed and the generator. ;-)

[ARW]

I would say the UPS would not need RCD protection in this case.

[T i m]

Thanks Adam.

So, in addition, would the idea of having both lighting rings isolatable via the use of two 13A plugs (so that I could put the UPS(s) in or not) break any of the more important rules would you say please? FWIW, I could hard-wire the earth across the link so that remains 'real' with or without the UPS?

Cheers, T i m

[ARW]

It is a litle bit odd feeding fixed wiring via a plug but I cannot see anything that bothers me.

I would.

Had a trial run of my parent's invertor today whilst round at their house for dinner. More just to remind my Dad how to use it in anger should he ever need to do so.

[T i m]

Agreed, slightly OOTB but as long as there is nothing fundamentally 'wrong' as such.

.

Check.

Cool. What does that feel OOI?

Cheers, T i m

[Mr Macaw]

I've already done this. I didn't use the lighting fuse in the fusebox at all. I have a 1500VA UPS that powers my computer/printers/monitors/stereo, which is plugged into a normal 13A socket in the ring main, and coming out of that are a few 6 way 13A strips for the computer etc. Into one of those sockets is a plug with a 5A fuse, and the cable runs into the fusebox and connects to the circuit that already fed the lights. Whatever it produces when on battery doesn't piss off any of the incandescent, halogen, CFL, or LED bulbs at all. And in fact since installing it, bulbs last longer because it steps down the voltage when the mains is too high (I've seen it as high as 256 volts). Probably filters other shit out too. It's an old American Power Conversion Smart UPS 1500 I got 2nd hand on Ebay, and fitted with new batteries. One odd thing it does is when on batteries, it outputs -110 and +110 volts on the live and neutral, but unless you're referencing it to earth, the bulbs aren't going to know that. I guess it's because it's American and that's how their electricity is.

[Mr Macaw]

Indeed. All my lights in the entire house stay on with a powercut, aswell as the computer, stereo, internet connection, etc. If need be, most UPS's are happy to run forever (mine has a cooling fan), you can add additional batteries to them as required, just use car batteries.

[Mr Macaw]

Surely the UPS feeds the earth through anyway?

[Roger Mills]

That's fine for lighting but may cause problems if you try to power the electrics of a central heating boiler with it. Some flame detection devices definitely require neutral to be referenced to earth. My Honda genny has a floating output, and I have to strap N to E to power the boiler.

[T i m]

So you have already got what I was suggesting in your house? Does it cover the entire house or just the lights and sorts of devices you listed (I know it couldn't support say a washing machine unless a very big UPS). ;-)

I did actually remove a huge UPS solution with a good few very heavy

12V batteries. Each UPS unit ran from 48V and the battery's were all external (in a frame, like in a telephone exchange). I think I still have one or two of the actual UPS units and they are good *because* the battery supply *is* external (so you can easily do as you say and use whatever batteries you have available (within reason of course).

I know many places (like hospitals) have a 'protected' supply ring that should only be used for power critical equipment (not the kettle or cleaner). ;-)

I think my (24V) APC Smart UPS 1500 has a cooling fan so two nice 'leisure' batteries connected externally could make an ideal solution for my UPS lighting project. ;-)

Cheers, T i m

[T i m]

Whilst it should, I was working on the basis that if I had one of the lighting circuits unplugged it may not be?

Cheers, T i m

[T i m]

Interesting.

Ok.

Ok.

Yup, that was what I was hoping to do but with the UPS under the stairs etc.

Cool.

Yup, they can 'bang and buck I understand (online UPS's that is).

Same here, and I have the 1Kva and several of the 650 CS models.

I believe the 1000 and 1500 units can both take the same battery (just by removing some retaining plates from the battery bay on the 1000). I was waiting till I actually installed the system before buying the batteries, or, use some external ones.

Quite, and as I only intend powering the lights from my solution (I might also have the other unit on the computer gear but with several laptops and a mobile hotspot on my phone, I shouldn't need to).

Possibly. Thanks for the positive feedback.

So, assuming you use low energy lighting and the other equipment doesn't draw that much, how long do you get reserve lighting would you say?

Cheers, T i m

p.s. I can see why people wouldn't like this sort of thing installed for their elderly parents? Much safer than having them plunged into darkness and then faffing about with torches and candles etc?

[T i m]

I wondered about that (not that we have any other appliances that would be powered. Gas fires, gas cooker (battery ignition) and a 'Multipoint' water heater with pilot. ;-)

Understood. Would you know if all genny's (I have a 650W 2/ and a 3KW Honda 4/) would be like this and the same question with the likes of the APC UPS's?

Cheers, T i m

[Mr Macaw]

Just this desk and all the lights. This desk comprises an i3570K with Radeon R9 200 computer, 2 monitors, a stereo, 2 printers, and 2 internet routers (for some reason there's a "fibre router" from BT Openreach aswell as the one my ISP gave me). The UPS has a power level indicator in the front, which does sometimes get all the way up (960W or 1500VA) because I've got some incandescent bulbs left, but as they and the CFLs wear out I'm replacing stuff with LEDs.

This uses 4 batteries (I think it's 4 x 6V sealed lead acid in series, I can't remember).

This one states in the instructions that you can buy a battery unit which looks rather like it does but just holds loads of batteries, which you can link onto it. I think it said you can connect several of them for as long a run time as you want. Of course all that would really be required would be some big car batteries (presumably in pairs in series) wired into it.

Yes, presumably running off something like a UPS, or maybe something even better that generates it's own power all the time to make it perfectly smooth?

It does. That's the one I'm using right now.

I can't remember a powercut longer than a few minutes so I've never got round to adding the leisure batteries. I got it for the computer so a brownout didn't corrupt the disk like it has done before, and doesn't interrupt what I'm doing or lose unsaved work. I added the lights primarily to stop the LED bulbs failing very quickly as my mains varies from 242V to 256V. They don't like that at all. Mind you the latest LEDs I've got say they accept 90V to 260V so they would have been fine anyway.

[Mr Macaw]

What do you mean by unplugged? A mains plug that feeds the lights? Surely then you'd have no live or neutral either?

[Mr Macaw]

-110 and +110 is actually safer and only a problem if some earths and neutrals have been connected or swapped somewhere. I did used to have a PIR powered off live and earth as there was no neutral where I put it (in place of a lightswitch), so that might not have worked on battery as it would only get half the voltage.

Not all low energy lighting yet. I'm perhaps stupidly wanting to wear out the old incandescents and CFLs. Mind you if I'd have changed everything to LED at once, I'd have the shitty LEDs, as they've improved gradually, and they would have cost a lot more to buy.

I take it you meant "can't" or "would".

Indeed. Although depending where you live there aren't powercuts like there used to be. 30 years ago where I used to live as a kid, we could have powercuts for several hours. I'd often produce an old car battery and a car headlamp as I've always liked fiddling with stuff and got stuff from the local scrapyard and skip.