UPS on light circuits

[uksparks]

Hi,

I have not thought this through yet so don't give me stick yet.

I was just thinking of putting emergency lighting around the house as saw some really slick little LED things which are very discrete, anyway, it made me think, well why not just stick a UPS supply next to the consumer unit to feed a or many light circuits??

Like I say, I have not thought this through yet, but was thinking of using something like a 11 pole relay so you can switch live, neutral and earth.

So you would have a relay which is normally open and the mains grid supply would hold it closed, when the grid dropped out, it would switch to the UPS supply.

The grid would go from the consumer unit, via the RCBO, through the relay and out to the lights, the UPS supply, would be powered from one of the light circuits, the load side of the UPS which would be the offline supply for the lights so to speak, this would then go back into the enclosure via a 30mA RCD.then onto the relay to the light circuits.

Now the only thing would be, at present, lets take three light circuits for example, they are all standalone separate circuits with RCBO's, if i connected them to relays, maybe through in an MCB inline with each for good measure, im just thinking, they will all end up common back one on RCD unless i put at RCD or RCBO on each light circuit and didnt feed the UPS from one of the light circuits, but an MCB on its own.

I guess i would link out all the A1 - A2 terminals to pull each contactor on, so they are all piggy backed off each other so they all switch together.

Can anyone see any issues with this? The other thing i was thinking was what about if the grid was still on and the lights tripped say? would it be a problem running the lights off a UPS whilst the rest of the house is on the grid?

I appreciate UPS supplies are more designed for computers and the like, but I also don't see the problem in doing this.

The other thing i was thinking, would you switch the earth as well? or not? Not sure where the earth would come from if i did switch it to the UPS? Presumably its common with the Neutral?

What do you think? I know it sounds crazy.

 

[sean_ork]

Sounds overly complex, why not just have the UPS inline with the supply to the lights ?

Assuming you've not got 200 halogens you'll not need a big UPS

 

[uksparks]

I don't want all my light circuits running via a common item such as the UPS.

i think I'd probably need an automatic transfer switch as it probably wouldn't comply otherwise.

 

[shanky887614]

I don't want all my light circuits running via a common item such as the UPS.

i think I'd probably need an automatic transfer switch as it probably wouldn't comply otherwise.

https://www.youtube.com/watch?v=xcfd2Ncoeis

a couple people have vids on ones that they have made after seeing what he did

 

[Deleted member 26818]

Would need to disconnect from the grid, otherwise your UPS will be trying to power the grid.

 

[PEG]

No reason why such a set-up could not be designed and made compliant.

Supposing this was not entirely under your control,provision would have to be made,to have drawings available to enable testing to be done correctly.

Also,additions to those lighting circuits,both current and future,such as fan,TV amps etc,would need to be factored in.

....and i think you need to have a Horlicks,after yer tea...instead of coffee and speed...:vanish:

 

[uksparks]

Ive been thinking whilst in bed....

How about, to make things easier, just feed the the UPS supply(s) with an MCB no RCD on them, then from the UPS that feeds an RCBO for each circuit as it is now.

So the lights run via the UPS and you get earth fault protection too, plus no down time on lights in the event of power loss.

So if i move my RCBO's into a different enclosure, replace them with MCB's in the DB, re label them one for each UPS accordingly, and then each ups load side goes to an RCBO in the new enclosure which the light circuit connects to. Then I could integrate some other clever trickery to alert me when I have lost mains power.

Now, the only question is, would I need an earth ROD connected to the MET for this do you think?

I have 6 light circuits, each one has the following load.

Circuit 4: 60W MAX when all on
Circuit 7: 150W MAX when all on
Circuit 15: 60W MAX when all on
Circuit 16: 36W MAX when all on
Circuit 18: 80W MAX when all on
Circuit 19: 105W MAX when all on

I could bunch these into three groups.

 

[malcolmsanford]

As Spin said you need some sort of ATS switch so that your alternative supply would be independent of the main network

your looking at roughly 500watts of power.

How long do you want this to run, that will determine how many batteries you require. Remember a UPS in most situations are simply to allow end users the time to shut things down, or to allow a generator to take over and supply EM power, until mains is restored.

Most EM lighting will last 3 hours on battery back up, are you looking for a longer duration? Then 500watt for longer than 3 hours is quite a hefty battery pack.

 

[sean_ork]

Would need to disconnect from the grid, otherwise your UPS will be trying to power the grid.

Are you sure about that ?

 

[sean_ork]

and then each ups load side goes to an RCBO in the new enclosure which the light circuit connects to. Then I could integrate some other clever trickery to alert me when I have lost mains power.

Are you really pondering a separate UPS for each circuit ?

There's no need for any grid disconnection, the UPS is line interactive, its inline to the supply - there is no chance of it feeding anything other than what it's output is connected to - you won't be back feeding to the national grid.

How often do you get power cuts ? - it must be once a day if you are seriously considering this project.