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.

 

[malcolmsanford]

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.

By the looks of things the design will not be an in line type as you would have on a PC rack or at a office desk.

He is looking more as an alternative source of supply and I would imagine that regulation 551.1.1(vi) could be used here and if so then he would need to comply with 551.6.1

All mute points as this is not an "average" concept. But I do see your point Sean and Spins

 

[sean_ork]

I bet he'll buy a torch after he prices this project up

 

[Spoon]

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

It sounds like ukspark is doing this cause he thinks its a good project rather than out of necessity.
As Malcolm has stated, he need to figure out how long he wants this to run.

 

[marc8]

like the link #4,
I know the guy is using at he says for power cuts ECT, but on a dual rate elec meter eco 7 or 10, charging up during the cheap rate & then discharging during the expensive time does look good don't know what the losses would be if any. but hell of a project

 

[uksparks]

Thanks for the replies, I have had an even better idea... Ill let you know shortly, just going to eat dinner!

Seriously the new idea beats the old one and is a lot easier!

 

[shanky887614]

like the link #4,
I know the guy is using at he says for power cuts ECT, but on a dual rate elec meter eco 7 or 10, charging up during the cheap rate & then discharging during the expensive time does look good don't know what the losses would be if any. but hell of a project

could use solar panels on your roof to charge the batteries and a charger to top it up the last bit at night

 

[uksparks]

right ok, here goes, well as you hopefully know, I fitted a Hager Invicta 3 board in my house... See photo below for circuits to show what I mean.

What I am going to do is put everything on L1 that I would like to have UPS power, so basically if i put all the light circuits on L1 and maybe the alarm too, then the incomer at the bottom, remove the link to L1, so the Grid only feeds on to L2 and L3, that means there will be nothing on L1 ok.

So, what I then propose is to have an MCB on L2 in the board feed a wall mount UPS supply of say 3000VA and the load side of the UPS connect to L1 in the bottom of the main switch.

So basically all the light circuits are still independent of each other in terms of earth faults etc, but L1 is ok fed via the same supply, but all the circuits will be via the UPS, so in the event of power failure all L1 circuits will remain running.

No need for contactors or relays etc, this is much better and simpler, and if i was to switch off the main switch, everything will be dead. I see this to be the easiest, safest and most compliant option as the circuits will all be running via the UPS as if they were plugged in the back of it essentially.

as for the earth and neutral and earth, this is where I am not 100% sure, I can take the line from the load side of the UPS and connect it to L1, the earth, I suppose just connect it back on to the earth bar, and the neutral, I can't see it doing any harm putting it back on to the neutral bar?

I don't know though, does that sound ok with the neutral?

Reason for doing this is... Ok we hardly every get a power cut, but I want to be the one house in the street that has all its lights inside and out on like a beacon when the rest of the estate is in darkness!

Its not going to cost a great deal of money for a UPS as thats all I need as have everything else.



I would just need to move a couple of circuits around so that only lights were on L1.

 

[davesparks]

I'd want to know a bit more info on the output of the ups before common Bing up the neutral!

 

[uksparks]

thats my problem, I don't know what it would do or how it would be have etc... Ill be honest, I have no idea.

On one hand im thinking, well the neutral is the same neutral I would think....(i think) and its just the line thats cut and fed maybe?

The other hand says I have no idea?

Im guessing here...

 

[davesparks]

thats my problem, I don't know what it would do or how it would be have etc... Ill be honest, I have no idea.

On one hand im thinking, well the neutral is the same neutral I would think....(i think) and its just the line thats cut and fed maybe?

The other hand says I have no idea?

Im guessing here...

Guessing is no good, you need hard facts! Get researching or get a ups and test it.

Worst cases could be a constant circulating current through the ups or significant constant nuisance tripping of the rcbo's