Calling Electrical fundis / UPS fundis

[mancombseepgood]

I have a 1kVA UPS that doesn't get used after hours (when load shedding often occurs in our area). I want to use that UPS to feed one of the plug circuits in the house... or possibly a light circuit. Apart from the obvious overloading precautions, I wondered if anyone had any advice for connecting it up... I have drawn a basic diagram here of the current setup

This is the before setup - i.e. normal operation: http://mybroadband.co.za/photos/showphoto.php?photo=3408&cat=500

... and is the proposed `after' setup - what I am proposing for load shedding.
http://mybroadband.co.za/photos/showphoto.php?photo=3409&cat=500

I imagine that will be safe considering the mains and all other circuits will be off. In addition, I will have to power off all unused outlets so I draw as little as possible... maybe the entertainment system, or maybe a light or two... that's it...

Currently the UPS runs for up to 4 hours with the server and internet stuff attached during office hours, so we can work during load shedding...

Now, are there any creative ways to automate the switch over... or at least guarantee no problems should I forget to down the mains switch and the commercial power comes back on?
I'm no leccie, so I don't know if parallell circuits are supported in AC... or what the implications are of having two live sources connected (boom? )
Any ideas appreciated.

 

[qdada]

It has been looong since my trade test so take what i say with a whole lot of salt and pepper(mint)


Consider getting a 'relay switch' ,well, thats what it was called when i was an 'aapi'.

While this may be the cheapest option it is not the smoothest as there will be a momentary dip between the switch over and that may not be the best option if you are running pc's.

I imagine the best option is getting a ups that is permanently installed on your premises. The idea is that your chosen circuits always draw the power from the ups by default to make the transition as smooth as possible.

 

[mancombseepgood]

It has been looong since my trade test so take what i say with a whole lot of salt and pepper(mint)


Consider getting a 'relay switch' ,well, thats what it was called when i was an 'aapi'.

While this may be the cheapest option it is not the smoothest as there will be a momentary dip between the switch over and that may not be the best option if you are running pc's.

I imagine the best option is getting a ups that is permanently installed on your premises. The idea is that your chosen circuits always draw the power from the ups by default to make the transition as smooth as possible.

Yeah, I think you are referring to a true online model, mine is a line interactive... its not the switch over I am concerned with, it's backfeeding the input line with the output of the UPS but with the mains cut so there is no conflict... after disconnecting the input that is... basically I'm trying to avoid doing any extra cabling to get the UPS connected to my DB which is on the other side of the house... the volt drop will be too big for my liking.

 

[Gnome]

You are talking about a type of parallel connection?

IE. The UPS is connected somewhere in the circuit but not where the actual mains connection is made to the DB?

EDIT: Ok I see you actually stated you are using a parallel connection.

Anyway 2 problems with that setup:

1) The UPS will always have load, not just when power is out, this is where the real problem comes in. In actual fact if it's not disconnected when the power is still on, it can cause a LOT of trouble.

2) Once the power dies, you will effectively be power the entire grid, which is obviously impossible and the UPS will blow, you'll need something to cut power to the rest of the circuit (IE. The DB). Then it should work, although you should be sure not to draw more current than the UPS and the supply wire can handle (IE. the wire the UPS is connected to).

I think this is also against electrical code but I'm not certified so can't say.

 

[mancombseepgood]

Have a look at my pics, no, i wont be powering the grid as the main circuit breaker (among others) will be open (off). And it wont be feeding back to the circuit during normal operation, only when i re-route it manually, which i will only do if i happen to need power in my house during shedding (after hours). Normally it will just feed my router, switch and server during office hours, im on notebook with battery.

 

[FlashSA]

Hi. I have not looked at your photo's or diagrams because i am on my phone but have a good idea of what you want to achieve. Basically a ups and a generator are similiar in that they output power. Now if you turn both your mains AND your earth leakage off, and turn off geyser and other heavy draw appliances, then you can use a male to male plug and plug the output side of the ups into any wall plug in the house and it will power your house lights and plugs. You must unplug the ups charging cable before all of this otherwise you will create a loop (the output from the ups will go through the house and then back into the ups from the wall- not good.) Once power is restored to the grid- unplug the ups output from the wall. Plug ups input into wall and turn all mainsboard switches up to restore eskom power. It's the cheapest way to do things and you can stand the ups anywhere near a plug. I have used this with a generator and it works a charm! About to buy a intellipower 1200watt ups to power my townhouse very very soon and i will use the above method.

 

[howardb]

Based on all the above Q & A's, I would like to do the following, for the DB Lights circuit only:

- remove the incoming AC power line from the "Lights" circuit breaker (after the breaker)
- run that wire after the breaker through to the "input" side of an IntelliPower2 UPS
- there are the 3 standard wires, red (live), black (neutral) and a centre core (earth)
- run a wire from the UPS back to the "Lights" circuit (running from the Distribution Board to the house lights circuit) connecting them back up so that the UPS is in-line with the "Lights" circuit

What I want to achieve is to isolate the "Lights" circuit from the DB, and connect to the UPS, so when there is a power outage, the UPS can still power some existing lighting fittings (outside lights in particular). The AC line running to the UPS would do the charging when the power is back on.

Not sure if this makes sense, but I need to be able to have some outside lights on during these blackouts (after an incident that happened recently), and this is the only way I can think of to use the existing light fittings. I am not able to run additional cables all over the place or through the roof.

Ideas? Would it work? Must an electrician do this re-wiring?

 

[bekdik]

Must an electrician do this re-wiring?

I'd say yes. If it's not carried out by a qualified person, I doubt whether your household insurance would apply.

 

[LabAnimal]

From what i can tell from the diagram. If the UPS is connected and feeding power to the points regardless if it can handle it or not, and the power comes back on, it will blow the ups.

I have a similar idea, whereby i would like to bypass the feed going onto the DB board for the lights, feed it into another trip switch, from there into a UPS, then back onto the DB Board so that i atleast can run a light or two. That way the UPS will do all the work when the power goes out.

as for the PC's - Get standalone UPS's for each PC. That way they are independent, and you minimize the risk of overloading the UPS.


** Something else : I want to get an On-line UPS - What kinda power would i need for 1 PC with 3 CRT Monitors + DSL router ?

 

[mancombseepgood]

From what i can tell from the diagram. If the UPS is connected and feeding power to the points regardless if it can handle it or not, and the power comes back on, it will blow the ups.

I have a similar idea, whereby i would like to bypass the feed going onto the DB board for the lights, feed it into another trip switch, from there into a UPS, then back onto the DB Board so that i atleast can run a light or two. That way the UPS will do all the work when the power goes out.

as for the PC's - Get standalone UPS's for each PC. That way they are independent, and you minimize the risk of overloading the UPS.


** Something else : I want to get an On-line UPS - What kinda power would i need for 1 PC with 3 CRT Monitors + DSL router ?

600va should be fine there... not much draw, but depending on how long you want to keep it up, you may need extended battery.

When the power is restored, nothing will blow unless the mains breaker is closed or in the 'on' position as the internal circuits will be isolated...
I think flashsa hit the nail on the head and confirmed what I suspected.

I have no need for PC's on UPS - the UPS is powerful enough to power my server, net and internet... it's a small office with two battery powered notebooks as workstations... the rest is minimal...

 

[mancombseepgood]

Hi. I have not looked at your photo's or diagrams because i am on my phone but have a good idea of what you want to achieve. Basically a ups and a generator are similiar in that they output power. Now if you turn both your mains AND your earth leakage off, and turn off geyser and other heavy draw appliances, then you can use a male to male plug and plug the output side of the ups into any wall plug in the house and it will power your house lights and plugs. You must unplug the ups charging cable before all of this otherwise you will create a loop (the output from the ups will go through the house and then back into the ups from the wall- not good.) Once power is restored to the grid- unplug the ups output from the wall. Plug ups input into wall and turn all mainsboard switches up to restore eskom power. It's the cheapest way to do things and you can stand the ups anywhere near a plug. I have used this with a generator and it works a charm! About to buy a intellipower 1200watt ups to power my townhouse very very soon and i will use the above method.

Thanks, it's what I thought. Definately it looks like there's no quick way i.e. I should do it and not leave it to the missus
That's fine with me tho, it won't be the regular setup - only the exception.

 

[mancombseepgood]

Based on all the above Q & A's, I would like to do the following, for the DB Lights circuit only:

- remove the incoming AC power line from the "Lights" circuit breaker (after the breaker)
- run that wire after the breaker through to the "input" side of an IntelliPower2 UPS
- there are the 3 standard wires, red (live), black (neutral) and a centre core (earth)
- run a wire from the UPS back to the "Lights" circuit (running from the Distribution Board to the house lights circuit) connecting them back up so that the UPS is in-line with the "Lights" circuit

What I want to achieve is to isolate the "Lights" circuit from the DB, and connect to the UPS, so when there is a power outage, the UPS can still power some existing lighting fittings (outside lights in particular). The AC line running to the UPS would do the charging when the power is back on.

Not sure if this makes sense, but I need to be able to have some outside lights on during these blackouts (after an incident that happened recently), and this is the only way I can think of to use the existing light fittings. I am not able to run additional cables all over the place or through the roof.

Ideas? Would it work? Must an electrician do this re-wiring?

I believe it should be passed by a leccie but don't know if you have to have one do the work.. maybe talk to one who you are friendly with... I'd also be interested to know. It's all internal wiring. I've always done my own. Only when you sell do you need to get the certificate and if you did it all wrong, you will prolly need to pay a bit. ALTHOUGH... insurance may have different requirements.

 

[bekdik]

I think the best solution is to install an new circuit with a the emergency lighting lights on it. The ups can then power this new circuit.

Might even be best to keep it on its own db. As the ups is designed to handle shorts and it is not directly connected to the public electricity supply, you might well get away with installing this yourself.

 

[LabAnimal]

600va should be fine there... not much draw, but depending on how long you want to keep it up, you may need extended battery.

600va ? 3 big CRT's, PC, Plus Router ? i need it to run atleast 3 - 4 hours...

 

[Gnome]

600va ? 3 big CRT's, PC, Plus Router ? i need it to run atleast 3 - 4 hours...

600VA is simply the maximum power the circuit can deliver that does not mean it can deliver 600w of power quite the contrary, you can try and power all those things but I doubt the ups will hold up, as for 3-4 hours, not a chance a UPS will manage that (unless you are using a external battery pack).

Usually the VA rating is the maximum current the transformer used in line interactive UPS's can handle, whereas the inverter is usually less than that specifically because it isn't 100% efficient. Typically 1000VA UPS would be around 600-700W so my guess would be around 300-400W for a 600VA unit.

Best be safe and buy a cheap Watt/Hour meter that plugs into the wall (they aren't too expensive), then plug what you want to run in there and from that determine what UPS you need. Otherwise check the appliance itself, most provide a watt usage rating.

Btw. to the people who want to power an entire home from a male to male standard wall socket, a standard plug is rated for 16 amp in South Africa so if you plan on using more than +-3.5kW you'll fry the plug and possible the wiring (usually the wiring would be a bit higher, around 20amps), so don't go thinking you can plug a 7kVA generator in there and all will be well.

 

[mancombseepgood]

600va ? 3 big CRT's, PC, Plus Router ? i need it to run atleast 3 - 4 hours...

My 1kVA holds up my xeon server, 1x 17 in CRT, switch, router for almost 4 hours with extended battery backup... you may be right depending on the monitors... I would say start at 600va, but consider 1-1.4kVA if you plan to add more equipment. You will need extended battery tho to get those times.

 

[FlashSA]

Btw. to the people who want to power an entire home from a male to male standard wall socket, a standard plug is rated for 16 amp in South Africa so if you plan on using more than +-3.5kW you'll fry the plug and possible the wiring (usually the wiring would be a bit higher, around 20amps), so don't go thinking you can plug a 7kVA generator in there and all will be well.

Point taken - but I have successfully run a 6KVA generator at my dad's house through his garden lights plug without any hiccup. I do have a very thick cable as my male to male plug (so thick you can't bend it) and it powered several lights and 8 fridges, 42inch plasma and PVR with no trouble at all...... for 3 hours non-stop!

I do believe that the garden lights have an uprated ampage on the mains board though.....

With regards to UPS into the house system - the easiest and cheapest way is the way I described earlier in this thread - but yes, you need to do it yourself because letting the kids or wife plug things in is VERY risky!

 

[mancombseepgood]

Point taken - but I have successfully run a 6KVA generator at my dad's house through his garden lights plug without any hiccup. I do have a very thick cable as my male to male plug (so thick you can't bend it) and it powered several lights and 8 fridges, 42inch plasma and PVR with no trouble at all...... for 3 hours non-stop!

I do believe that the garden lights have an uprated ampage on the mains board though.....

With regards to UPS into the house system - the easiest and cheapest way is the way I described earlier in this thread - but yes, you need to do it yourself because letting the kids or wife plug things in is VERY risky!

Yeah, always check the db circuit breaker rating to be sure... those solid plugs with pure brass/copper terminals... not the hollow type as is common these days... should do just fine with 30 amps at least IMO. It's then up to the cable you use from plug to plug... don't go less than 16 amps - rather go higher, depending on your needs...

 

[AirWolf]

My 1kVA holds up my xeon server, 1x 17 in CRT, switch, router for almost 4 hours with extended battery backup... you may be right depending on the monitors... I would say start at 600va, but consider 1-1.4kVA if you plan to add more equipment. You will need extended battery tho to get those times.

Which UPS and battery backup are you using?

A stand-alone 1 kva ups only lasts 40minutes.

 

[mancombseepgood]

I'll check the details in a mo and let you know, got it from UPS direct

http://www.upsdirect.co.za/domestic.html
Its the black one on the left... the battery is in the metal box underneath the intelligence bit at the top. Any UPS should be OK with an extra battery or two tho.