Adding UPS to light circuit

[philoÂÂ]

Nice way to take down a tower.

[DerbyDad03]

Yep. The T building that they "missed" is where I spent countless hours during my year there. There was a 1/4 mile enclosed walkway from the station to the T building. Call it an above ground tunnel. We had a couple of old bicycles with big baskets as wide as the handlebars for carrying parts to and from. There were a few lights along the wall so it wasn't pitch black in the tunnel. Dark, but not pitch black.

One day lightening struck the tower and started a fire in the antenna coupler inside the building. It also killed power to the building which took out the lights in the tunnel. There was an small emergency light at each end of the tunnel but for the most part the rest of the tunnel was now pitch black.

When the alarm went off, being young, foolish and dedicated, I jumped on one of the bicycles and headed for the T building down the long dark tunnel. Those were my babies and I had to save them. Since I couldn't see anything except for the faint light at the end of the tunnel, I leaned the big basket against the ice covered wall and pedaled as fast as I could. I had walked the tunnel so many times that I knew there was nothing to hit so I just kept peddling as the light faded from behind me and kept going until the light at the other end allowed me to see again.

I made it to building, grabbed a fire extinguisher from the front room, felt the door to the transmitter room for heat, opened it slowly, went in and emptied the CO2 into the antenna coupler. My heart sank as I saw the burnt mass of copper tubing and ceramic resistors. Antenna couplers _never_ go bad, so no one keeps a spare on site. I knew we would be off air for at least a week. If a station is off air for more than one minute per month, you have ruined a "perfect month". We had just gotten an award for 6 straight months of zero off air time. The run was now over...big time.

[clare]

IF he wires it correctly he can use bell wire. But what he can NOT do is wire 100 watts of LED on a single run of bell wire because that requires almost 10 amps of current - on a wire that is only rated for

2.3 amps for power transmission.

[trader4]

I didn't say he couldn't do it. I just said that NEC applies to low voltage circuits run within a house too, and that I have doubts that using telephone wire to power lights will meet code. Whether it's DIY or done by an electrician code still applies. If he wants to ignore that, he's free to do so.

[The Daring Dufas]

Forgive me for not remembering that others will not take into consideration those things I do without thinking. Those little panels with 48 SMD LED's draw very little current and like any other electrical project I've ever done, I will figure in the current draw of the project before I install anything. I haven't measured the current draw of the little SMD LED light panels but I'm sure it's not much at all.

TDD

[clare]

One that I installed in my brother's RV was 3 watts. That's getting awfully close to the limit on the bell wire. ANd PHONE wire is generally 22 guage, not 18 - so NO. You cannot use bell wire to wire a house for low voltage lighting...

[The Daring Dufas]

Nope - no approved ways I know of. Lots of jury-rigged possibilities

It strikes me as kind of odd to use a UPS unit to convert 12-24vdc into

120vac to power low current LED lights when the power loss converting DC to AC with the UPS unit is so wasteful. I would consider a 12vdc lighting. All the new emergency exit lights I see are LED units so the OP could get LED table lamps that plug into wall outlets which would come on automatically when the power went out. Very simple plug and play which would be a lot less complicated than any rewiring. ^_^

TDD

[clare]

Under NORMAL USE a standby UPS is NOT converting DC to AC and turning it back into AC. That only happens with "dual conversion" or "online" UPS units. A standby UPS is, in effect, an automatic transfer switch, a battery charger, and an inverter. When there is power on the line in, it transfers (connects) directly to the line out. When the line in fails, the automatic transfer device shuts off the connection between line in and line out, pawers up the inverter, and connects the inverter output to the line out..

When line power resumes, the unit transfers from inverter output to line power, shuts off the inverter, and recharges the battery. This is how better than 90% of "consumer grade" UPS units work - and all "standby lighting" ups units. Dual Conversion UPS units are more expensive, less common, and less efficient - but classify as a seperately derived power source and TOTALLY decouple from line noise, harmonics, etc that can upset some very sensitive equipment.

And any UPS of ANY size runs on 36 volts or more - most on 48 and 60 volts.

[The Daring Dufas]

Nope - no approved ways I know of. Lots of jury-rigged possibilities

I rescue and repair UPS units. I have a 1kw unit on the floor behind me and a 750w unit on the counter to my left. Both units have two 12v AGM batteries in series internally and an external connector for extra 24v battery packs. I have dealt with UPS systems that were the size of a bedroom closet and filled with a dozen batteries of the size one would find under the hood of an automobile. The UPS units I possess put out a modified square wave which computers and such equipment find acceptable. I've only had to install true sine wave UPS units to power certain phone systems. ^_^

TDD

[The Daring Dufas]

Then use landscape lighting wire or 18-16AMW stranded low voltage alarm or sound system cable. An alternative is what I do when installing CCTV cameras. I install a central 12vdc power supply and separate low voltage cables to each camera. A multi terminal central power supply used for CCTV cameras would be a good choice. It's not rocket surgery. GEEZ!

TDD

[trader4]

Again, he can do whatever he pleases, but landscape lighting wire is most likely not rated for use inside a building. What you proposed he wire up is a Class 1 low voltage circuit and it's covered under NEC.

An alternative is what I do when installing CCTV

It's not rocket surgery, but that doesn't mean that there aren't codes that are supposed to be followed. Why do it half-assed instead of reading the code, using the right materials, and doing it right? As an example to the practical problems you're left with, if someday he goes to sell the house, an inspector seeing phone wire used for low voltage lighting may flag it. Then he has a problem that he could have easily avoided by doing it right.

[Robert Green]

Here's a scenario where the impossible becomes lethal. The power goes out. Someone reading this decides to create a male to male power cord. He plugs one end into his UPS's powered outlet and the other end into the outlet nearest his table lamp. The table lamp lights up! Just what the OP wants. Other LED lamps in the house will also probably light up until the fridge or the furnace kicks on or the utility power comes back on. Not sure what happens then.

I agree with your observation, generally - no one is likely to connect the UPS to the grid in a way that will cause energization of the grid outside the home. But never underestimate the ingenuity of someone trying to accomplish a goal. It's very simple to do with two extension cords,.a wire cutter and some wire nuts. In normal UPS operation, I agree, backfeeding is not very likely, but it's not impossible.

The method I described would actually work pretty well if all circuits but the ones powering the LED lamps were turned off at the breaker panel along with the main breaker. But if that main breaker is ON then 110VAC is likely traveling outside the home.

[The Daring Dufas]

I've installed both power and low voltage wiring in homes and businesses and never failed an inspection. Of course, because I was doing it professionally, most if not all of my wiring was concealed. All the wire met code for the circuits carrying low voltage even if it was two pair phone wire. I wired a lot of systems with beige or gray two pair phone wire and never had a problem with an inspection. The only consideration is the amount of current the wires will carry. All of the manufactured low voltage devices I've installed had a label with the amount of current each device used. If I installed home made DIY low voltage LED lights, I'm going to measure the current draw and run low voltage wiring that will carry the load, even phone wire. You keep making it way too complicated. o_O

TDD

[clare]

You misunderstood me. By "of any size" I meant any large UPS - not "all UPSs.. The little cheap crap runs on 12 volts. The intermediates run on 24. 1000 watts and up GENERALLY run on higher voltage. My Powerware Presige 1000 units rin on 48 and 60 volts. So do their

750 watt units.

And as far as "modified square wave" and "quasi sine wave" it's semantics. How many steps for quasi sine, and how few for modified square? True sine is different (much more costly) technology - which, as you note, is generally not required - certainly not for a lighting unit. It's one of those "cabinet style" units the OP needs to install for lighting because they have no plugs. But he does not need the dual conversion that MOST of those cabinet units run.

[trader4]

From my reading of the code, the system you recommended is a Class 1 low voltage circuit. I believe you proposed using a 12V battery kept charged with a battery charger to power the LED lights which would be installed in the house. Clearly phone wire is not code compliant for that application. May an inspector pass it anyway? Maybe in some places and maybe not in others. The enforcement level probably isn't going to be the same in a townhouse in NYC as it is in a small town in the Midwest All I'm saying is that there are NEC codes for this type of thing and in my reading of them, you can't use phone wire. It's not even clear what phone wire means anymore, as it's usually referred to today as Cat5. My reading of the code says the minimum allowed is

18 gauge.

I wired a lot of systems with beige or gray two pair phone

It's not just a matter of the current the wires will carry. Read Article 725 of NEC on what specific cable types are allowed. It's like saying you can use any wire for 120V circuits, all that matters is the current carrying capability.

All of the manufactured

It's not complicated to follow code and do it right. Is it that complicated to use the proper 18 gauge wire? In my reading of the code, that's the minimum wire size allowed for what you proposed. Have you read Articles 720, 725?

[clare]

The UPS would shut down almost immediately, as the grid load would present WAY to much of a load (unless it was a HUGE UPS - but yes, it is impossible to limit stupidity.

Also, if the UPS is plugged into the grid, as soon as the grid comes up from geing connected to the ups, the ups would shut down - shutting down the grid , turning the UPS back on, making the light flicker. So EXTREMELY u nlikely - even in the "idiot" scenario you managed to come up with ........

[clare]

Not everyone has the sense you have. And that's what's scary!!

[trader4]

You might want to read NEC Articles 720, 725 that specifically cover low voltage circuits, instead of being wrong on the code yet again.

[The Daring Dufas]

My house lighting is all LED total wattage with all on is less

Nope - no approved ways I know of. Lots of jury-rigged possibilities

What gets me about the whole topic of using a UPS to power low wattage LED lamps strikes me as bizarre. It would be so much simpler to get LED lamps with built in batteries that would come on or continue to stay lit when the power goes out. If I wanted uninterpretable lighting, I can come up with several less complicated ways to do it. Heck, for many years, I installed fluorescent fixtures that had built in battery backup systems. Plug and play would be less complicated and so much easier. I found a new one that's screw and play and I'm sure there are others. ^_^

TDD

[The Daring Dufas]

I've installed thousands of feet of single and multi pair stranded 18 gauge jacketed wiring for all sorts of things. If the equipment I'm installing calls for it, I will use it. Some cities have their own version of the NEC. An example is Birmingham where I live which has a stricter interpretation of the NEC than the county I'm in. I remember reading something about New York where surge arrester multi outlet receptacle strips are not allowed. I imagine which planet your on would make a difference in the type of wiring that's required. ^_^

TDD