Installing a UPS at a breaker box?

It would help if you included your country/state details. Regulations vary and this is an international group.

Also the wattage of the projector would help.

One option may be to remove the batteries from a UPS* and replace them with much smaller ones that will weigh far, far, less. A UPS is generally designed to run for much longer than a minute and has batteries to support that run time - which you don't need. Most of the weight of a UPS is the batteries it contains.

*Or buy a UPS off ebay without batteries.

Another is to identify the source of the short interruptions in supply and fix that..

Well I think you should have enough battery backup for 10 minutes so that if the power goes off you can turn off the projector and it can cool off the bulb extending battery life....

| I have a TV projector that is mounted on the ceiling and plugs into a | nearby outlet, also on the ceiling. Although it's nice that I don't | need to run a power cord along the ceiling to a wall outlet, there is | one drawback: I can't plug in a UPS (uninterruptible power supply). I | have not been able to find a UPS that is small and light enough to | hang from a ceiling outlet. I only need enough power to run the | projector for less than a minute, since I'm concerned about the split- | second power outages. | | Therefore, I was wondering what it would take to connect a UPS at the | breaker box. I would need to hire an electrician to do the actual | work, but I know that if I call up some random electrician from the | phone book and try to explain what I want, I won't get anywhere. | | So could someone tell me what I need to know and do to get what I want?

One option:

Outlet for projector is wired in the normal in-wall way (you cannot use cord type wiring inside the walls) but leads to a small breaker box with just one breaker rated for the wiring involved. That breaker box is fed from an "inlet". That's basically a "plug" in a box which is connected with an "outlet on a cord". The breaker box is a must so it is a protected circuit. What is basically an extension cord has the outlet side connect to the plug box inlet, and this plugs into the UPS to get power. The UPS then plugs into another outlet which is a normal circuit. The breaker box and inlet for it can be in another room, perhaps next to the main panel if that is convenient enough for you to put the UPS there.

I cannot say if this would be acceptable to the inspector in your jurisdiction. It probably would have to be inspected as new wiring.

It sure as hell would be better than a ceiling mounted UPS! :-)

Ed

Austin, Texas, USA.

I haven't measured it myself, but the spec says 260 watts.

The UPS would still hang from the ceiling. I don't have any kind of bracket or shelf that I can use for the UPS, and my wife does not want me to add any more "stuff" there.

I have a this surge protector already:

As you can imagine, I plug it directly into the ceiling outlet, and it just hangs from the ceiling without any additional support. I was hoping I could find a similar size/weight UPS to use instead. I'm surprised no one has made a small UPS that can handle one-second power outages, because those are the most common in my area.

It's external to the house so I don't think I can control it. When it happens, *all* power goes out for a split-second.

True, but those kind of blackouts are rare. I'm willing to sacrifice size and weight to get just the protection I'm looking for.

Besides, the real problem is plugging in the UPS itself. If I had an outlet near a shelf or floor, I could use any old UPS.

Yes but if the unit is turned off with out proper cooling it can blow a bulb..... and that can cost you $350.00

I don't see any problem with doing what you want to do.

I especially don't see any problem "explaining" to an electrician what you want to do.

It's not all that different than wiring one circuit through an isolation transformer or from an outside generator.

You want to be sure that the ground path remains in place even when the UPS is taken out of service.

You might suggest that the cable to the projector "terminate" at a FEMALE "twistlock" connector. There would be a redundant ground path independent of the "twistlock."

Frankly, the best place for the female connector would be near where the computer or other A/V "stuff" is located rather than the CB panel. The same USP could be used for the projector and whatever else you want to stay up during the outage.

Please explain how not cooling a lamp quickly causes it to "blow".

IIUC, the heat from the cooling components (including the lamp) is trapped in the unit and can only escape by transfer to adjacent components. Eventually this trapped heat will reach and raise the temperature of the case and be lost to the environment.

However, in the process, many components within the case will have their temperature raised to greater than their design temperatures. The one thing that is still likely to be unaffected is.. the lamp..

| Please explain how not cooling a lamp quickly causes it to "blow". | | IIUC, the heat from the cooling components (including the lamp) is | trapped in the unit and can only escape by transfer to adjacent | components. Eventually this trapped heat will reach and raise the | temperature of the case and be lost to the environment. | | However, in the process, many components within the case will have their | temperature raised to greater than their design temperatures. The one | thing that is still likely to be unaffected is.. the lamp..

When the fan is operating, the cooling process taking place is different than the cooling that would take place simply by thermal transfer between adjacent components. The fan would be increasing the rate of such cooling. But in addition to that, the fan is changing what parts are being cooled at what rate.

I'm sure you will agree that the bulbs get very hot. But that temperature is not uniform over all parts of the bulb. The interior of the glass is hotter than the exterior. And the base is likely cooler than the business end of the bulb. With airflow from the fan, a steady-state condition can be reached which has specific temperatures at specific parts. Shut off the fan _and_ the filament, and the bulb now has a heat flow different than during operation. In this situation, the exterior of the bulb will now have a rising temperature as the interior cools down. This is because at the steady-state condition that was interrupted, the interior was much hotter than the exterior.

The fan is preventing the exterior glass from rising to the temperature of the interior glass. It also prevents components that may be near the bulb from rising to such high temperatures. The heat inside the bulb does not just vanish when the bulb is shut off.

I've always wondered about that myself, but every projector I've seen has the same behavior. The manual warns against removing power until the fan has cooled down. In addition, you can power the projector back ON until the lamp has finished cooling down.

And by "cooling down", I mean until the fan has finished running and some time has passed. I have no idea how much cooler the fan actually gets during this process.

My guess is that the reason this is necessary is that the projector cannot handle large differences in internal temperatures. When the projector turns off, the bulb is still very hot but the rest of the projector probably cools down quickly. This might create thermal stresses.

I once broke the glass color wheel of another projector by putting a drop of WD-40 inside the motor. I think the WD-40 causes a temperature difference that shattered the glass.

independent

MALE, MALE, MALE

Sorry about that

| I don't see any problem with doing what you want to do. | | I especially don't see any problem "explaining" to an electrician what you | want to do. | | It's not all that different than wiring one circuit through an isolation | transformer or from an outside generator. | | You want to be sure that the ground path remains in place even when the UPS | is taken out of service.

If the video source the projector displays is connected separately such that disconnecting the ground path to the projector does not disconnect it also to the video source, then maintaining the ground connection is important.

But a big question is how to do that correctly. Normally a ground path needs to follow the power path closely. But if the power path is through the UPS, and the ground must remain present when the UPS is removed for service (and one has not yet connected a bypass cord), an existant ground path would have to be where the power (when connected) is not.

Consider a pair of adjacent ports, one a regular single outlet, and the other an inlet leading to a small breaker box. The ground could be tied between the outlet and inlet. They might even be in the same box. Is that a safe installation?

| You might suggest that the cable to the projector "terminate" at a FEMALE | "twistlock" connector. There would be a redundant ground path independent | of the "twistlock." | | Frankly, the best place for the female connector would be near where the | computer or other A/V "stuff" is located rather than the CB panel. The | same USP could be used for the projector and whatever else you want to stay | up during the outage.

It should be where the UPS is most convenient, when in many cases would be near the A/V stuff. But in some other cases it might not. But in either case, the circuit fed by the inlet needs appropriate overcurrent protection.

On Fri, 25 May 2007 12:21:47 -0300 John Gilmer wrote: | |> You might suggest that the cable to the projector "terminate" at a FEMALE |> "twistlock" connector. There would be a redundant ground path | independent |> of the "twistlock." | | MALE, MALE, MALE | | Sorry about that

Heh, I missed that one in your previous post :-) Easy mistake to do in typing. I hope it isn't so easy a mistake during installing :-)

I think that's what I'm going to do, thanks. It does make a lot more sense, and a UPS would probably overheat if it were located in the garage next to the breaker box.