Copier trips UPS

I think you are headed in the right direction. I would put a DVM in same receptacle that the UPS is in and observe what happens to the voltage level when the printer or copier is turned on. This not a perfect way of determining a lowering voltage level, but it should give an indication if it is dropping. If it is, I would look at all of the connections for that circuit all the way back to the breaker. Any high resistance connection would lower the voltage as more current is drawn.

I probably should add that I tried the equipment on a 20 amp circuit; it did trip the UPS. So I guess that means it is not a problem with the power coming into the house. (The room with the 20 amp circuit cannot be the office, unfortunately.)

I am not sure I fully understand the above statement. If you tried the computer and ALL the other equipment on another circuit and still had the same problem, it still could be you are lowering the input voltage too much for the UPS. Taking the measurements would answer that question.

After all, it still could be a low voltage problem. It could be one that effects ALL circuits. Such as input to the fuse panel.

Copiers and laser printers, when turned on, draw high current - about 5 amps typically - (to heat the fuser) for a short period of time. This causes a voltage drop in the wiring. There *will* be a voltage drop, even if your wiring is 100% perfect. That is normal. When plugged into the same circuit, your UPS will "see" the voltage drop. The UPS will click on, depending on how much the voltage drops and for how long, and on the UPS circuit.

Your situation may not indicate a problem. Typically, it is advisable to run laser printers/copiers on a separate circuit to avoid the annoyance that the periodic voltage drop may create. For example, a light fixture plugged in to the same circuit may dim periodically as the laser or copier re-heats the fuser. So much for normal.

If the voltage at the receptacle drops by more than 3%, then the wiring and the total load on the circuit should be checked. The drop is computed based on the voltage measured at the service panel minus the voltage measured at the receptacle.

Ed

Check the back of your UPS. It may have switches to make it less sensitive to voltage fluctuations. Computer supplies aren't affected buy even moderate fluctuations so should not be an issue. We one lost a phase, computers were running 75 volts. I asked everyone to shut the computer off because that is hard on the supply to operate under that condition for an extended amount oif time. John

I have an interesting update. Haven't tested the voltage yet, but it makes a difference which outlets I use even though they are on the same circuit.

In my testing so far, if the UPS and computer are at an outlet farther than the copier is from the main switch box, the UPS trips when the copier is turned on. If the copier is farther away than the UPS and computer, the UPS does not trip.

My solution may be to move the copier to the end of the circuit. I hope the voltage drop does not cause any damage to the copier. What is a safe voltage drop for electronic equipment like a copier or laser printer?

Vince

Copiers and laser printers can draw a fair amount of current when their heaters kick in.

But even at that, the voltage dip shouldn't really be all that bad.

You *might* have a loose/bad connection in that particular circuit (you mention in another reply that the problem doesn't occur on another circuit). This sort of thing could get worse over time and be a 'bad thing'.

If it's a 15 amp breaker in a fairly new house, I'll take a *guess* that it's wired with 14 AWG wire. About how far away from the service panel is the circuit? Other end of the house? Even at 80 feet, an 8 amp load should only drop about 4 volts.

If you're handy with a VM, measure the voltage at the copier outlet with the copier turned off, then turn it on and measure again. If the voltage drops four volts or more, I'd say you have a problem that needs investigating.

Again, if you're handy with some home DIY projects and such, you can try this. Find *all* the outlets on that circuit. *TURN OFF* the circuit breaker. Go to each outlet, one at a time and do the following: 1) Check with your VM that it really is turned off (safety first) 2) Remove the cover and outlet from the box and check the wiring on the back. 3) If any are 'stabbed' into a hole in the back, then insert a flat-blade screwdriver in the slot next to the hole and release the wires. Take careful note which wires were on which sides of the outlet. Connect the wires to the screw terminals on the same side (wrap around the screw clockwise and get at least

3/4 of the way around) 4) make sure all screw connections are tight.

If you're not comfortable doing this sort of thing, hire a professional to do it for you.

One friend was having problems with his stereo and TV equipment in the living room. We checked all the outlets, and the connections in the service panel. He was getting a large variation in voltage depending on how many things he turned on (TV, VCR, stereo amp, turntable [oops, I'm dating myself]). We *finally* tracked it down to an outlet in the baby's bedroom that just happend to be on the same circuit. Behind the bureau, there was an unused outlet with child-safety caps. When we went to check the voltage there, we couldn't get the caps off because the plastic stabs had been melted from the overheating. The wires on the back of the outlet were loose causing a voltage drop and heating. My friend realised he could have had a fire and was glad to find the problem. We replaced the outlet in the bedroom and the appliances in the living room worked fine after that. Moral is: Be sure to check *all* the outlets on a circuit.

daestrom

This is a case where an analog device might be better.

It's only about 30 feet from the panel.

I guess I could measure the drop at any outlet in that circuit, correct?

In step 3, why do I connect the wires to the same side, and what should I look for after doing these four steps?

Thanks,

Vince

Connect the wires to the same side that they came from!! Sorry, guess that wasn't clear. Most outlets have three different colored screws. Some copper/brass colored on one side, some silver/tin colored on the other, and a green-painted one at the top or bottom. You don't need to remove the wire from the green-painted one (but you can check it tight while you're there). The black insulated wires should be on the copper/brass side, and the white insulated wires on the silver/tin colored side. Best though is to note where they are before you start and just be sure to put them back on the same side. Or better yet, only do one at a time so they don't get mixed up.

If they are *not* 'stabbed' into the back, but are already under the screw terminals, then don't remove them at all, just check each one is screwed down tight. You don't need to break the outlet trying to put 250 ft-lb of torque on the things, if you find a loose one, you'll know. Also check to see that the wire is well under the screws and not just 'caught' by an edge.

Don't connect all the wires to one side of the outlet! I can see how what I wrote could be misunderstood.

Well, *if* you were getting some significant voltage drops when the copier started, and *if* the problem was a loose wire in any of the outlet wiring,

*then* when correcting/tightening the wires, you should not have a voltage drop anymore when the copier starts.

daestrom P.S. One other place that could have a loose connection is where the circuit is attached inside the main service panel. But going in there should be left to someone with more experience in such work. It can be dangerous. P.P.S. As I said before, if you're not comfortable doing this, hire a professional. But as most DIY folks can change out an outlet or wall switch, you can probably do this. (REMEMBER TO TURN OFF THE BREAKER AND CHECK EACH OUTLET DEAD WITH A VOLTMETER AS YOU GO)

Although a digital meter with max/min recording is handy for these types of problems.

Ben Miller