What's up with my Garage/Shop?

[Mac McQuinn]

I have an unusual situation in my Shop/Garage. At night when triggering the electric garage door opener, the Mercury light mounted on top of the garage will go out and re-light once garage door is open. This happens 9 times out of ten although not 100% of the time. I know the door opener and Mercury light are on the same 20 amp circuit and have been since house was built in 1977. I have a wall receptacle w/ switch at top which will shut off power to both light and garage door off if flipped. The electric garage door opener and door are original to the house. The Mercury light is at least 10-12 years old and other than replacing the bulb (3) years ago there have been no issues. The door opener has seen better days & is probably getting tired. The door's springs & rollers have been replaced 14 months ago and a motor drive gear was replaced 7-8 years ago.

*Tonight I also noticed when using the drill press, the light went off again and soon as I turned the DP off, Light restarted. Any suggestions or ideas on what could be triggering this?

Mac

[Jerome Hanby]

Wonder if the ballast is going "bad". Maybe "noise" on the line when something else is running is throwing it off into left field...

[Van Huskey]

I am also guessing the ballast is getting weak. BUT that is just a guess, I have a bunch of goofy theories but none of them are cogent enough to spell out here.

[Steve Kohn]

I am no electrician but I'd take a look at the grounding for your garage. Do you have a pony box or panel running off the main panel in the house? There are very definite rules on where the neutral and earth grounds can be connected. They way you are describing your problems it sounds like your ground has broken to the circuits in the garage. Others, much better qualified than I, can either correct me or fill in the blanks.
'

[Mac McQuinn]

Steve,
No panel or pony box. Other than the receptacle w/ switch mounted in garage which will turn off power to the door opener and light, everything runs off the house main box. I'm suspicious of the ballast/starter on light, feel it might be getting weak and draw on line might be causing it to shut off power to the light. Waiting for snow to melt off roof so I can investigate further.
Thanks, Mac


I am no electrician but I'd take a look at the grounding for your garage. Do you have a pony box or panel running off the main panel in the house? There are very definite rules on where the neutral and earth grounds can be connected. They way you are describing your problems it sounds like your ground has broken to the circuits in the garage. Others, much better qualified than I, can either correct me or fill in the blanks.
'

[Van Huskey]

I'm suspicious of the ballast/starter on light, feel it might be getting weak and draw on line might be causing it to shut off power to the light. Waiting for snow to melt off roof so I can investigate further.
Thanks, Mac

The other thing that may be complicating things is the temperature. Just a guess but ballasts seem to hate to fire MV and HID lights in the cold, they take longer and flicker more in the process. Weak ballast, cold temps and extra current draws on the line may drop the voltage just a few volts, with a strong ballast a non-issue, maybe with a weak ballast it causes problems. Hopefully, this is the case, not too expensive to fix and beats one of those strange electrical problems that are difficult to track down.

[Steven Green]

I had a similar problem at my old shop. Turned out to be a maple limb just brushing my triplex with leaves in the wind. Made the mecury light go nuts and once in a while the garage door would stop on the way down and go back up. Not a lot of fun in the middle of a thunderstorm.

[Charles Lent]

You have a poor connection of one of the power wires (white or black) in that circuit between the 20 amp circuit breaker in the panel and the garage outlet. When a significant load, such as a motor is connected to it in the garage the resistance of the poor connection causes a voltage drop that is sufficient for the light to go out. You will need to find where this poor connection is and correct it to fix the problem. The first step is to identify all of the outlets, lights, etc. that the breaker operates. Then see if you can determine which are affected when you connect a motor, like a vacuum cleaner, to each of them one at a time. Plug the vacuum into each outlet and have someone watch the light when you turn on the vacuum. The poor connection will likely either be in the receptacle box that the vacuum is plugged into or the previous one toward the circuit breaker. If the light goes out when the vacuum is connected at the outlet nearest the breaker panel you should also check the wire termination on the breaker itself.

You have to be a good detective to find problems like this. I once had a woman complain that almost every time that anyone flushed the toilet in her home, the TV in the living room would turn off. This was traced to a poor connection in a sub panel that fed both the living room, where the TV set was located, and the well pump. The poor connection was in this sub panel.

An old house main fuse that had gone high in resistance was the cause of confusing symptoms in another customer's home when an electric clothes dryer was installed for the first time. When the dryer was running the lights in the living room would be bright, but when the dryer shut off the lights would go dim. It turned out that the fuse was lowering the supply voltage of the main wire that was feeding the living room and other parts of that side of the house and when the dryer was on power was feeding through it from the other main and raising the voltage on the living room circuit. Replacing the house main fuses was all that was necessary to correct the problem.

If you work in the electrical field long enough you will run into all kinds of problems similar to these. I have always considered them a great mental challenge and wouldn't give up until I found the cause.


Charley

[Mac McQuinn]

Charley,
Certainly sounds like you've dealt with this before. The odd thing is the garage door opener does not always kick the light off....as happened last night after coming home from some shopping. This said, The single receptacle with switch at top would be my best guess without running a check for draw at this point. The switch at that receptacle will turn on and off both the garage door opener and Mercury light without effecting any other lights or receptacles in the garage. Plus it's the same receptacle the drill press was plugged into the night running it kicked off the light. Once it gets dark tonight, I'll try to pinpoint things better.
Thanks everyone for all your help,
Mac




You have a poor connection of one of the power wires (white or black) in that circuit between the 20 amp circuit breaker in the panel and the garage outlet. When a significant load, such as a motor is connected to it in the garage the resistance of the poor connection causes a voltage drop that is sufficient for the light to go out. You will need to find where this poor connection is and correct it to fix the problem. The first step is to identify all of the outlets, lights, etc. that the breaker operates. Then see if you can determine which are affected when you connect a motor, like a vacuum cleaner, to each of them one at a time. Plug the vacuum into each outlet and have someone watch the light when you turn on the vacuum. The poor connection will likely either be in the receptacle box that the vacuum is plugged into or the previous one toward the circuit breaker. If the light goes out when the vacuum is connected at the outlet nearest the breaker panel you should also check the wire termination on the breaker itself.

You have to be a good detective to find problems like this. I once had a woman complain that almost every time that anyone flushed the toilet in her home, the TV in the living room would turn off. This was traced to a poor connection in a sub panel that fed both the living room, where the TV set was located, and the well pump. The poor connection was in this sub panel.

An old house main fuse that had gone high in resistance was the cause of confusing symptoms in another customer's home when an electric clothes dryer was installed for the first time. When the dryer was running the lights in the living room would be bright, but when the dryer shut off the lights would go dim. It turned out that the fuse was lowering the supply voltage of the main wire that was feeding the living room and other parts of that side of the house and when the dryer was on power was feeding through it from the other main and raising the voltage on the living room circuit. Replacing the house main fuses was all that was necessary to correct the problem.

If you work in the electrical field long enough you will run into all kinds of problems similar to these. I have always considered them a great mental challenge and wouldn't give up until I found the cause.


Charley

[Dan Case LR]

Check the breaker on that circuit. If it's original (and it probably is) it may be your point of failure. After 30+ years of use (and in the garage/shop, maybe even a little abuse once in a while) breakers can get flaky. I've seen older breakers that would sputter just a little when a heavy load kicked in. If the startup surge from the motor in the opener or drill press causes a similar sputter, you might not notice a super-brief interruption, but your mercury light will go out. Worth checking. If the breaker is at fault, it may also be warm (or HOT!) to the tough. A hot breaker is a breaker waiting to start a fire, so if it's hot, replace it immediately.

D.

[Charles Lent]

Mac,

If you are sure that the problem only exists at that one outlet, the bad connection may be right there. Take it apart and check the connections (with the breaker off). The bad connection should be relatively easy to spot. There will likely be some burning or discoloration of the metal connections, the wire, and the insulation around it. It may even pull apart as you remove the outlet from the box.

There are many grades of electrical hardware, and the price varies accordingly. Houses that are built in developments get the cheapest grade available because the contractor is avoiding every extra expense that he can. I never buy electrical hardware by the price alone. If it's going to be used in MY home or shop I pick a good commercial grade. The cheap grades of outlets will loose their ability to make good contact with the pins of the inserted plugs very quickly and the cheap switches will fail quickly if they have to switch any motor loads. You should never use the "push-in" connectors on the backs of the outlets or switches as they are also a source of problems. Wrap the wires around the screw terminals and tighten the screws well. Tighten the wirenuts as tight as you can using your fingers too. I always follow this up with a few wraps of electrical tape wrapped so that the tape bridges and seals the joint between the wire insulation and the body of the wirenut. This helps to keep the wirenut tight and also keeps anything from entering the connection and shorting out. A poor electrical connection will get hot, causing corrosion, which will make the electrical connection deteriorate, which will make it get hotter and deteriorate faster, until it fails, or starts a fire.

Charley

[Dan Case LR]

Mac,

If you are sure that the problem only exists at that one outlet, the bad connection may be right there. Take it apart and check the connections (with the breaker off). The bad connection should be relatively easy to spot. There will likely be some burning or discoloration of the metal connections, the wire, and the insulation around it. It may even pull apart as you remove the outlet from the box.

There are many grades of electrical hardware, and the price varies accordingly. Houses that are built in developments get the cheapest grade available because the contractor is avoiding every extra expense that he can. I never buy electrical hardware by the price alone. If it's going to be used in MY home or shop I pick a good commercial grade. The cheap grades of outlets will loose their ability to make good contact with the pins of the inserted plugs very quickly and the cheap switches will fail quickly if they have to switch any motor loads. You should never use the "push-in" connectors on the backs of the outlets or switches as they are also a source of problems. Wrap the wires around the screw terminals and tighten the screws well. Tighten the wirenuts as tight as you can using your fingers too. I always follow this up with a few wraps of electrical tape wrapped so that the tape bridges and seals the joint between the wire insulation and the body of the wirenut. This helps to keep the wirenut tight and also keeps anything from entering the connection and shorting out. A poor electrical connection will get hot, causing corrosion, which will make the electrical connection deteriorate, which will make it get hotter and deteriorate faster, until it fails, or starts a fire.

Charley


Excellent points, Charley. My two biggest pet peeves are those lousy "quick wire" outlets/switches and loose wirenuts. Back when I was a kid and my dad taught me how to wire a house, he taught me to always use a pair of lineman's pliers for those last few twists--the long body of the tool in line with the long part of the wirenut, and the pliers "just kissing the wirenut, not trying to spend the night." I'm 57 and I still do it that way, and I've heard guys cuss me because my wirenuts are so hard to remove. That's the way they SHOULD be.

A few years back when we were building the broadcast center where I still work, one of the guys working with me had a special bit for his drill that was designed to apply wing-style wirenuts. Very handy, worked extremely well, but not faster than my lineman's pliers. I think the drill hadn't had enough experience yet. :)

D.

[Mac McQuinn]

I started checking things last night with the use of my shop vac and was able to trigger the mercury light to shut down w/ (3) of (4) different receptacles. Checked all receptacles and reading w/ no load was 121.2 Volts. I pulled the switched receptacle today and while everything seemed good and tight, body of receptacle appeared to have some give to it when checking tightness of screws. What I really did not like was the person who wired this used one of those very small, square edged boxes and since this is the switched receptacle, there is a ton of wires in it, crammed tight . Also noticed he ran a jumper ground wire using coated braided wire! I did not see any evidence of heat or bad connections.

In the next box, about 5' away, I felt I'd found the culprit, one of the white wires was semi loose, requiring a 1/4 turn to tighten plus it appears to have some green corrosion at screw/wire connection. Unfortunately after returning from purchasing some new receptacles tonight, the light was once again triggered by garage door opener, odd since this morning wife said it did not go off when she left for work.

I feel the problem may still be in the Switched receptacle and I do not like the looks of the interior of both boxes I opened so I called a Master Electrician friend, just waiting for a return call. I can make good clean connections although the switched box looks like a mess and I want someone who know the principles to clean things up.

Will post what is found,
Mac

[Mac McQuinn]

Well after trying to trigger the Mercury light to go out at night with the garage door opener for (3) days, it finally kicked the light off tonight and I had a meter plugged in to watch current drop. Voltage only fell 1.2-1.5 V Max. All connections are secure at receptacles in garage and at 20 amp breaker in box. My guess at this point is the ballast at the light although with 2" of frozen snow on the roof and the light being suspended 8' from the peak, it's going to be a while before I can safely drag a ladder up there to check things. At this point I don't really know what else to check. Any ideas?

Thanks,
Mac

[Rod Sheridan]

Low line voltage is causing the arc in the lamp to extinguish.

Once the arc extinguishes the ballast has to restart it.

Check the ballast and capacitors, as others have indicated check wiring devices.

......................Regards, Rod.

[John McClanahan]

I agree with Rod. I would look for a poor or loose connection in the wiring chain. The voltage dip you saw on your meter was probably far greater. It happened too fast for the meter to show. I believe a hot lamp is hard to re-ignite, and needs some cooling time. That's why the light comes back on after the door is opened or closed.

John

[Mac McQuinn]

It seems with approximately 8-10 seconds to raise the door, the meter should be able to indicate a considerable drop in line voltage if there was a weak connection. While activating the garage door opener, I checked current draw at the switched receptacle which turns off power to both garage door opener and Mercury light. I believe a 2 volt drop would be considered normal when turning on a 1/2-3/4 hp. motor to raise a heavy composite 16' wide door.

Mac


I agree with Rod. I would look for a poor or loose connection in the wiring chain. The voltage dip you saw on your meter was probably far greater. It happened too fast for the meter to show. I believe a hot lamp is hard to re-ignite, and needs some cooling time. That's why the light comes back on after the door is opened or closed.

John

[Jim Neeley]

Hey guys... While it may well be the power draw on the opener, it may also be from the vibration caused while the door is opening or closing bringing to life another (?wiring?) issue.

[Rod Sheridan]

It seems with approximately 8-10 seconds to raise the door, the meter should be able to indicate a considerable drop in line voltage if there was a weak connection. While activating the garage door opener, I checked current draw at the switched receptacle which turns off power to both garage door opener and Mercury light. I believe a 2 volt drop would be considered normal when turning on a 1/2-3/4 hp. motor to raise a heavy composite 16' wide door.

Mac

Mac, the issue is the instantaneous voltage dip during motor starting, not during motor running.

The voltage dip during starting could be 20 to 30 volts.............Regards, Rod.

[Mac McQuinn]

To brings things up to date, we had a thaw on Monday of this week so I was able to get on the roof with a fresh bulb to do some basic troubleshooting. I determined the old bulb was tight although removed it to install a new bulb since I was already up there and any new snow would keep me off the roof for a while. I then used a long piece of dowel to place a large red plastic cup over the light sensor to activate the light. After a couple minutes the light came on and as I happen to take my garage door opener remote up on the roof with me, I triggered the door opener several times with no resulting shutting off or even flickering of the light as before.

Since Monday and replacement of the bulb, the light has not been affected by using either the garage door opener or my shop vac at night. Usually a surefire method to trigger the light to shut off is by running my drill press with all my shop lights on although In running my 1/2 hp drill press press tonight, the light was unaffected, not even a flicker.

One thing I noticed, even though the new light bulb is the same specification, it's noticeably brighter than the old one.

Thanks to all for suggestions, etc
Mac

[Mac McQuinn]

Just as a followup; 3 weeks today and no signs whatsoever of light flickering or shutting off.
It appears the bulb was the culprit.

Mac



To brings things up to date, we had a thaw on Monday of this week so I was able to get on the roof with a fresh bulb to do some basic troubleshooting. I determined the old bulb was tight although removed it to install a new bulb since I was already up there and any new snow would keep me off the roof for a while. I then used a long piece of dowel to place a large red plastic cup over the light sensor to activate the light. After a couple minutes the light came on and as I happen to take my garage door opener remote up on the roof with me, I triggered the door opener several times with no resulting shutting off or even flickering of the light as before.

Since Monday and replacement of the bulb, the light has not been affected by using either the garage door opener or my shop vac at night. Usually a surefire method to trigger the light to shut off is by running my drill press with all my shop lights on although In running my 1/2 hp drill press press tonight, the light was unaffected, not even a flicker.

One thing I noticed, even though the new light bulb is the same specification, it's noticeably brighter than the old one.

Thanks to all for suggestions, etc
Mac