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David Gretzmier
04-03-2011, 06:13 PM
this thread harkens back to the days when steve p. would pose these questions. had something come up for the first time last week. I have solved the problem and know the answer- I'll let a few of you guys guess in and i will check in a few days.

installed 4 lights on one 12 guage circuit using Volt top dog spots. all spots are located about 100 feet from the trans. 2 lights, for 2 trees about 20 feet apart. each tree has one 20w 24d uplight mounted on ground, and one 35w 20d uplight about 20 feet up in the tree. king connections are made with the 25 foot leads aprox 15 feet apart. 13v tap on trans reads about 13.4.

the two ground lights and one tree mounted uplight work fine. all about 10.8- 11.1 volts. the last light reads voltage at socket, 10.9, but upon inserting the light, does not work. check again, reads voltage at socket. reinsert bulb, again, bulb does not light. I checked about 5 things before I found the culprit. anybody guess what the problem was?

S&MLL
04-03-2011, 07:42 PM
this thread harkens back to the days when steve p. would pose these questions. had something come up for the first time last week. I have solved the problem and know the answer- I'll let a few of you guys guess in and i will check in a few days.

installed 4 lights on one 12 guage circuit using Volt top dog spots. all spots are located about 100 feet from the trans. 2 lights, for 2 trees about 20 feet apart. each tree has one 20w 24d uplight mounted on ground, and one 35w 20d uplight about 20 feet up in the tree. king connections are made with the 25 foot leads aprox 15 feet apart. 13v tap on trans reads about 13.4.

the two ground lights and one tree mounted uplight work fine. all about 10.8- 11.1 volts. the last light reads voltage at socket, 10.9, but upon inserting the light, does not work. check again, reads voltage at socket. reinsert bulb, again, bulb does not light. I checked about 5 things before I found the culprit. anybody guess what the problem was?

Could be a number of things. We would have first checked the "new" lamp. Have taken mr16s out of box to many times that are bad. After that I would move right to the connection and put the pins of a mr16 right on the connection. If the light works there. Then your problem is the socket. We have had a few connections that pass volt reading on the meter but would not fire a lamp. Redo connection and boom.... Fires right up. Just because a socket has 12 volts doesnít mean a mr16 will fire up.


On a side note whenever we service a system that we didnít install we also dig up connections. Just to inspect the quality of the install. So many times around my area. I will see beautiful fixtures, nice s.s. Trans. And the connections are quick "discs" . 12 volts are able to pass through the connector but will not fire a halogen lamp.

starry night
04-03-2011, 07:58 PM
I haven't even gotten in the business, yet, but what the hey.

The obvious answer is a bad lamp. So.....that must be wrong?

David Gretzmier
04-03-2011, 08:11 PM
lamp was the first thing I tried. checked it for continuinity on the meter, beeped, then tried it on the fixture on the ground at base of tree. worked. but tried a new bulb anyway. no go.

Classic Lighting
04-03-2011, 09:41 PM
So you have 10.9 up to the socket but the lamp is dark?
On a side note, are there any fuses in the circuit?

steveparrott
04-04-2011, 04:28 PM
Could be a nicked lead wire going to that fixture (or a loose connection in the socket) (or a bad splice) - justs a few strands connected. With no load, the voltage is fine. With the lamp load, voltage drops enough so less than a few volts at the lamp.

S&MLL
04-04-2011, 10:43 PM
Could be a nicked lead wire going to that fixture (or a loose connection in the socket) (or a bad splice) - justs a few strands connected. With no load, the voltage is fine. With the lamp load, voltage drops enough so less than a few volts at the lamp.


Like haha


I tried explaining this in my post.

David Gretzmier
04-04-2011, 10:48 PM
no nicked wire, no bad splice. tested voltage at the splice and the socket again after checking bulb, socket, splices, trans, will light bulb at splice but still reads 10.9 at socket and will not light bulb, and finally narrowed it down to...?

steveparrott
04-04-2011, 11:27 PM
Need another clue.

David Gretzmier
04-04-2011, 11:35 PM
note that I have never seen this before. once I tested all the above, it has to be this.

David Gretzmier
04-04-2011, 11:57 PM
also, sorry, just noticed did not answer the above, no fuse inline.

PLSWest
04-05-2011, 01:01 AM
you ran lighter gauge wire to that fixture by accident...

David Gretzmier
04-05-2011, 02:02 AM
heading to bed, but wire lead was 16 guage factory wire for 25 feet from fixture to splice to 12 guage with king connectors.

steveparrott
04-05-2011, 10:32 AM
Still think there has to be poor connection somewhere - possibly with the socket wire - could be exposed and contacting the fixture body.

Alan B
04-05-2011, 12:19 PM
too much pregrease from volt factory? when the u shape of the lamp + pins is inserted it smooshes the grease so it oozes and creates a short.. but prongs fromvoltmeter don't ? disclaimer dave has not told me nor have we ever seen or heard this... just taking a guess.

excuse the poor typing... broke ribs and collar bone over weekend skiing with my 4 kids and using left finger.

steveparrott
04-05-2011, 02:31 PM
excuse the poor typing... broke ribs and collar bone over weekend skiing with my 4 kids and using left finger.


Ouch! I know the feeling - hurts to laugh. I pray for your speedy recovery.

Lite4
04-05-2011, 03:11 PM
Hmmm, I like Alans answer. Sounds goofy enough to be it. I would think you would have checked the socket to make sure it wasn't missing a contact on one side. Problem has to be with the socket. Missing metal side wall but the base is intact for the probes. Just guessing.

emby
04-05-2011, 11:50 PM
Well if you are reading 10.9 volts at the socket without the lamp and then you place the lamp in and it will not work it must be leaking voltage somewhere when the load is attached. Which means that the circuit is not completing. Loose connection, socket or shorting out on something. It would not surprise me to find out that one of the wires going to that fixture was partially broken and therefore could not handle the load of the lamp.
Have you tested the voltage while the lamp is in the socket? If so what is it?
Much like a faulty neautral in my world.

klkanders
04-06-2011, 12:19 AM
I would guess that while you were checking the connection you wired a temporary new socket in right there or did you just touch lamp to connectors?
I am siding with others who say the socket is messed up inside or its a bare or pinched socket lead wire.

David Gretzmier
04-06-2011, 07:26 PM
socket pins and spring were fine and wire was not contacting the body. socket lead wire was not "pinched" per se, but I am going to say that is the closest answer.

after finding voltage in both the wire nut connection and the socket, and the wire nut connection would light it at the 12g, but not the socket, I cut the lead wire in the middle of the run, about 12 foot from fixture, tested it, bulb lit, and it worked fine. wire nutted back together, and then cut about 6 foot from fixture and it was not fine. between the 6 foot from the fixture and the 12 foot mark, there were no marks on the wire, but replaced it and it worked fine. stripped the entire 6 foot run later on that evening at home, on one side the wire, about 18 inches in, wire had seperated to just a strand or two for about a 3 inch run. external part of the insulation showed no nicks or stretches. the other side of the wire was fine.

my guess is at some point in the manufacturing process something just went wrong with the wire or insulating process, and then corrected itself.

went back and heat shrink tubed the lead wire on tree.

I appreciate all the answers, and as these "stump the lighting guy" items come up I am happy to share them.

steveparrott
04-06-2011, 08:05 PM
Good challenge question - thanks for sharing it.

I think I did get the right answer in saying that it was just a few strands connected in a wire but never would have guessed it to be in the middle of the wire.

I have seen this happen in a transformer power cord, especially right next to the plug. That can happen if the installer bends the cord trying to close the GFCI cover.

Alan B
04-07-2011, 12:30 AM
d-

thx for sharing. usually wire has signs of damage--first time i've heard of internal wire damage with outside looking proper.

Steve thx for the kind words... i'm healing up pretty quick.

emby
04-07-2011, 12:33 PM
Thanks David for sharing with us,

I have seen this many times in the electrical field especially when stranded wire types are involved. I have been told that when they switch over to a new run there is a possibility of the connection being compromised. With wire types such as THHN or T90 you can slightly see a little bump on the skin of the wire where the connection has been made.
Good catch as it usually is the last thing you think of when trouble shooting.

Ken

David Gretzmier
04-07-2011, 10:45 PM
well, I'll be honest, had the light not already been mounted in the tree, I would probably have just replaced it and sent it for replacement to alan over at LLW. and although it sounds like a quick fix, I went through everything that folks mentioned her as I have seen all those things happen: bad brand new bulb, a bad connection at splice, bare wire grounded to fixture, nicked wires, bad sockets, pins, even an issue with where the socket wires are heat shrinked to the lead inside the fixture. I have seen leads that failed because of a broken connection inside the insulation and it looked stretched.

but since this was a new problem, I was stumped by this as well until I started cutting the lead wire.

and I will give steve partial credit. he was correct in just a few strands of wire, but I was looking for the middle of the wire. and I have never seen the trans cord do this, but now I know it can happen.

good responses all.

RLI Electric
04-08-2011, 07:28 AM
I have come across that is spools of romex before. I have also seen in romex where the jacket looks fine but the hot and neutral are fused together (short circuit) inside a normal looking cable. Tough to find these.