Do the simple and easy first to locate the problem by way of process of elimination.
First verify it’s the
fixture and not the
circuit.
Install this
fixture in another
circuit and another known to be working
fixture in this
circuit.
Second, Inspect the
plug.
Does it if
stage pin show any oxidation or melting on the pins? If
stage pin, are the slots in the pin parallel or pushed together. Shake the
plug and listen for rattles within it. Rattling of plugs on especially other than
stage pin means loose terminals within it.
Third, Inspect the
cord for damage.
Any rips or tears in it? Any crushing or anything else that draws your attention? Inspect especially where the cable enters both
plug and
fixture strain relief. This area especially less flexible by way of stranding heat
wire conductors will and do break down on in time. Less strands and less flexible ones at that located in an area where it’s clamped down yet can from that location rotate and
bend 180 degrees. Flex at this
point enough and the strands will break. Flex the cable than in a certain way and you will conduct. Flex it again and the wires no longer touch and you do not. This as with clamping too hard on conductors by way of improper
strain relief, or not enough clamping or use of a either failed
strain relief or one that clamps directly onto the conductors. I have at times on a 12/3 SJ cable that has about 1/16" of
conductor insulation, and 1/16" of outer
jacket insulation over the conductors, noted at times some gorilla clamping the
strain relief down too tight or using the wrong
strain relief setting. Such things are in each
plug’s instructions - a reason to actually read them. Force a 3/8" dia
cord into a 1/4" hole and yep it does hold. On the other
hand the only reason it will do this is all the soft material such as
insulation between conductors has been by way of pressure forced out of the way. In cases like this where not a failed
strain relief by way of not enough pressure, I have at times noted cables where there is only 1/32" of
insulation left between conductors or even after flexing, such conductors rub and cut away what’s left in
insulation and short. The insultion even if silicone is still softer and more easy to compress or move out of the way than copper. Too tight a
strain relief will cause conductors to short at the
strain relief. This as opposed to a
strain relief that was not tight enough and allows the outer
jacket to fail in pulling loose thus now having the sharp edges of a
strain relief to cut into conductors. This and allows all tension or fact conductors are still within the
plug to be reliant upon the clamping pressure of the
conductor screw terminals on the conductors of the
wire. How many pounds of pressure can a 18AWG
conductor take before it breaks? Verify it’s the proper
strain relief or cut and adjust it so it is now. This or add tape to bulk it up below.
(A better solution for both
plug and
fixture strain relief is to absorb and prevent some of the flexing able to be done at the clamp. A S-4
lamp cap is designed not to cut into the fiberglass sleeving where it clamps. Still on this and on especially other fixtures where you have the sharp edges of a two screw
strain relief bearing down on the outer
jacket and conductors, a double layer of ½” wide Scotch #69 fiberglass electrical tape on the outside of the sleeving will help protect the fiberglass
insulation from being cut into and prevent the cable from flexing right at the sharp corner. If you say first wrap the conductors with a double layer of tape by way of sliding the fiberglass
insulation away from the conductors, than while the tape is un-cut, slide the fiberglass
insulation back over the tape wrapped part, than do the double layer of fiberglass atop the sleeving, you now have four layers of tape preventing flexing too tight of the conductors and little to no chance the fiberglass sleeving will fail in pulling loose.
Same concept on the
plug end of the cable. Many plugs have sharp edges which will cut
thru both inner and outer insulators on cable. In this case there is a few ways to do it.
Friction tape while gooey is the traditional method. Don’t use it on the
fixture itself - it can catch on fire. As with the above, a double layer back and forth to wrap inner conductors under fiberglass sleeving, don’t cut it yet, slide the fiberglass sleeving over the coated area, than at least two more layers in burring the end of it under the
strain relief and you now have a rubberized gripping of the fiberglass sleeving on both sides of it which vary rarely fails if proper tension on the
strain relief. This also prevents too much flexing about a 90 degree angle at the
strain relief. Otherwise if you need to make up for a wider hole such as on old style Union
stage pin plugs, a few more layers quickly makes a 18ga heat
wire into that of a 12ga SO cable such a
plug was designed for. I have also seen the use of
Heyco flat cable
strain relief inserts used on this type of
plug for this application. Works well but does not
address the flexing issue that over time can cause problems with conductors breaking at the flex
point.
On the more modern
Bates style cable I have also seen use of a
cable tie/pan tie with a double wrap about it inside the
plug so given it’s tension that won’t pull
thru a
strain relief, it prevents as long as the
cable tie is tight enough it from pulling loose. For the most part with one
strain relief fitting on
flat and one in the round, the
Bates style
plug is sufficient in preventing the fiberglass sleeving from pulling loose. Otherwise a double layer of
friction tape under the fiberglass sleeving will be sufficient to by way of
friction tape, prevent the sleeving from coming loose.
Another option with cable that has other than fiberglass
insulation is to use vinyl tubing or outer jackets of larger sized cables sleeved over the primary cable’s outer
jacket. It prevents the cable from flexing so well and more distributes an even pressure over the entire surface of the cable. Say a vinyl tubing 2" long with a ID of 3/8" sleeved over that of a cable with a 3/8" OD than becomes say a cable with a ½" OD which now is optimum for many types of
strain relief.)
Fourth, take apart the
plug.
Look at the conductors, were any crushed by way of
strain relief or obstacle within the
plug? If
stage pin, was it using ferrules? Tug on the conductors, any pull free from the
terminal? Any conductors showing damage or frayed? Are the terminals tight? If
stage pin, are they using either
ferrule or
crimp?
(On
Bates style
stage pin plugs for a
fixture you are in the case of a old style S-4
Leko installing a 18ga.
wire within a 12ga
ferrule. Lots of room within the
ferrule to not put even pressure on all the conductors so as to cause resistance, and even more opportunity for the screw to cut
thru the
ferrule in than cutting
thru the conductors. At a minimum when installing 18 or 16ga wires into a 12ga
ferrule, they should be stripped twice as long, folded back upon themselves and than inserted into the
ferrule which makes it fill up the 12ga
ferrule a little more. This will make the 18ga
wire into a 15ga one within the
ferrule at least, and a 16ga one into a 13ga
conductor. Much harder given a lot of extra space otherwise for the screw
terminal to just cut
thru the
ferrule and the conductors. Otherwise there is more than just 12ga ferrules on the market and they are also available in insulated versions that wrap around the
insulation of the
wire in preventing it from fraying. The say 16 or 18ga insulated
ferrule will than fit within the 12ga
ferrule and first capture the
wire as intended, than with the 12ga
ferrule center it on the screw
terminal. The insulated part of the smaller
ferrule prevents the 12ga
ferrule from falling off and by way of now two ferrules, prevents the screw from cutting
thru a single layer of
ferrule. Better distributed clamping on the smaller conductors also. Best of all would be to in this case use a 18ga x .39" insulated
ferrule. Sleeve it with a non-insulated 16ga x .39"
ferrule. Sleeve this than by a 14ga .39"
ferrule, than by the 12ga x .35"
ferrule. This would make the 18ga
wire than become 12ga
wire at least inside the
Bates plug type
stage pin screw
terminal. Lots of layers of tin plated copper to distribute the pressure evenly on the
conductor but cut off what’s sticking out beyond the 12ga x.35"
ferrule so the screw makes pressure into the meat of the
conductor. That would be an expensive way of doing it, but work really well. Otherwise one
ferrule for the actual
wire gauge and one for the
ferrule set up for the
plug works well enough.)
(Same concept with ring or flag terminals on other types of
stage pin plug. There is lots of
wire gauges of each specifically designed with the same #8 screw size hole to match the
gauge of
wire used. Always either use the proper
AWG of
crimp terminal or at very least fold the
wire up sufficiently so it becomes close to that of the one available. In the case of 18ga
wire fitting into a 12ga
crimp terminal, if you fold it so there is three 18ga conductors
fitting into the hole, the 18ga
wire folded three times is now 12AWG in size. Using the proper Stakon type
crimp tool especially if the front cutting jaws are
ground off the tool for use on flag terminals and not some form of hammer, vise
grip or what ever to crush instead of
crimp is also necessary. A quick and good test is to
crimp a set of 12AWG conductors with your tool as if making a 12ga cable. Than screw those terminals to a wall. Climb that cable than. If it don’t support your weight, your
crimp was either too tight in breaking or if the conductors came loose, improperly crimped in not tight enough or not enough material was displaced. A
terminal properly crimped has a jaw on it which displaces material to within the cavity and not crushes it about the wires. Crushed about the strands of
wire allows some strands really tight, and others not so tight.)
Never unless the
stage pin plug was designed (an older intermediate but obsolete design) to be used without terminals or ferrules, install bare wires directly under a screw turning and cutting into conductors. This much less they will
settle over time and fall out of compression into the areas around the screw which have no pressure on them. This causes less strands of
wire directly under the pressure of the
terminal thus a smaller
conductor and resistance to
current. A problem waiting to happen and the same reason for using the proper size of
terminal or
crimp. Such terminals even on other than
stage pin where the strands of
wire settle a
bit will become loose to further this problem in having only a loose connection to the
plug - lots of resistance = listen for the rattle on any
plug you use though a
stage pin probably won’t rattle. Given it does not make noise it’s very important to always properly terminate the strands of
wire because there is nothing telling the next user you did a quick fix. On older Union types, it is not acceptable to simply wrap the conductors around the screw
terminal or tin the
wire in doing so. If you have the
wire wrapping washer fine (give me a source for them,) but otherwise always use the flag and shortened
ring terminal.
Never accept more than two strands of
wire that did not fit within the
terminal or
ferrule. Twisting the heck out of
wire does make it into a tight bundle but also makes it larger in dia. This could be acceptable say in
fitting a 12ga
wire into a 12-10ga
terminal, but for say a
ferrule that is sized for the non-twisted size of the
conductor, you now have made it into about a eleven
gauge conductor and it won’t fit so nice. Should you need to straighten a
conductor, instead twist some but more pull on it to do so. No more than a 1/4 twist to the
conductor. There is a tool out there also called a
ferrule crimper... really cool tool to have should you have the cash and intent to make a really good connection.)
Fifth have a look at the lamp.
Is the lamp good by way of
filament and
continuity? Have a really good look at it’s pins, it will indicate a bad lamp
base or contact to it. Others hearing popping and other noises out of a
fixture is that of hearing the lamp
base or something within the
socket arc welding as it conducts.
What do the pins look like? Nice shiny metal or oxidized and if not even melted? Put a good lamp into a bad
base and it will destroy the lamp by way of it’s contact pins. Put a bad lamp into a good lamp
base, and it will destroy that lamp
base. Never test a lamp short of having examined it’s pins and they look good into another
fixture’s lamp
base. This will only lead to destroying another lamp
base now. No pitting, copper showing or pock marks and or welded areas should be observed on a lamp.
How easy does this lamp pull free both from it’s holder and the sockets of the lamp
base itself? Too easy, or too hard? Too easy and possibly it’s holder and it’s sockets are both bad no matter what they look like. Too tight and it might be the case that the
base is out of alignment and by way of being difficult the lamp installed is installed at a slight angle and is also not making good contact. This beyond the
Altman stuck lamp in removal concept of the past, there is at times alignment issues making even a S-4 difficult to install lamp into
base. That difficulty in primarily installing the lamp, or in the case of once the lamp is installed how easy it comes out is of more importance than once installed how difficult it is to get out.
Allow the snapping and popping to exist long enough and your lamp realistically can weld itself to its lamp
base.
RSC (R-7s) lamps such as on
cyc lights or yellow construction work lights are the worst for this type of concept. Otherwise often on a off shore DC-Bayonet (BA-15d)
base, the solder contacts can melt around the contacts in making the lamp impossible to remove yet not work once the contact has melted away from it. In the mean time with such a
base type and cheap lamp, it could cause intermittent contact to the lamp.
For more normal fixtures, your
socket by way of it’s holder and the individual contacts should be sufficient to retain the lamp. If with a bump the lamp could fall out, it’s a shop lamp
base no matter what it looks like. A
PAR lamp should be able to be held only by it’s
socket or your lamp
base is bad. Same here with a G-9.5
base. Loose is loose and don’t conduct well no matter what it looks like. Was it the lamp, the
base or both? Attempt without powering up the
fixture to dry fit another lamp into it. Sufficient or does by way of tension this lamp
base fail?
Six, open up the
lamp cap.
Make sure you have your mica
insulator and no shorts in the wiring. A path of least resistance might not be by way of the lamp’s
filament. It could instead at times be by way of short you have not electrocuted yourself on yet. For one moment it’s working, the next it’s shorting to the
system which might or might not be sufficient to trip. If the
system has lots of resistance already, or the breakers are shot, such a
circuit might not trip but definitely be shorting even randomly.
Next check the condition of the fiberglass
insulation over the conductors as they go into the lamp
base. Should be tight about the
conductor and not expanded or frayed. Check also once inside the
lamp cap for any parts of the
wire that might have been pinched in also causing a short.
ETC with the NI-gold lamp
base socket terminals chose a fiberglass outer
braid insulated silicone
wire. That’s a good thing by way of protection of the
insulator but once it’s frayed or expanded, does nothing but show a problem underneath. Under this fiberglass sleeving is a silicone coated
wire which if it gets too hot will become brittle and flake or crack off. The fiberglass reflects heat away from it and protects against shorting if in decent shape but otherwise offers limited to no isolation. Other companies have added another layer of fiberglass spaghetti tubing over this
conductor and even have boosted the temperature
rating in the case of a S-4 up to 250c rated fiberglass braided Teflon insulated
wire. A
bit less flexible in
wire type by way of amount and size of strands making flexibility but also safer by way of temperature and quality of
conductor.
It’s often the case that someone will have removed the prevention pin from a 750w lamp and used such a lamp on a 575w rated
fixture. Such a lamp is safe enough to use for a limited period of time even on the 18ga
wire, the only problem is with the heat. In heat, the
insulation over the conductors will start to break away and even flake off where it’s hottest - where it’s entering the lamp
base.
If heat and shorting was not the cause, it’s probably in the contacts themselves. A good indicator is the lamp’s pins or now how well they retain the lamp. Even with a
wire collar about a
socket, it can still stretch over time and heat. Insert one
socket at a time on a lamp and
bounce the lamp held by it. Does it come loose? If so that lamp
base no matter what it looks like is bad. Any
socket no matter the type that freely allows the lamp to fall out is a bad lamp
base. Test the other
socket. Blackened or arched sockets must be replaced but otherwise one that allows the lamp to come loose is one step before the arching starts. On other types, too loose, yep you will get
snap crackle and pop out of it.
Seven value your time.
At some
point, your time is more valuable than that of the time spent in trying to save a
fixture. There is contact cleaners/lubricants available that will halp but on a G-9.5
base 9.53mm O.C and 3.17mm dia x 11.4mm long, there is not much you can do with either lamp
base or lamp which in solving for now won’t later waste your time on. A GY-16 or larger
base type, perhaps but the Medium 2-Pin is not worth the effort.
A new lamp is in the $15.00 range and making one that’s shot work, than spending your time troubleshooting if it don’t soon later is not worth the effort. Same with a similar price in contacts.
ETC I believe is no longer selling the old 18ga version. #W330-04 for the 16AWG
wire modern version will fit as an upgrade and now be rated as a
fixture for 750w no matter if alignment slot for 750w lamp has been drilled out or not. In fact the old style
Leko is upgradable to the new
lamp cap without dependant upon how old the
fixture, cutting away alignment pins or otherwise a direct fit.
Install new contacts and you without cleaning them find much less work now and in the future invested. A shame you can’t just
crimp on a new contact but the new ones while on a cable will also work well.
At this
point you should have a solution to what caused it or simply be replacing everything.
Step by step, but do the easy first.
