Normally the wiring to the
fixture is only a 90c
wire - easily with use overheats, becomes brittle and flakes off when moved. If you have that problem with the
ground wire you also have it with the conductors which is dangerous. Often a
fixture cooling thing - for me it’s always a question of how such a thing got its UL listing in that I never use 90c
wire near a lamp over at most 100
Watt - if even then and if then its fiberglass sleeved.
None the less, I prefer to see my
ground wire go bad before I see a
conductor go bad - good indication of something bad with the others to correct. Something to also look at is the rubber gland part of the
strain relief - it don’t take heat that well also and once brittle, the little teeth of the plastic
strain relief often do terrible damage first to outer
jacket than conductors in cutting
thru them with use.
The
ground screw is what it is - metric, probably varnished or some sort of
thread locker to keep it in place, no worse than a riveted
ground in both not so sufficient in how I do stuff.
Possible the
ground wire has been touching the lamp and over heating but normally
ground wires are fairly short in going direct to the
ground screw.
Good you are using the Sylvania
PAR 1
socket - best on the market in my opinion & bypassing the
barrier strip - another common problem with cans for patching the 90c
wire into the
socket is often another
point of failure. This especially with screws coming loose or screw tension or tension of sharp edges of screws clamping down on the bare strands of
wire instead of
ferrule covered strands.
So now for your conductors, you no doubt have a fiberglass sleeve coated 200c silicone
wire which goes out the
strain relief (you check) by way of outer
jacket #0 fiberglass sleeve to the
plug. Only improvement there - after if necessary changing strain reliefs when the rubber fails is to perhaps add a dual wrap of #23 fiberglass electrical tape around the outer
jacket fiberglass sleeving to prevent as it were chafing at the
strain relief. The sleeving prevents cut
thru, prevents the
whip from flexing as tight an angle at the
strain relief and in general is a good thing. Just a
bit of it overlapping the
strain relief by about a half inch for a one inch width in a dual or tripple layer (ends of the tape inside the
strain relief.)
So you have a straight run of the
power conductors to the
plug, only a question of what to do on the
ground. This ADJ type screw and or the other brands that
rivet their grounds to the can often are problematic in that while they are not persay loosening (It’s metric by the way thus why it might be stripping on you), but the
ring terminal on them in combination with the softness of the aluminum might allow the
ring terminal to get loose. Always a good thing to check on
safety inspection - can you turn it?
Replacement of the
ring terminal - typically a 8-32 screw for a
ground is preferred. 6-32 is undersized. Never use Nylock nuts inside a lighting
fixture - the nylon of the lock
nut has an operating temperature I believe I remember maximum of 175F, and after that it’s much like the
jacket of the 90c
wire in becoming brittle and or not functioning as designed. Never also use
thread locker on the threads of a
conductor - they reduce conductivity. Also, black oxide coated fasteners in coating don’t conduct as well and often also tend to corrode with heat and moisture. Stainless don’t conduct as well also but does take the heat really well, plus has a harder
rating.
For the
ground screw, I tend to in general use an actual grounding screw. Them green 10-32x5/16 hex washer head screws. Easy to figure out what it is, its coating helps conduct, easy to install given a 5/16" head when used with a 3/8 hex head of the
nut. Two
nut drivers tightening the screw as opposed to questionable tension able to get with a slotted or phillips screw
driver. All sorts of screw type in the
ground screw, I prefer those that are thread forming instead of thread cutting because of the
nut used. I typically use a 10-32 18-8 stainless steel top lock
nut with such a
ground screw or if necessary for conditions an external tooth lock washer attached zinc plated steel
nut. With the top lock
nut - sometimes the ding in the threads is not sufficient - toss such ones out, don’t attempt to use them if they don’t sort of stall while installing them. Same concept with the screw, once used with the thread deforming
nut, do not re-use once removed.
Should you use zinc plated steel toplock nuts - which might also be fine, toss them also after first use in being a
bit softer than stainless. This is a concept for electrical connections or fittings in general though not to say for normal fasteners in say having a 1/2-13 screw and side or top lock
nut. A
bit less thread deforming going on with say a 1/4" screw than with a #10 screw but milage might vary also in noting that a deforming screw is in a way stripping its way onto the screw thus by way of deforming it, kind of stripping it in a way. Something to keep an eye on with both
nut and fastener in tension as similar to that of a nylock
nut in telling when its bad. Loose enough to
hand thread, bad. In doubt toss it, but in general = the Stainless Steel
nut of a
ground screw combination will often be fine for a second use, the lower grade screw will be toast.
General concept in doing small screws with thread deforming nuts. Often good to do a harder class with a softer class or at least two of the same class - normally really bad to do two harder class in the same
bolt combination. Normally say for a 1/2"
bolt - hopefully at least, you are using a Gr.5 screw with a Gr.2
nut. Normally you are using say a zinc plated screw with a stainless steel
nut. Can use the reverse but should never do stainless with stainless = they don't thread well. This as similar to say doing grade 5 with grade 5 in thread deforming - they will just tear themselves up. Don't attempt to do a thread deforming screw in #6 size unless a brass screw at most. Just too small against the resistance to work dependably unless hardened or stainless screw with normal zinc plated gr.2
nut. Instead, better next best option would be a
nut with external tooth lock washer attached for high temperature applications or that of a normal
nut with added lock washer. Side lock nuts are as similar to external tooth lock washer lock washers in general better but if all that's available... it's a good thing in being better at least for high temperature conditions than a nylon insert
nut.
But as with any nylock or other type of lock
nut, that’s a good thing, but do add a external tooth lock washer to the mix to keep it honest. External tooth lock washers have more gripping
power than internal tooth ones one would use only in situations where the head of the screw or
nut is not sufficient to take advantage of the gripping
power of the washer. These types over that of a spring lock washer any day.
Frequently I’ll do two external tooth lock washers, one under the head of the screw, the other directly under the
nut, but at least one under the
nut is a good plan. I normally use zinc plated steel external tooth lock washers for a
ground, silicone bronze for high heat for a
conductor otherwise especially under a brass screw. If desired, a
thread locker coating,
varnish coating or glue can be added to the threads after the connection is done but not before. Shouldn’t be necessary but can be done.
On ring terminals, vinyl coated ring terminals - see above with nylock nuts have the same temperature
rating. Vinyl as opposed to nylon has a melting and or flame
point rating the same and as opposed to becoming just brittle and flaking off might become liquid plastic inside the
fixture. That’s doubtful but if you want, either get un-coated ones or grab
insulation and
ring terminal into two sets of pliers and yank the coating off. For a
ground a normal believe its zinc plated copper
ring terminal is fine to use. For higher temperature/lamp
socket installation only use high temperature ring terminals however.
The insulated
ring terminal has its uses in keeping together any fiberglass or
jacket on a
conductor where its stripped but otherwise the above high temperature tape can be wrapped around
barrel of
terminal/sleeving of the
conductor joint in holding all that together. Three wraps is fine. This especially might be important if you have a SF-2 fiberglass coated silicone heat
wire ground wire in use where it’s going to fray where stripped otherwise.
Not commonly available but can be dipped / dyed this SF-2 to be a
ground wire. For the
ground wire however in following the above concept of I want to know when I have a problem with my main conductors with heat, I often will do 150c Type K, FEP
wire so it melts down way before a
conductor will. This much smaller FEP also allows me if I wish to use a much smaller size of fiberglass sleeving over
jacket such as 1/4" or say a #2 vinyl coated in size. Often such a solution if not just the vinyl coated sleeving helps prevent against wear on the sleeving.
Otherwise FEP or SF-2 be it braided or without in Teflon or silicone is fine for a
ground. Could go 18ga for the
ground on a
PAR 56. Could also go 18ga of the lamp
socket also but the
stock 16ga
PAR one
socket is fine overall. Quite a few
PAR 1 sockets manufactured and available with different
wire gauges and coatings plus
wire lengths.
Finally on the
crimp tool. Remember just as with
wire rope clips to “never saddle a dead horse”, with a
crimp, never put “the seam into the saddle.” This means that on a “Stakon” type
crimp tool that has a jaw and a recess side, never put the seam of the
crimp where metal is bent together into a tube shape to hold the
wire into the side that gets the jaw. Seen it way too often even coming out of factories and they always fail. For this
gauge of
wire, a Klien #1005 would be correct as an example. Also, don’t use
crimp tools that crush instead of displace material. Note on the jaws of the above #1005 tool there is both the rounded tool part and the tooth jaw. Don’t use the rounded jaw ever - all it does is smash which is useful for prepping or rounding out a 1/16"
wire rope crimp to where you want it before the
Nicopress tool but otherwise for our business fairly useless even with insulated
crimp terminals. All you are doing is smashing the
terminal - it still has the same circumference overall. Such a “insulated
terminal”
crimp jaw relies on the concept of a less strands per
conductor wire such as
THHN building
wire that don’t persay give as easily as a multi-strand
conductor that like grains of sand can
settle about and under
current and expansion/contraction
settle a
bit more. The jaw displaces material within the
crimp terminal thus compresses the overall size a
conductor will have room to
settle into. Always good to use the jaw just make sure its not putting the jaw into the seam of the
crimp or its toast.
Further, once the
crimp is on, leave the tool there and tug with the tool on that
crimp hard. This will tell you if you have sufficient pressure - a thing of practice and leverage - often one
leg of the tool setting on the table while the palm of your
hand pushes on the other side. This concept especially useful for high temperature terminals.
The right tool for the ... Should you be concerned about the jaw having displaced material
thru an insulated
terminal, some electrical tape,
heat shrink or high temp tape over the
barrel or
insulation of the
terminal will sufficiently insulate over the exposed area. Much better to have a good
crimp than to worry about a recess in it that could short should something get into the hole. For a
ground... grounds are supposed to be the path of best short so un-insulated is fine.
That’s my solution for doing a
ground. Green grounding screw in 10-32, s.steel top lock
nut, a external tooth lock washer or two and a properly crimped
ring terminal. This plus the FEP.
, about electrical tape in PARs. (Had one go up in flames at a wedding rehearsal, the flame didn't go out after the 
