sizzling sockets batman

[wyreman]

any idea why these sockets after these workhorse ballasts should be failing in record numbers?


it is the workhorse 5 and two f54 lamps

nominal 120v

the fixtures are pretty well enclosed.

I'll do some thermal imaging later this week.

The ballasts were never screwed into the enclosure. Apparently they were glued in at the factory.

Some of the fixtures are on dimmers, but I can't believe that there are any workhorse ballasts in there.
I haven't taken the fixtures after the dimmers apart yet.

Some sockets had loose wires, but that could be because... they were melted!

What should I be looking for, what could be overdriving these ballasts, causing such heat at the sockets?

lack of grounding? could that do it?

dimmers... sure

temperature? enclosed fixture

loose wires at the sockets, cheap sockets

 

[GoldDigger]

any idea why these sockets after these workhorse ballasts should be failing in record numbers?

What should I be looking for, what could be overdriving these ballasts, causing such heat at the sockets?

lack of grounding? could that do it?

dimmers... sure

temperature? enclosed fixture

loose wires at the sockets, cheap sockets

Just looking at the photo, I do not see any clear evidence that ballast heat started the whole thing off. Rather that the charring on the ballast housing came from heat at the socket.
If the spring contacts in the sockets lose their elasticity at high temperatures, or have other reasons for reduced contact pressure, that might have been the start of the problem. If the sockets are rated for the type and power lamps used, they should be OK though, as long as the lamp pins were clean at installation and the lamps were installed securely.

Are these sockets the type where you slide a bi-pin base fully into the slot and then rotate 90 degrees to make the connection to the shielded contacts? Is there a noticeable detent at the 90 degree point? If not, the tubes may have been under or over rotated leaving the contact points insecure. Once resistive heating or arcing starts, it will just get worse.

 

[wyreman]

just a whole bunch of bad sockets??

just a whole bunch of bad sockets??

yes, the ballasts are still working in the majority of cases.
if the ballasts are just glued in there, could this be a cause of overdriving the sockets
should I tap a hole for the ballasts anyway?

the sockets look just like this
http://semperlite.com/products/lampholders/main.php?PR_ProductID=706

there is no temperature rating i can see there
maybe i will just have to drill a few holes in each fixture...
I would drill thru the UL label but I saw no name or label there:angel:

I've seen lots of trouble w t5 fixtures, but usually the dimming kind.

 

[wyreman]

bypass the socket and it works great!
but it looks like it happens on a regular basis.
gotta try drilling some holes in there and grounding the ballast
the old ballast was just glued in there.

 

[wyreman]

pigtail

pigtail

might be better to pigtail a wire to each socket rather than shunting thru those cheap springs
http://horse.fulham.com/wiring-diagram-results/

thats where the problem keeps happening, where the yellow starts under the little spring.
looks like i can wire them better in parallel than in series here as long as they are shunted already

 

[kwired]

If not, the tubes may have been under or over rotated leaving the contact points insecure. Once resistive heating or arcing starts, it will just get worse.

My best guess at this point, bad contact will result in heating/arcing.

 

[Col Klink]

My best guess at this point, bad contact will result in heating/arcing.

Agree. Lamps are not seated properly in socket causing arcing...... Change the sockets...