Recently I saw a plaintive tweet from @SalCan, Director of Product at Ziff Davis, asking “Where can I buy a Cree T8 LED?” Apparently there were none to be had. Strange, I thought — Cree just introduced them, and there initially seemed to be lots in my local Home Depot.
Now the reason behind the missing LED T8s is clear: Yesterday Cree voluntarily recalled the tube lamps because of a potential fire hazard:
“Electrical resistance between the spring contact and the printed circuit board (PCB) may cause over-heating due to electrical arcing. The printed circuit board can overheat and cause the LED T8 lamp to melt, posing fire and burn hazards.”
Well, this is interesting. Cree uses connectors quite a bit in its LED lights, likely because they are more reliable and work better in an automated assembly line. What’s the problem with the T8 lamps?
This is just a mere guess at this point, but it may have to do with the fact that, being a T8 replacement lamp, the LED lamp must work with the fluorescent fixture’s existing ballast. (T8 retrofit lamps require that the ballast be removed and the fixture direct-wired to the ac mains; the LED lamp’s internal driver handles all the power conversion.) With instant-start ballasts, which the Cree LED T8 lamp is compatible with, the ballast first applies a high (~600V) voltage to initiate the discharge arc. Perhaps for this particular spring connector, the high momentary voltage, under the right conditions, proved to be too much.
Here’s a photo of the spring clip connector and the pc board in the recalled lamp:
Cree estimated the number of lamps involved to be about 700,000; while they just recently went on sale at Home Depot to the consumer market last month, they have been sold through commercial channels since last fall.
Kudos to Cree for taking the initiative and pro-actively issuing the recall.