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“I purchased a GE pre-lit Christmas tree in 2007. The lighting was composed of custom strings of clear Constant-on incandescent bulbs. Each string included 1, 2 or 3 groups of 49 constant-on bulbs and one fuse bulb in series. There was a total of 1200 bulbs on the tree. When a Constant-on bulb burned out, it shorted itself out so that the other bulbs in the substring would stay lit. The remaining bulbs just burn a little brighter. This is certainly preferred to having a substring of 50 bulbs go black. However, as more bulbs burn out, the stress on the other bulbs increases which reduces their life. In a tree with 1200 bulbs you tend to miss burnt out bulbs. These factors, plus the bulbs just getting older contributed to ‘avalanche” type failures in recent years. I’ve watched a substring all of a sudden get brighter and brighter and in a few seconds all of the bulbs in the substring have burnt out including the fuse bulb. It happens too quick to stop. You just have to keep up with the maintenance on these type trees.”

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