What Bulb For
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Why is half my string of Christmas lights out?

Look in the dark section for a twisted bulb or a failed fuse bulb. On GE’s mini sets with fuse bulbs, the bulbs run in circuits of 50, each with one fuse bulb, and when a fuse bulb fails its whole circuit goes dark.

What’s out?

Part of the setOne section is dark, the rest lightsThe whole setNothing lightsOne bulbThe rest of the set still lights

What to check

Check the dark section’s bulbs

On GE’s mini sets, a twisted bulb or a failed fuse bulb puts part of the set out.

  • Push each bulb in the dark section straight into its socket, without twisting.
  • On GE’s sets, the fuse bulb is the one with a white ring. Replace it only with the set’s own spare fuse bulb.

See also

Christmas light fusesC7 vs C9 vs mini bulbs
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What to check

GE’s checks for a set that doesn’t light

In order: loose bulbs first, the fuses in the plug last.

  • Unplug the set at the outlet.
  • Starting with the first unlit bulb, gently push each bulb base firmly into its socket. Don’t twist it.
  • If the set still doesn’t light, take out each bulb and check for lead wires out of place.
  • Open the fuse door and check the fuses.

See also

Christmas light fusesC7 vs C9 vs mini bulbs
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What to check

Replace it soon

On GE’s mini sets with fuse bulbs, the rest of the bulbs should stay lit when one burns out.

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Mini replacement bulbs
  • Use the set’s spares, or a bulb with the volts and watts the set’s instructions give.
  • GE’s instructions say burned-out bulbs put extra stress on the rest of the circuit, which can make more burn out early.

See also

Christmas light fusesC7 vs C9 vs mini bulbs
Start over

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Unplug the set before you touch any bulbs.

Why one section goes dark

A 150-light GE set of this kind has three circuits. On GE’s sets, steady and fuse bulbs aren’t interchangeable.

Common questions

Why do my lights go out after I move them?

On GE's sets, bulbs can work loose in their sockets in transport, which breaks the circuit between the bulb and its socket.

Is a fuse bulb the same as the fuse in the plug?

No. On GE's sets, the fuse bulbs protect each 50-bulb circuit, and the plug has its own fuses as well.

Keep going

Christmas light fusesC7 vs C9 vs mini bulbsHow many light stringsIndoor or outdoor lights

Where we get our information from

The circuits, fuse bulbs and checks come from GE’s own instruction sheets for its mini light sets. Checked against published data from GE.

See all 2 sources
  • GE mini light set instructions, models 61515LO and 61516LO (Nicolas Holiday, 2025): set watts, end-to-end maximum, amps times 120, fuses, GFCI outlet outdoors
  • GE 50, 100 and 150 light mini sets with fuse bulbs, instructions IM-56 (Nicolas Holiday, 2021): fuse bulbs, bulb ratings, 50-bulb circuits

General guidance from manufacturer and standards data. Products vary, so check the label and the maker's instructions.