The LH0039 DM Technology 85849 is a G13 medium bipin base, non-shunted* lamp holder with flexible wings for slide on or push fit mounting. It does not have a locator post (post, stop, nib) that positions the socket on the fixture. The LH0039 T8 (G13 base) fluorescent or LED lamp holder has a rotary lock (turn and lock) insertion to keep the LED or fluorescent tubular lamps in a fixed position. It has a 16mm lamp axis (height above fixture pan to center of lamp). The DM Technology 85849 is rated up to 660W-600V and is cULus, CSA listed. The DM Technology 85849 has front quick connects that allows for easy installation of wiring. Used with rapid or program start ballasts and LED bulbs that require a non-shunted* lamp holder. It is made of durable polycarbonate.
*The primary difference between shunted and non-shunted lamp holders (also known as tombstones or sockets) lies in how the electrical current flows through them to the lamp pins:
Shunted Lamp Holders:
- Internal Connection: Shunted lamp holders have their two electrical contacts internally connected or "shunted." This means there's a single electrical path through the socket.
- Single Wiring Track: They receive voltage through a single set of wires that then spreads to both contacts that connect with the lamp pins.
- Continuity: If you test a shunted socket for continuity across its two contacts, a multimeter will show a closed circuit (it will beep or light up).
- Usage: Shunted lamp holders are typically used with:
o Instant start ballasts in fluorescent lighting. These ballasts provide a high initial voltage to start the lamp and require the pins at each end to be at the same electrical potential initially.
o Some plug-and-play LED tubes that are designed to work with existing instant start ballasts.
o Double-ended direct wire LED tubes: Although they can also work with non-shunted sockets, shunted sockets are an option.
o
Non-Shunted Lamp Holders:
- Separate Contacts: Non-shunted lamp holders have two separate electrical contacts that are not internally connected. This creates two distinct electrical paths.
- Dual Wiring Tracks: They require two separate wires (line and neutral) to connect to the two contacts within the socket. Each contact receives voltage independently.
- No Continuity: Testing a non-shunted socket for continuity across its two contacts will show an open circuit (no beep or light up on the multimeter).
- Usage: Non-shunted lamp holders are required for:
o Rapid start, programmed start, and dimming ballasts in fluorescent lighting. These ballasts preheat the lamp filaments, and each end of the lamp needs to be connected separately to the ballast.
o Single-ended direct wire (ballast bypass) LED tubes: These tubes receive power on one end only, requiring separate line and neutral connections to the non-shunted socket on that end. The sockets on the other end simply provide mechanical support.
o Some plug-and-play LED tubes designed to work with specific ballast types (like rapid or programmed start).
Link to T8 lamps that this socket fits