Retrofitting a G9 light fitting to be not-G9.

Discussion in 'Electricians' Talk' started by Sansa, Oct 28, 2013.

  1. Sansa

    Sansa Member

    The plan is to retrofit this light with a transformer and then replace the individual G9 sockets on the light with G4 sockets.

    What I haven't yet found is a G9 sized socket that takes a G4 lamp. Anyone got any ideas? Are the screw positions on a G9 socket standardised?

    I'm also looking recommendations for some powerful G4 lamps.

    Thanks. I might make an Instructable of this if I manage it :)
    Last edited: Oct 28, 2013
  2. unphased

    unphased Screwfix Select

    Hi Sansa. What are your reasons for wanting to do this? Seems an odd thing to do?
  3. Sansa

    Sansa Member

    G9s all seem to be one of the following:
    • Expensive to run (Hallogen)
    • Enormous (CFT and LED)
    • Expensive to buy (Some LED)
    G4s seem to be the opposite. Small because the transformer goes in the light fitting (even the big ones are small). The LED lamps are cheap because there's no tiny transformer in each bulb, and they're cheap to run because they're low power.
  4. Lectrician

    Lectrician Screwfix Select

    • Both traditional G9 and G4 are halogen.
    • CFT and LED are larger in both types.
    • BOTH are expensive to buy if you for LED.
    G4s are 12v, derived from a transformer designed for halogen lamps, some wire wound ones outputting AC, but most electronic types outputting a high frequency. These are not designed to power LED replacements. You usually have to change the transformer for an LED driver (delivers variable voltage but a FIXED current depending on load). Known as constant current drivers. The LED lamps which say they are suitable for existing transformers mean wire wound ones (rare), not electronic, and the LED lamp has circuitry in them to limit the current rather than relying on a constant current driver.

    Not sure I would be bothered with replacing lamp holders my self, I would just not choose a fitting with G9s. My reason? None of your. Simply their lamp life is ****.
  5. unphased

    unphased Screwfix Select

    Hi Sansa. My advice would be to ditch the idea and look at LED mains voltage type lighting. It is definitely the way forward. LED technology is improving almost monthly and whilst they would appear to be expensive when compared to the old halogen type they are very very energy efficient because they use low power, typically 4W to 7W in a domestic environment. They have superior lifespan, anything from 10,000 hours to 30,000 hours or more and over the lifespan of the lamp prices will fall and you will be paying less for your energy bills. The alarming rise in enrgy costs should focus your attention on reducing energy usage. Personally I would rather invest a couple of hundred pounds fitting my house out with LED lamps than pay it to the energy suppliers. :) That's how to justify the expense.
  6. Sansa

    Sansa Member

    Actual LEDs that are powered by 240V? Interesting. Or just a unit that includes a transformer and has low-voltage LEDs in it? The latter is what I'm planning on building here, using the shell from a light fitting that I already have.

    I'm going to continue this project offline since I don't think anyone's paying attention to my actual question which I've now solved anyway. Plus Lectrician has mis-understood everything despite my very simple explanation in the paragraph in post #3.
    Last edited: Oct 30, 2013
  7. Lectrician

    Lectrician Screwfix Select

    Simple enough, but you're still reinventing the wheel.

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