Mystery Fuse?

in Energy
16 replies 1.8K views


  • Kilty_2Kilty_2 Forumite
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    I'd have someone inspect the wiring - if it is in fact connected to another property this is obviously illegal....
  • zagfleszagfles Forumite
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    jc8 wrote: »
    Hmm, I didn't know it was this complex, I'm pretty oblivious to the plumbing system. I think its a 16amp fuse. I've done some reading on immersion vs gas heating, and I think we might plough on with the fuse off. It seems from a purely cost effective point of view, its the better option.

    16 amps sounds right for an immersion heater. That's almost certainly what it is. If you check the cylinder like I said you'd be able to prove it. Generally fuses would be 30 amps for a ring main (for plugs) or cooker, 5 amps for lights, 40+ for electric showers, and around 15 amps for an immersion heater. But yes best to leave it off, they use a lot of electricity if left on - only use it if your boiler fails.
  • CardewCardew Forumite
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    If you want to check if the fuse is for your immersion heater, leave it on for a couple of hours, without using any hot water, and check the monitor. The thermostat on the immersion heater will have switched off the power.
  • jc8 wrote: »
    The shared-circuit thing sounds worrying. It definitely doesn't connect to anything in our flat, have you ever heard of a confirmed case of one flats' electric meter powering a neighbouring property?
    An EDF Energy manager once told me it is far more common than you might imagine and is often due to shoddy workmanship by developer's electricians. That was just after he had established that my meter had been transposed with a neighbour's meter for the 7 years since the block was built.

    Who was the developer on your block? If their name begins with a letter between E and G, I would not be at all surprised.
  • macmanmacman Forumite
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    It's relatively easy to transpose a meter reference, but to run a circuit from a CU inside one property to another property is unlikely to be accidental.
    It's got to be a back-up immersion heater.
    No free lunch, and no free laptop ;)
  • edited 28 February 2011 at 11:24AM
    spirospiro Forumite
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    edited 28 February 2011 at 11:24AM
    jc8 wrote: »
    I just tested it by running all the taps and the shower until the water was cold, then left it an for hour with the fuse off.

    I've just turned on the water, and it's as hot as it ever has been, so it doesn't seem to be connected to the heater in anyway.
    While the water was heating up did your consumption jump by about 2500w? If so this implies, but does not prove, another fuse is for the immersion heater. If it did not jump then I suspect something other than elec is heating the water.
    If not the case already you need to clearly label each fuse i.e. upstairs lights, downstairs lights, downstairs ring main etc. Typically an immersion will always be on its own curcuit.

    If you dont get to the bottom of it I would invest a few quid in getting an electrician in to check things out and confirm what this mystery fuse does.
    IT Consultant in the utilities industry specialising in the retail electricity market.

    4 Credit Card and 1 Loan PPI claims settled for £26k, 1 rejected (Opus).
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