Help with fuse box fuse

Discussion in 'Electricians' Talk' started by Tony Freeman, Dec 28, 2020.

  1. Tony Freeman

    Tony Freeman New Member

    Wylex 32A SP TYPE B PLUG-IN MCB (87979),0 single pole, 230V AC, B curve, 3kA MCBs. BS EN 60898.

    After an accidental short in my small flat, I find that the fuse blows often
    If I put on too many heaters or the kettle, it blows, but it did not before.

    Is it worth replacing the above fuse? Could it have become damaged when the circuit blew from the short?

    Thank you
  2. terrymac

    terrymac Screwfix Select

    Do you have any electrical testing equipment ? If not ,you need an electrician to investigate .
  3. Banallsheds

    Banallsheds Well-Known Member

    You said it was a MCB now you’re saying it is a fuse. Which is it?
  4. MGW

    MGW Screwfix Select

    Although in my old house the [​IMG] MCB was protected by a RCD, this is unusual, so when such a fault exists I would say it needs testing, as they rarely go faulty, however it is normal for a fuse board with these to also have either another same size for cooker, or one of these [​IMG] for the immersion heater, seem to remember blue will plug into red but red will not plug into blue, since so easy to swap or change and we are trying to isolate due to covid19, although normally I would say get an electrician due to covid19 why not try temperature replacing? Under normal use the 16 amp blue will run a ring final.

    Only thing a 16 amp would not run is a shower, and not found any showers that are 32 amp so would need new consumer unit anyway to work a shower.
  5. MGW

    MGW Screwfix Select

    Don't be so pedantic, we know the box which takes these devices was designed as a fuse box, because you mix and match fuses and MCB's it does not change the name of the box, it is still a fuse box or distribution unit, it is not a consumer unit since when they were made there was no type testing, so yes correct to say it is a MCB fitted to a fuse box.
    Tony Freeman likes this.
  6. Tony Freeman

    Tony Freeman New Member

    Thanks for the responses.

    The fuse for the imersion heater is the same as for the electric circuit, but says B16 instead of B32

    I could try just swapping them over, to test the fuse.

    Can you tell me the difference between B16 and B32 - does this matter?


    Wylex Single pole, 230V AC, B curve, 3kA MCBs. BS EN 60898.
  7. AnotherTopJob

    AnotherTopJob Screwfix Select

    Assuming I have read this correctly, your previous fuse was 32A but the replacement is 16A, which explains why it is blowing.
    Replace it with the correct rating and it should be fine.
  8. Tony Freeman

    Tony Freeman New Member

    I am sorry, perhaps I gave the wrong information, I have not changed the fuses.

    The fuse for the plug circuit is .

  9. FlyByNight

    FlyByNight Screwfix Select

    Possibly you have damaged it.

    the 16 and 32 refer to the "fusing value" so 16A and 32A. You CANNOT change them over, for two reasons, safety and second they will not fit as the underlying socket is a different size. SF stock them both and the are pull out and replace - with power OFF.
  10. Bazza

    Bazza Screwfix Select

    32Amp is the correct device (MCB) for that circuit, assuming the circuit is a ring final.

    If the MCB keeps tripping there’s probably three reasons. I will list them from most to least likely
    1. At certain times you have too many heaters, kettles etc on at the same time. The MCB is rated at 32amp. Some heaters are 13A, a kettle may be 10amp+ so two heaters and a kettle adds up tomorrow than 32 amp!
    2. The MCB is out of spec in some way. You could try a replacement. Screwfix sell them
    3. There’s a fault somewhere, but everything is ok most of the time, so it’s unlikely. You’d need an electrician to decide this last option for you.
  11. Tony Freeman

    Tony Freeman New Member

    OK thanks for the info!

    I'll try replacing the MCB, they aren't expensive.

  12. Banallsheds

    Banallsheds Well-Known Member

    We are not talking about the box we are talking about the “things” plugged into it. He first said it was a MCB and later said it was a fuse. So my question still applies.
  13. Banallsheds

    Banallsheds Well-Known Member

    Ah so now we know. They are NOT fuses. They are MCBs. Correct terminology is important.
  14. Tony Freeman

    Tony Freeman New Member

    Take it easy man.
  15. Bazza-spark

    Bazza-spark Screwfix Select

    You have encountered our forum pedant, although he denies his own mistakes etc.
  16. Arthur Dent

    Arthur Dent Member

    Our resident pedant is also prone to do this;

    FlyByNight likes this.
  17. Banallsheds

    Banallsheds Well-Known Member

    As a new member read and learn, don’t criticise those with many more years experience than yourself.
  18. Banallsheds

    Banallsheds Well-Known Member

    There is nothing pedantry with using correct terms.
  19. Comlec

    Comlec Screwfix Select

    Speaking of the use of correct terms

    Power in loft - Is this allowed

    Now go and sit on the naughty step until you agree to play nicely with the other kids.
    Bazza-spark likes this.
  20. Bazza-spark

    Bazza-spark Screwfix Select

    Like your reference to ring main for a ring final the other day.

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