Help finding fuse supplier UK? (Urgent)

Discussion in 'General Electronics Chat' started by Dyslexicbloke, Oct 11, 2011.

  1. Dyslexicbloke

    Thread Starter Active Member

    Sep 4, 2010
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    Hi folks,
    I feel a little silly asking this but ....

    I blew my multimeter fuse last week and cant find a replacement.
    Checked RS, CPC, Maplin and eBay with no luck.

    The meter is Maplin branded so tracking down the actual manufacturer would be a challenge

    The failed unit is a Holly branded:- HC10aR0.63

    It is a cartridge type 10mm X 38mm

    Which in general terms is a semiconductor protection fuse (That's FF isn't it?)
    Rated at 630mA, 1000V, 50KA

    Anyone know where I can buy some of these, online?

    (I would be happy with a slightly lower value if needs be but I cant even find that right now.)

    I'd appreciate you insight and suggestions as I am a bit stuck right now.
    Thanks
    Al
     
  2. SgtWookie

    Expert

    Jul 17, 2007
    22,182
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    Multimeter fuses are sort of "odd ducks", as they must have very high voltage and current interrupt ratings that a typical fuse won't have. That's because the meter is usually being held in the hand of the person using it, making the safety factor critical. If the fuse can't interrupt the circuit, a plasma ball can instantly form which is extremely hot and dangerous.

    The only place that I could think of you to contact is Fluke in the UK.
    http://www.fluke.com/fluke/uken/about/contact/default.htm
    Fluke makes the best DMM's. They are not cheap, but they will last for many years even if abused. If you cannot find a fuse of a proper rating, obtaining a Fluke meter would be a very good choice.

    I don't know if Fluke will allow you to purchase a fuse for use in a non-Fluke meter. Their online fuse selection guide goes by Fluke model number. It does give specifics about the fuse size, but in many cases does show the current and voltage ratings.

    I have seen some Fluke fuses rated for 630mA, but have not seen one rated for 1kv at this point in time - but I have not made an exhaustive search.

    These Fluke fuses are NOT cheap. It is difficult to engineer/manufacture a fuse that will reliably break a high voltage, high current arc that will also fit in a fairly small space.
     
  3. tom66

    Senior Member

    May 9, 2009
    2,613
    214
    These fuses *are* cheap - after all, the meter is a cheap Maplin unit.

    http://www.ebay.co.uk/itm/10-x-630m...al_Components_Supplies_ET&hash=item5acf8b4e3b

    This is a 250V fuse. A 250V fuse can only interrupt a 250V circuit. If you're confident you won't be using over 250V it should be fine.

    You can use a Fluke fuse, but it's overkill. Even if the fuse can interrupt 50kA, there's no certainty the multimeter won't blow up doing so.

    I have blown up a multimeter fuse by accidentally measuring 200mA current on a 230V AC line. The fuse was destroyed (not shattered though), the meter mostly survived, although I'm not sure if its accuracy drifted.
     
  4. SgtWookie

    Expert

    Jul 17, 2007
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    Tom66,
    Those are 5x20mm, DB needs 10x38mm. Twice the diameter, and nearly twice the length. Those won't fit.
     
  5. t06afre

    AAC Fanatic!

    May 11, 2009
    5,939
    1,222
    I would also think a lower rated fuse then it come to voltage. May work as a at least temporary fix. As long as you do not measure on circuits with higher voltage than the voltage fuse rating. Se if http://www.littelfuse.com/ has UK based vendor for fuses made for measuring devices.
     
  6. paulktreg

    Distinguished Member

    Jun 2, 2008
    611
    120
    Could you make do with 440mA? Rapid sell a specific multimeter fuse here rated at 440mA, 1000V & 30kVA. It's 10mm x 35mm but should fit. Granted it's a little under-rated but at only £5.41 it's worth a shot?
     
  7. debe

    Well-Known Member

    Sep 21, 2010
    946
    184
    10X38mm HV fuse is whats used in Microwave ovens in the HV supply. I have several in various values for repairing microwaves. can post a picture tomorrow if you want to see what they look like.
     
  8. Dyslexicbloke

    Thread Starter Active Member

    Sep 4, 2010
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    19
    Thanks so much folks .... all looks like good info.

    I would be happy to de-rate somewhat 440mA as opposed to 600mA but working is better than only working on the 20A range as it is now.

    I will buy the one from Rapid I think and then do a little more digging with the other info you have all supplied.

    I find it irritating that Maplin would sell the instrument and not the spare fuses, its not like we don't all make mistakes occasionally, I might complain a bit to them.

    Fuses for microwaves ... interesting, Google I think.

    I do occasionally work on 415 phase phase circuits and the inverter drives in some of the micro hydro installations I look after can have DC bus voltages in excess of 600, although I have never had cause to get anywhere near one.
    (I wouldn't trust the cheep probes at that potential anyway)

    Off to buy a fuse from Rapid and do a little more digging.
    Once again, thanks
    Al
     
  9. debe

    Well-Known Member

    Sep 21, 2010
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    184
    These are the 5KV Microwave oven fuses. To get them apart the end caps need to be split on one side with a fine hacksaw as shown. They come in 600Ma to 1A. They are $6.75 ea.
     
  10. debe

    Well-Known Member

    Sep 21, 2010
    946
    184
    I also have used these fuses in my multimeters. They are ceramic tube with a flame retardant powder inside & are used on the mains input of a microwave oven. They are designed not to shatter with a dead short on the mains. This can happen with a malfunction in the door interlock switches. Price is .80 - .83c ea.
     
  11. Dyslexicbloke

    Thread Starter Active Member

    Sep 4, 2010
    420
    19
    Hi D it was a good thought and very much appreciated but I checked out the HV fuses you suggested and discovered that they all seem to be T types.
    Time delay or slow blow whichever you want to call them.

    The units I am looking for need to be FF (Fast Fast or Ultra fast) so that they protect the electronics in the meter.

    I have sent a couple of emails to manufacturers and decided to get the 44mA unit from Rapid in the mean time.

    Thanks for all the help folks.
    Al
     
  12. orbiter

    Active Member

    Jun 17, 2010
    58
    3
    You could try Siba uk too. I saw them whilst looking for fuses for my Agilent meter, but ended up getting them from Agilent direct as they were cheaper, that took three weeks though :(

    Anyway.. Siba could be worth a try. Looks like it could be £7 delivery though if they've got what you need.

    http://www.sibauk.co.uk/
     
  13. Lundwall_Paul

    Member

    Oct 18, 2011
    220
    19
    If you must use a sub. The rules are overvoltage and under current
     
  14. SgtWookie

    Expert

    Jul 17, 2007
    22,182
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    That's part of the specifications. You also need to use the correct timing; ultra-fast, fast, standard, or slow-blow.
     
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