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Technical The Main Fuse

Discussion in 'The Hokey Ass Message Board' started by squirrel, Jun 13, 2021.

  1. spanners
    Joined: Feb 24, 2009
    Posts: 1,178

    spanners
    Member

    Allthreads are lower amperage.
     
  2. X-cpe
    Joined: Mar 9, 2018
    Posts: 1,153

    X-cpe

    One of the nastiest jobs I ever had was caused by wrapping a fuse with foil. Lighter fuse kept blowing (also controlled the dome light and, I believe, the radio). Back of the dash was all charcoal and extinguisher powder. Owner could have saved a lot of heartache by emptying the ashtray so the overload of butts wouldn't hold the lighter in when he closed the ashtray.
     
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  3. davidvillajr
    Joined: Apr 4, 2005
    Posts: 1,003

    davidvillajr
    Member

    Sometimes it’s the “little things” that count.

    yeesh!
     
  4. Cosmo49
    Joined: Jan 15, 2007
    Posts: 1,237

    Cosmo49
    Member

    "I have a couple of those little square breakers with the round terminals..."

    Squirrel, or anyone, could you post a picture?

    Thank you.
     
  5. squirrel
    Joined: Sep 23, 2004
    Posts: 48,733

    squirrel
    Member

    I'll borrow a pic from ebay of one I bought for the car....

    I noticed that you can buy new ones that have the "ears" pointed the wrong way, towards the center. That's one problem with Chinese copies...sometimes they just are wrong.

    breaker.jpg
     
  6. upspirate
    Joined: Apr 15, 2012
    Posts: 2,273

    upspirate
    Member

    Maybe for the shorter fuses?
    There were some short ones, forget what they were called
     
  7. squirrel
    Joined: Sep 23, 2004
    Posts: 48,733

    squirrel
    Member

    The short ones like SFE fuses are for low current applications, you wouldn't replace a 4 or 7 amp fuse with a 20 or 30 amp breaker.
     
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  8. lostone
    Joined: Oct 13, 2013
    Posts: 1,632

    lostone
    Member
    from kansas

    Yep I would install a new fuse, and during broad day light take it out for a ride and turn everything on and see if you have any problems. If you do atleast it's daylight and you will be able to see to stop safely.

    If you can run her a good haul with everything on and no problems I'd mark it up to a used and tired fuse, even I have those days where I can't seem to pull my load.
     
  9. G-son
    Joined: Dec 19, 2012
    Posts: 775

    G-son
    Member
    from Sweden

    May be worth mentioning that a fuse doesn't blow instantly as the current reaches the number on the fuse. It may take hours for the fuse to blow if the current is exactly the same as the fuse value, and the time goes down as current goes up. So it may be a good idea to measure the actual load with everything on, if it's close to the fuse value some reengineering of the system is in order.
     
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  10. Budget36
    Joined: Nov 29, 2014
    Posts: 6,423

    Budget36
    Member

    I guess a guy could wire up an ammeter and verify the current draw easy enough.
     
    G-son likes this.
  11. X-cpe
    Joined: Mar 9, 2018
    Posts: 1,153

    X-cpe

    A new car get ready man would. Car came up, ticket read " tail light fuse blowing". After removing seats and carpet and finding nothing, pulled the dash light fuse . There in place of the 5 amp fuse, that fed the dash lights from off of the tail light/parking light fuse, was a 30 amp fuse. Problem, missing dash light bulb in a metal socket allowing wire to ground out.
     
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  12. SS327
    Joined: Sep 11, 2017
    Posts: 266

    SS327

    When I worked at a dealer dimes in the cigar lighter was the biggest problem. Old people who buy Buicks liked to put change in ashtrays and then remove the lighter element. That was the number one fix for blown dome lamp fuse.
     
  13. squirrel
    Joined: Sep 23, 2004
    Posts: 48,733

    squirrel
    Member

    I put change in a baggie in the glove box, and I put ear plugs in the ash tray. And plug the phone into the lighter socket, on road trips.
     
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  14. lippy
    Joined: Sep 27, 2006
    Posts: 5,533

    lippy
    Member
    from Ks

    Start smoking. :)
     
  15. 57tailgater
    Joined: Nov 22, 2008
    Posts: 713

    57tailgater
    Member
    from Georgia

    I had a '65 OT car once that would do the same thing. Periodically driving at night - BANG - ALL would go dark and engine would quit. There was one fuse that kept blowing but I never figured out what exactly caused it. It didn't happen frequently enough and I wasn't smart enough at the time to figure it out. So I just kept spare fuses with me. But, I would know what happened when it did happen so I at least had that comfort. Replace the fuse and all was back to normal. Until the next time........ ;)
     



  16. Should I use metric or SAE?
     
  17. G-son
    Joined: Dec 19, 2012
    Posts: 775

    G-son
    Member
    from Sweden

    Metric for precision, SAE for convenience.
     
  18. '34 Ratrod
    Joined: May 1, 2019
    Posts: 70

    '34 Ratrod
    Member

    I had an OT van that all of a sudden, while driving, ALL the lights would come on extremely bright, flash off and on, and then go off. It was possessed!! I talked to a repair guy at the dealership, explained everything going on and he laughed. He said you have a penny in your cigarette lighter hole. Sure enough there was a penny in there rattling around causing the "possessed" problems!
     
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  19. davidvillajr
    Joined: Apr 4, 2005
    Posts: 1,003

    davidvillajr
    Member

    Heck, go Whitworth and have the best (worst?) of both. :D
     
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  20. squirrel
    Joined: Sep 23, 2004
    Posts: 48,733

    squirrel
    Member

    I got the 30 amp breaker in the mail yesterday...NOS Wagner, made in USA, stamped on it. I put it in to replace the 20 amp main fuse.
     
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  21. Words of wisdom passed along to me by a former GM Tech Center Electrical Trainer: " There are NO intermittent electrical problems, just intermittent SYMTOMS. The problem exists whether it is displaying symptoms right now or not".
     
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  22. TrailerTrashToo
    Joined: Jun 20, 2018
    Posts: 955

    TrailerTrashToo
    ALLIANCE MEMBER

    That breaker has a large moment arm for vibration (At my age, the only moment that I can calculate is a "Senior Moment" ;)). I had a blade style 30 Amp breaker in an OT 1975 Scout II, the vibrations eventually tore-up the sockets in the fuse holder - the intermittent connection resulted in some truly impressive backfires at 75 MPH. Expanded the muffler case a couple of inches...

    I fabricated a small sheet metal clip to secure the circuit breaker in position. Sorry, no pictures found on my computer, a crude "word picture" (less than 1,000 words) follows:

    Breaker end of the clip goes over the top of the breaker - Imagine a hand clasping the top of the breaker - Thin layer of rubber between the breaker and the clip to dampen any vibration.

    The firewall end of the clip (imagine an elbow) is bent 90 degrees, has a hole and is screwed into the firewall with a self-tapping screw. Length is adjusted to lightly compress the rubber at the breaker end of the clip.

    Russ
     
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  23. Ebbsspeed
    Joined: Nov 11, 2005
    Posts: 5,492

    Ebbsspeed
    ALLIANCE MEMBER

    The only thing that a dirty ground and a high load have in common are excessive heat. The above comment has been addressed in several other posts.

    Editorial comment: Current flows from negative to positive.

    More likely due to excessive current.

    But the heat generated by that poor connection can melt the solder in the ends of the fuse causing the fuse to go open, or heat the fuse element up enough that it's resistance increases, causing more heat, causing more resistance, ad nauseum, until the fuse element separates with an accompanying arc.

    90% of HAMBers are afraid of Ammeters. I'm not counted in that guesstimate, and never will be.
     
  24. Whitworth will only work with Lucas electrics...
     
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  25. SS327
    Joined: Sep 11, 2017
    Posts: 266

    SS327

    Joe Lucas the prince of darkness!
     
  26. G-son
    Joined: Dec 19, 2012
    Posts: 775

    G-son
    Member
    from Sweden

    Well... Partly right. ELECTRONS flow from negative to positive. Back in the early days of electricity we had no way to figure that out, so we just started calling one side positive and the other negative, and said that electricity flow from positive to negative. So if you are in a physics class you say that electrons flow from negative to positive, if you are learning electricity you still say that electricity goes from positive to negative.
    99,999% of the time it really doesn't matter, so we still use the original version when we talk about electricity.
     
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  27.  
  28. squirrel
    Joined: Sep 23, 2004
    Posts: 48,733

    squirrel
    Member

    I've encountered fuses that had lost connection at one end, presumably because the contact got warm enough from resistance, that it melted the solder connecting the end cap to the fuse metal.

    That's not what's going on in my case.
     
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  29. Ebbsspeed
    Joined: Nov 11, 2005
    Posts: 5,492

    Ebbsspeed
    ALLIANCE MEMBER

    Science trumps theory every time.;)
    Those positive ground cars from the first half of the previous century might have been built that way because of electrical science instead of conventional theory.
     
    Blues4U likes this.
  30. While correct power travels from negative to positive .

    either way is considered correct when discussing practical electrical.
    Or at least that’s how it was taught to me years ago.
     
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