Fuse box Replacement

[Colin Lindsay]

It's okay, I've mended it to destruction anyway. Rather than resleeve the cable I decided to replace it, cut off the old one, and now the solder won't stick to the terminal, and now the other wire to that terminal has come off and won't stay back on... I hate these things. I've also burned my finger on the soldering iron and have a large blister. Anyone got hand cream?

Thank the powers that be for the spares pile; I have another GT6 motor that had broken the park mechanism, so between the two I now have one that runs as a single speed motor - no idea why but a) it's not blowing fuses any more and b) it's better than none. That should please the MOT man if they're still testing in April. 

BUT: back to square one; started the GT6 up today to get the coolant circulating and the fuse blew again, or else had blown since yesterday. Half the dashboard stripped out already, down to three replacement fuses, and one week to MOT.

[s99sdp]

Sorry for dragging this topic out of the darkest depths. I've recently had an auto electrician round to replace my fuse box for a blade version (I replaced it previously with a new glass fuse holder and wasn't happy) and while he was there he diagnosed an issue with the dash lights and put some additional earths in for me for safety.

 

The old fuses were 35a, he's left 3 30a blade fuses in the new box. I've put led bulbs into the dash lights and intend to slowly swap led bulbs all around in time but here's the question.

Should these three fuses still be 35a, should I source some new ones and swap out the 30a he left in?

 

I'm always honest on here, I'm not clever, I don't understand electrics hence why I had this guy in to do the work so shall I swap these out for 35a?

 

Thanks in advance 👍

[johny]

I would leave the fuses as they are, the new 30A items should be fine. The wires are rated above that current so those fuses will always prevent them from overheating and burning which is your worst fear. A smaller fuse would give more protection to your wiper motor for example which, if starting to seize, would draw more current so the damage to it could be reduced if the fuse blows sooner. However for this to work properly each electrical component in the car should have its own fuse which just isnt practical. 

An alternative would be to calculate or measure the maximum current draw on each of those three fuses and then fit a fuse with a suitable rating which presumably is what Triumph did in the beginning. Of course if you change the headlight for LEDs the current draw will be less on that part of the circuit and you could use a smaller fuse but do you really want to get involved in that and having to use different size fuses?

[s99sdp]

19 minutes ago, johny said:

I would leave the fuses as they are, the new 30A items should be fine. The wires are rated above that current so those fuses will always prevent them from overheating and burning which is your worst fear. A smaller fuse would give more protection to your wiper motor for example which, if starting to seize, would draw more current so the damage to it could be reduced if the fuse blows sooner. However for this to work properly each electrical component in the car should have its own fuse which just isnt practical. 

An alternative would be to calculate or measure the maximum current draw on each of those three fuses and then fit a fuse with a suitable rating which presumably is what Triumph did in the beginning. Of course if you change the headlight for LEDs the current draw will be less on that part of the circuit and you could use a smaller fuse but do you really want to get involved in that and having to use different size fuses?

Thanks johny, I'll just leave it as it is then. 👍

[dougbgt6]

The old fuses are not the same as the modern blade fuses the old fuses are 17 amp running, 35 amp blow, they are not supposed to run continuously at just under 35 amp.  The loom wiring is not rated for that current, more like 17 amp. So with 30 amp blades I would be anxious if they were running at near 30 amps. 

There is a lot of discussion and explanation about this at the very beginning of this thread. 

Doug

[Colin Lindsay]

3 minutes ago, dougbgt6 said:

The old fuses are not the same as the modern blade fuses the old fuses are 17 amp running, 35 amp blow, they are not supposed to run continuously at just under 35 amp.  

I have a drawer full of 35amp glass fuses; when I needed them for the GT6, suppliers were ignoring my request for 17amp continuous 35amp blow and just sending me 35amp. I'll use them eventually, just hopefully not as frequently as last Summer...

[s99sdp]

There is indeed a lot of info here but I don’t understand it because I’m not the sharpest and after being diagnosed with cancer during lockdown I have an issue with two masses in the frontal lobe of my brain that causes me to struggle with concentration and focusing on things so that’s why I was hoping for a clear answer as I’ve read a fair bit and I still can’t get it.

that’s why I just asked if I needed to swap the 30 amp fuses the electrician left me with for 35 amp.

im assuming now is should really swap them out for 35 amp? 

SP

[Colin Lindsay]

I use what I call dual-purpose fuses, or 17/35s - they run at 17amp but when the current reaches 35amp max they blow. By that time they're usually red hot. 

If anyone else needs some, I buy from this supplier for my GT6, pack of five:

https://www.ebay.co.uk/itm/5-35A-17A-CONT-CAR-AUTO-AUTOMOTIVE-GLASS-CARTRIDGE-VINTAGE-MOTOR-FUSE-6-3x-31mm/291022081317?hash=item43c2448d25:g:vKEAAOSw~BxdFkO8

For blade fuses... I don't know the exact tolerances of modern fuses but would 17amp work, or would it be better with some slight room for error ie 20 amp?

[s99sdp]

2 minutes ago, Colin Lindsay said:

No; you need what I call dual-purpose fuses, or 17/35s - they run at 17amp but when the current reaches 35amp max they blow. By that time they're usually red hot. 

I buy from this supplier for my GT6, pack of five:

https://www.ebay.co.uk/itm/5-35A-17A-CONT-CAR-AUTO-AUTOMOTIVE-GLASS-CARTRIDGE-VINTAGE-MOTOR-FUSE-6-3x-31mm/291022081317?hash=item43c2448d25:g:vKEAAOSw~BxdFkO8

Hi Colin,

I've had the old fuse box swapped out for new one with spade fittings as I mentioned earlier.

Do  I need the 35amp in the spade version?

 

Regards

 

SP

[dougbgt6]

SP,

Sorry to hear that, I have a lot of trouble with concentration and focusing, but it's usually down to Bingham's IPA 

What were saying is they should be running at around 17 amps or less. But on occasion you may get a surge, windscreen wipers on a sticky windscreen, A spike when you turn the headlights on.

The original 17/35 amp fuses are expensive, but blade fuses are cheap. 

In your position I would buy a box of assorted blade fuses, 30 for £2.50 on Ebay. Start with 20 amps, turn everything on, if something blows replace with a 25 and so on. 

Keep them in the car, you may need them when it gets dark and starts raining!

Doug

[s99sdp]

50 minutes ago, dougbgt6 said:

SP,

Sorry to hear that, I have a lot of trouble with concentration and focusing, but it's usually down to Bingham's IPA 

What were saying is they should be running at around 17 amps or less. But on occasion you may get a surge, windscreen wipers on a sticky windscreen, A spike when you turn the headlights on.

The original 17/35 amp fuses are expensive, but blade fuses are cheap. 

In your position I would buy a box of assorted blade fuses, 30 for £2.50 on Ebay. Start with 20 amps, turn everything on, if something blows replace with a 25 and so on. 

Keep them in the car, you may need them when it gets dark and starts raining!

Doug

Thanks for this Doug, that makes complete sense, even to me. 

I feel very inept sometimes as things that I would easily learn and pick up like this just don't stick and no matter how many times I read things it's like I haven't read it at all sometimes. I'm lucky though, other people didn't manage to get treated during lockdown so I'm definitely counting my blessings.

fyi, I don't take my car out in the rain 😆but now I've had the electrics fixed I can go out at night without fear off the dash going up in smoke again ☺️

Thanks again, off to ebay for some fuse shopping.

 

 

SP

[johny]

Let us know what you find as a suitable rating would be good to know. One thing when testing though is to make sure you wait a while with everything turned on as fuses work with heat so their blow time depends on the current flowing AND the time needed to generate the temperature required to melt the fuse wire.  I think 10 minutes should be enough....

[dougbgt6]

1 hour ago, s99sdp said:

fyi, I don't take my car out in the rain 😆

I'm with you there SP my wipers only get to work at the MOT. And then you have to think about the effects of sunshine on the paint work, it's a minefield. my car only did 5 miles last year. 

Doug

 

[s99sdp]

1 hour ago, dougbgt6 said:

I'm with you there SP my wipers only get to work at the MOT. And then you have to think about the effects of sunshine on the paint work, it's a minefield. my car only did 5 miles last year. 

Doug

 

5 miles? 😮

Mines done about 200 just bombing round the back lanes of Northamptonshire.

I need to get on with the interior but I think I’ll get a mobile carb man to pay me a visit and get it tuned up as it’s running quite rich atm

[SpitFire6]

Hi,

 I heard a myth about Triumph glass fuses having different ratings to other similar fuses.
Always thought that a fuse rating was its continuous rating @ a specific temperature, plus around 10% for an ATO fuse. Go above 110% & it will blow. ms to hours, depends on the design curve. Any body have the curves for a "Triumph" fuse? Suspect nothing unusual.
Headlamps are fused in a Triumph? I thought only the flash was?

Cheers,

Iain.

 

[daverclasper]

1 hour ago, s99sdp said:

I’ll get a mobile carb man to pay me a visit and get it tuned up as it’s running quite rich atm

Hi. If you want to get someone else to look at the carbs (If they are standard, then pretty simple to sort out and tune mostly, plenty of info on the web and on here), then if possible, I would look for an old school guy, who worked on these in the past and has a good rep.

Plenty of folk out there ready to take your your money and not care at all (or am I too cynical?).

Dave   

Edited February 6, 2021 by daverclasper

[johny]

No curves but quite a good explanation:

https://mgaguru.com/mgtech/electric/et102.htm#:~:text=The Lucas fuse (and most,blow instantly at 35-amps.

[SpitFire6]

9 minutes ago, johny said:

No curves but quite a good explanation:

https://mgaguru.com/mgtech/electric/et102.htm#:~:text=The Lucas fuse (and most,blow instantly at 35-amps.

He states that a 17A fuse blows at 35A. A 35A fuse will not blow at 30A. I cannot see any thing new there? I see a fuse marked Blow amps which is an odd spec to carry when no time implied.

 

[johny]

9 minutes ago, SpitFire6 said:

He states that a 17A fuse blows at 35A. A 35A fuse will not blow at 30A. I cannot see any thing new there? I see a fuse marked Blow amps which is an odd spec to carry when no time implied.

 

I think what it means is that a normal fuse which blows immediately at 35A will also blow at say 8A but over a much longer time period.  A slow blow fuse is designed to blow at the same instantaneous current but will withstand a much higher current below that (up to 17A) without ever blowing...  

[s99sdp]

3 hours ago, daverclasper said:

Hi. If you want to get someone else to look at the carbs (If they are standard, then pretty simple to sort out and tune mostly, plenty of info on the web and on here), then if possible, I would look for an old school guy, who worked on these in the past and has a good rep.

Plenty of folk out there ready to take your your money and not care at all (or am I too cynical?).

Dave   

I’ve heard there’s a set up guide on here somewhere, I’ll have a search

[Colin Lindsay]

15 hours ago, SpitFire6 said:

Hi,
Headlamps are fused in a Triumph? I thought only the flash was?

Cheers,

Iain.

 

Herald 1200 has no fuses at all; 13/60 has one in the headlamp flash. That's all! 

[johny]

yes in the good old days you used your nose to protect electrical circuits and components🤗

[SpitFire6]

2 minutes ago, johny said:

yes in the good old days you used your nose to protect electrical circuits and components🤗

Yes, PVC is the worst followed by; glycol smell, clutch material smell, brake friction material  smell, gearbox oil smell, oil smell then petrol smell.
Fun to smell at night prior to losing all the lights. 

[johny]

Must admit Im quite impressed with Triumphs 50 yr old electrics in general. On my car everything is original and Ive had very few electrical problems either with wiring or components. In fact the wires are still flexible, with neither the copper nor insulation having gone brittle and the only issue developing is that those tube type connectors are falling apart if I pull out the bullet connectors.

Oh and the only other problem Ive found is the dash push-pull main light switch internal springs have disintegrated and the contacts are burnt inside👍 

[dougbgt6]

I think "What were they thinking?!!! "

The bizarrely designed fuse box, constant trouble and the reason for this thread in the first place.

Fuse on the instrument and side lights, but not the headlights. Why?!!

The night dimmer relay! Why?

The GT6 heated rear window, mine is remarkable, it still works! Not many do.

Doug