The other 100 amp fuse ?????????
Discussion
Driving along on Friday when the electrics went dead. Nothing, not even interior light. RAC man found some burnt out wiring in loom near battery.Cue rapid disconnection of battery, SH*T, it could have caused a fire!!!!
Car recovered to James Motor Sports near Ashford, me very cold!
After a sleepless night I went there on Saturday to see what the damage was.
I was worried because two days before I had fitted the Modwise Hot start relay kit and the wife was sure it was to do with that.
Very relieved when Chris Baldock said it was the 100 amp fuse, but NOT the one on the chassis rail.
??????????????????????
Apparently my Chim (a 200 450) has an additional 100 amp fuse fitted in the positive battery lead adjacent to the battery. I didn't know of its existence, Chris had seen it on a few cars before. Certainly not mentioned in the Bible.
The poor design means they gradually fracture, as the effective width reduces its gets hot resulting in the holder breaking and the circuit is broken. This explains the strange smell that my wife could smell when we went out in the car the other week. (She thought it was ME!)
Fortunately no other damage although Chris is going to check out the loom just in case.
He has found a different fuse holder on the Net of a better design which is being ordered, also I have asked him to replace the chassis mounted on with this type as I have always been concerned about it.
Much has been written about the advisability of checking/cleaning the 100 amp fuse, I would advise others to see if they have this fuse especially if its a late model, and check it carefully, it would be easy to replace on the roadside if a spare is carried.
With dead electrics and the windows closed I realised at once that if I shut the door from outside re entry would require the "secret" entry method, so it was fortunate that I had in the cockpit the necessary tool to do this. I will say no more about that!
It was lucky that on such a cold day I had adequate clothing to keep warm whilst awaiting recovery, although a decent torch is to be added to the contents of the boot, it was light when I went out but dark by the time the recovery wagon arrived, luckily I had been able to coast off the road into a car park (of a golf club, no jokes please from the Griff fraternity!).
Anyway, I hope that me writing all of this may save someone from a similar fate.
Edited by TVR keith on Monday 17th December 09:23
They are not a standard fitment: some cars don't have any, some just have the alternator fuse and some have both.
I do sell replacements including a MIDI type fuse which fits in the same holder but is encapsulated. This is more rigid and less likely to fracture.
Click here for details
I do sell replacements including a MIDI type fuse which fits in the same holder but is encapsulated. This is more rigid and less likely to fracture.
Click here for details
TVR keith said:
Driving along on Friday when the electrics went dead. Nothing, not even interior light. RAC man found some burnt out wiring in loom near battery.Cue rapid disconnection of battery, SH*T, it could have caused a fire!!!!
Car recovered to James Motor Sports near Ashford, me very cold!
After a sleepless night I went there on Saturday to see what the damage was.
I was worried because two days before I had fitted the Modwise Hot start relay kit and the wife was sure it was to do with that.
Very relieved when Chris Baldock said it was the 100 amp fuse, but NOT the one on the chassis rail.
??????????????????????
Apparently my Chim (a 200 450) has an additional 100 amp fuse fitted in the positive battery lead adjacent to the battery. I didn't know of its existence, Chris had seen it on a few cars before. Certainly not mentioned in the Bible.
The poor design means they gradually fracture, as the effective width reduces its gets hot resulting in the holder breaking and the circuit is broken. This explains the strange smell that my wife could smell when we went out in the car the other week. (She thought it was ME!)
Fortunately no other damage although Chris is going to check out the loom just in case.
He has found a different fuse holder on the Net of a better design which is being ordered, also I have asked him to replace the chassis mounted on with this type as I have always been concerned about it.
Much has been written about the advisability of checking/cleaning the 100 amp fuse, I would advise others to see if they have this fuse especially if its a late model, and check it carefully, it would be easy to replace on the roadside if a spare is carried.
With dead electrics and the windows closed I realised at once that if I shut the door from outside re entry would require the "secret" entry method, so it was fortunate that I had in the cockpit the necessary tool to do this. I will say no more about that!
It was lucky that on such a cold day I had adequate clothing to keep warm whilst awaiting recovery, although a decent torch is to be added to the contents of the boot, it was light when I went out but dark by the time the recovery wagon arrived, luckily I had been able to coast off the road into a car park (of a golf club, no jokes please from the Griff fraternity!).
Anyway, I hope that me writing all of this may save someone from a similar fate.
Edited by TVR keith on Monday 17th December 09:23
still i would rather have them,more fuses the better in my opinion,especially on this car.That Daddy said:
My car is the same,one on the chassis and one near the batterystill i would rather have them,more fuses the better in my opinion,especially on this car.
How often do you hear of electrical problems which have required the fuse to prevent a fire? I've never heard of a single one. On the other hand, mechanical failure of the fuse seems to be an every day occurrence, when they go bad it's always inconvenient and occasionally dangerous. IMO it's a self-inflicted problem best fixed by getting rid of the still i would rather have them,more fuses the better in my opinion,especially on this car.
thing altogether.I can understand the extra protection offered by lowly rated fuses, but 100a isn't going to prevent damage if something really bad shorts out - the only cable rated to carry anything like that seems to be the stuff that it doesn't cover. The big brown cables are 2x50a, and the 100a fuse will blow circa 200a IIRC.
Dave
Dave
GreenV8S said:
That Daddy said:
My car is the same,one on the chassis and one near the batterystill i would rather have them,more fuses the better in my opinion,especially on this car.
How often do you hear of electrical problems which have required the fuse to prevent a fire? I've never heard of a single one. On the other hand, mechanical failure of the fuse seems to be an every day occurrence, when they go bad it's always inconvenient and occasionally dangerous. IMO it's a self-inflicted problem best fixed by getting rid of the still i would rather have them,more fuses the better in my opinion,especially on this car. thing altogether.t as put the jump leads on the wrong way then you would be glad to have one inline,if the holders and fuses are maintained i cant see anything worth crying abouti have never had any problems with fuses, be it the Main fuse/s or Fusebox cluster,i grant you the one on the engine mount is prone to corrosion,thats not a fault of the fuse or holder, but the burke who sited it there
i will guarantee if you short the main power feed from the alternator to earth it will blow the mainfuse,whats wrong with that
Edited by That Daddy on Monday 17th December 18:33
How does the 100A fuse protect against reversed jump leads? If you're connecting two batteries together the wrong way round they're going to go bang, the fuse won't stop that unless you're connecting the batteries leads via the fuse (in which case, just where are you connecting these jump leads to?).
The only situation where I can see a benefit from the fuse is where the main power lead is physically damaged 'downstream' of the fuse. That's a pretty exceptional thing to happen hence my comment that it's something I've never seen or heard of happening. I imagine that somebody decided that this might happen in an accident and introduced the fuse to reduce the risk of fire from a battery short circuit. To me that seems like a very remote danger and not worth the unreliability and agro caused by these unreliable fuses.
The only situation where I can see a benefit from the fuse is where the main power lead is physically damaged 'downstream' of the fuse. That's a pretty exceptional thing to happen hence my comment that it's something I've never seen or heard of happening. I imagine that somebody decided that this might happen in an accident and introduced the fuse to reduce the risk of fire from a battery short circuit. To me that seems like a very remote danger and not worth the unreliability and agro caused by these unreliable fuses.
Later cars shifted the alt fuse inboard, alongside the fusebox feed fuse (not even implemented on early models - I suspect ThartDaddies is a mod), inside is a better location. As one of the earlier posts and Steve suggested upgrading to midi cartridge fuses as opposed to strip, as well as the better made Durite midi fuse holders, I have long advocated
This is the arrangement I have 're-engineered' but they will only protect me from doing something stupid I believe I can't see them doing much in normal operation - TBH I only installed them cos I wanted to join some big cables when re-routing my alt & fusebox connections
Dave
This is the arrangement I have 're-engineered' but they will only protect me from doing something stupid I believe
I can't see them doing much in normal operation - TBH I only installed them cos I wanted to join some big cables when re-routing my alt & fusebox connectionsDave
I recently hired a 3.5 ton Luton van and that had big fuses everywhere including a 500A one protecting the starter motor. It is becoming more and more common to add high current fuses to protect the high current circuits. The 500A fuse failed and left me stranded. Apparently these fuses are dealer only but at least they were all located on top of the battery...
BTW the fire at Bristol Avenue in the 1970s was rumoured to have been started by an electrical fault that shorted out the battery and set a car alight. That eventually destroyed most of the factory.
BTW the fire at Bristol Avenue in the 1970s was rumoured to have been started by an electrical fault that shorted out the battery and set a car alight. That eventually destroyed most of the factory.
Fell foul of this one today while at the MOT station. Just been through emissions, brake test and lights all OK. The guy then moved the car out to put over the pit when it stopped dead with no power but a wisp of smoke from the passenger footwell. If that wasn't bad enough it was no outside with both windows down and rain just starting to pour. Kindly the guys opened up their spare garage and pushed her inside so I could see if I could see what was wrong. Checked the main 110 amp fuse down by the starter motor but that was fine, now where???
Into the footwell battery box slid back and eureka another 100 amp fuse. Not sure why it blew, in fact it melted one end of the holder so new holder required. Managed to cobble up a spare 100 amp fuse and limped home to sort.
At the time it blew I think the MOT guy had every electrical item switched on and the fan motors running :-(
New holder ordered today, also will need to get the lead from the battery to the holder replaced as it did melt the cable coating at that end of the fuse holder.....
Into the footwell battery box slid back and eureka another 100 amp fuse. Not sure why it blew, in fact it melted one end of the holder so new holder required. Managed to cobble up a spare 100 amp fuse and limped home to sort.
At the time it blew I think the MOT guy had every electrical item switched on and the fan motors running :-(
New holder ordered today, also will need to get the lead from the battery to the holder replaced as it did melt the cable coating at that end of the fuse holder.....
This fuse will only protect the bit of wire between the fuse and the fuse board and the internals of the fuse board.
All circuits (other than the main starter circuit) are protected by their own fuses at a much lower current rating.
That main cable gets a pretty hard life as it gets bent and twisted. The additional connections are a potential weak link if they start to degrade.
I guess that the connector worked loose, the resistance increased and it cooked.
Think I'll go and check mine!
All circuits (other than the main starter circuit) are protected by their own fuses at a much lower current rating.
That main cable gets a pretty hard life as it gets bent and twisted. The additional connections are a potential weak link if they start to degrade.
I guess that the connector worked loose, the resistance increased and it cooked.
Think I'll go and check mine!
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