15 replies to this topic

[mdj]

Howdy,

 

Anyone know what the value of the fusible link should be on a UC ? I am guessing it was 100 amps. 

 

Had the starter motor out while dropping the transmission and noticed there isn't one at all which is dangerous and stupid and I will be fixing it as the car goes back together.

 

Matt

[RallyRed]

The older Toranas had a fusible link buried in the harness, hard to spot with a casual glance...UC not the same?

[mdj]

That part of the wiring seems to be replaced - there's two points on the engine harness connector that have been bypassed but you're right I should probably dig all the way through it to be sure. Certainly wasn't there 6 inches or so from the eyelet where I expected it.

[RallyRed]

Drawings seem to show it?
FYI
https://www.gmh-tora...wiring-diagram/

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[Rockoz]

The fusible link just looks like a bit of wire if that helps you out.

There is no fuse looking piece in the traditional sense.

 

Cheers

 

Rob

[IanC]

This is what it looks like on mine.https://photos.app.g...V4DR6dsnTye32eA

[rodomo]

LJ, purple wire is solenoid, Fusible link bolts on to starter with the battery cable.

  

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[Uncle Chop Chop]

Just for reference, it would be handy to know what it's rated at.

[Rockoz]

Going from some memory and standard cable ratings I doubt the main wire would be rayed at anything more than 40 amps.

The fusible link would have had a rating of around 20 amps rated current.

The idea of the fusible link is that it is able to carry the current of the wire it is protecting without any issues, but will melt well before the wire.

It is basically short circuit protection only.

If you have excessive draw below its blow rating, everything will still heat up and likely melt.

Once things melt enough, there might be a chance that there will be a short circuit and the link should blow.

 

Not the best form of protection.

 

Cheers

 

Rob

[yel327]

Probably rated not much different to the ammeter in a HK-HQ maybe? Although not all vehicle current runs through that.

[RallyRed]

While looking for rating data of the fuseable link, I stumble across the fact that the lighting switch has an internal circuit breaker/ overload unit...never knew that.

[mdj]

Here's the connection to solenoid. Perhaps I spoke to soon and the soft black section is the original fusible wire despite the newer termination ? Red main bus wire is so stiff it feels like it's solid core.

 

 

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[Uncle Chop Chop]

While looking for rating data of the fuseable link, I stumble across the fact that the lighting switch has an internal circuit breaker/ overload unit...never knew that.

 

 

 I unintentionally found the out nearly 40 years ago. But very handy at the time!

[Rockoz]

Yeah that soft black bit is the fusible link.

Sometimes they blow and there is no external indication such as burnt insulation.

Used to give the fusible link a pull test to ensure that it was intact.

Often the pull test would show that it had blown.

 

I think it may have been an ADR requirement for the headlights to have circuit breaker if the beams werent individually fused.

The idea being that if there was a short, the breaker would trip then reset hopefully giving enough light to get you safely stopped.

Had that issue once in a Commodore years ago.

I had fitted driving lights using the large New Era tin can relays.

The relay shorted tripping the headlight breaker. It reset fairly quickly. Did it a couple of times before I found somewhere to pull over.

Never used those relays again after that.

 

Cheers

 

Rob

[RallyRed]

Yeah that soft black bit is the fusible link.

Sometimes they blow and there is no external indication such as burnt insulation.

Used to give the fusible link a pull test to ensure that it was intact.

Often the pull test would show that it had blown.

 

I think it may have been an ADR requirement for the headlights to have circuit breaker if the beams werent individually fused.

The idea being that if there was a short, the breaker would trip then reset hopefully giving enough light to get you safely stopped.

Had that issue once in a Commodore years ago.

I had fitted driving lights using the large New Era tin can relays.

The relay shorted tripping the headlight breaker. It reset fairly quickly. Did it a couple of times before I found somewhere to pull over.

Never used those relays again after that.

 

Cheers

 

Rob

Amazing.. I had the same thing back in the 70s, LC GTR, New Era relay, Cibie Super Oscars. Lights out, back on again...never could figure out why. Was unaware of the integrated C/B.   Never happened again.

[claysummers]

Up to EK at least have a bi-metal contact points style circuit breaker in the light switch. No fusible link. Ignition circuit is unprotected. Don’t ask me how I know…..


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