More of the Southport Road Trip!

Tech Tips

Inside Richard & Marilyn Graham’s home: Enjoying refreshments, car talk, and telling some tall tales!

Parking outside the restaurant on the ICW in Southport!
 

Inside the restaurant 

The first article issues:
To sum the information that was printed in the first article, the fuses supplied from Triumph were built to conform to British Standards (BS) for wire protection, NOT standards in the USA commonly known as UL/CSA for Underwriters Laboratories / Canadian Standards Association. British Standard Fuses basically conform to European Electrical Standards commonly known as International Electrotechnical Commission (IEC) Standards.

These standards organizations all have different ways of specifying the fuses that are used in their respective parts of the globe, mainly because the wires the fuses are designed to protect are not the same physical size in the size and composition of the wire; or the size, composition and type of the insulation actually covering the wire. As an example, BS wire might be 0.1 mm of wire cross section measurement where UL wire might be 0.1 inch of wire cross section. You should know that a millimeter and an inch are not the same units, so the protecting device (fuse) needs to be designed for the differences.

Lost? Well unless you are an Electrical Engineer or technician, do not feel bad. After all, this is a science, an electrical science that people go to the university then gain experience for a good part of their life before mastering. Tell me SOMETHING I can Understand please!
Some electrical basics 101: Current is energy measured in units called amperes or amps. This energy translates into heat when it "flows" hence the word "current". Remember that current is energy and translates into heat. I won't go into volts, loads or resistance, but you do need to know that volts are what gives the current the ability to flow. The more volts, the more ability or potential for current flow and the potential for more heat. Lets stop there.

Lets see if I can get this fuse thing to a simplification of the base problem and parts. There are a myriad of fuses out there that will physically fit in your LBC.

The little glass fuse with the paper inside:
Originally, your Triumph was supplied with a small fuse with metal ends and a glass cylinder center piece manufactured by Lucas Electric. Inside the glass was a tiny piece of paper that said "Lucas" with two number ratings of the fuse, and a wire to carry the current. It measured approximately 1.125 inch long and about 0.20 inch in diameter.

The first number rating right after "LUCAS" is the number in amperes (current) that the fuse will "open", "blow" or "interrupt the current". In the paper fuse examples here above, you see a LUCAS 50A a LUCAS 35A, two no brand 35 amp with paper inside, a Clear Hooters 25 amp. The second rating in the Lucas style fuse was a number followed by the words "amps continuous" In the picture examples, you see 25 amps continuous, 17.5 amps continuous. This is the real important information, because that is the current rating of the normal use of the wire going to your Triumph accessories like your headlights, radio and instruments. Remember this second point for a few minutes.

Fuses of the Colonists:
Back in the USA, we have the AGC / MDL little glass fuse with no paper inside (LittleFuse, Cooper/Bussman, what-EVER!), and a 35A AGC stamped on the side of the metal cap.

So, the first time something in your Triumph wiring went bad, it blew a fuse and maybe you had no instrument lights or tail lights, or headlights, or radio. Commonly, you may have stopped by an automotive supply store like PEP Boys with the blown fuse in your hand and the counter person gave you a box of these AGC fuses with the same rating as the bigger number printed on the Lucas fuse paper. If that happened to be 35A, they gave you an AGC 35 fuse to put in its place. After all, it looks like it fits in the clips, and the numbers are the same, so okay, you buy it. It is only $1.00 for the box anyway. This was the first mistake, because remember, USA fuses are designed to UL/CSA specifications. They protect DIFFERENT size wire, wire your LBC does not have in it. Remember this second point for a few more minutes.

Pardon me but don't "interrupt" me while I am working!!
Okay, so now you have power again to your lights, radio, etc and drive happily down the road. Next you start to smell plastic burning. If you were wise, you immediately stopped the car, turned off the ignition, jumped out and disconnected the battery ... right!

More probably, you kept driving, and your wiring ended up doing the job the fuse was supposed to do, that was "interrupt" the circuit, and your lights went out again. If you were even more unfortunate, the wire was in an area where there was additional things to catch fire, and you noticed flames and or heavy smoke. "Damn Lucas wiring" you screamed disgustedly and you ran for some means to put the fire out.

So why did this happen?
Well, remember the second point that the Lucas fuse we used as an example was a 17.5 amps continuous / 35 A. The Lucas fuse would carry those 17.5 amps all day long, and if the current exceeded 17.5 amps approaching 35 amps, it would "open" "blow" or "interrupt" the current flow to protect the wiring so it could not exceed 35 amps.

And remember the third point that you replaced the fuse with an American UL/CSA AGC 35A fuse? Well, that little fuse was working away, doing exactly what it was designed for, allowing up to35 amps, (and a little more like even 10-20% more) through the wire in your LBC, the very same wire that is not supposed to carry that 35 amps.

Now remember that current flow translates into heat, and the more current the more heat? That is why the wires melted or a fire started, too much current allowed through the wire.

The Right Stuff:
First, only buy fuses that are manufactured in England or Germany (Bosch), and only buy them from suppliers who buy them from England or Germany. This is the only way you be 99% sure that you have the proper fuse for your car. Do NOT use UL/CSA AGC/MDL style fuses in your car EVEN IF you know how to properly size them to protect the wire in your LBC. WHY? Because the person you SELL the car to may not know how to properly size the fuses, and may just end up making the AGC error most people make in their cars. This can also happen if you take your car for service and the mechanic errors with the incorrect fuse.

Where to buy the Right Fuses:
For starts, try British Wiring, Inc., 20449 Ithaca, Olympia Fields, Illinois 60461. Phone / Fax (708) 481-9050. These folks buy their fuses from the UK and know that you must use IEC rated fuses for your British wiring. If you source your fuses from other British Parts suppliers in the USA, ASK THEM WHERE THEY GET THEIR FUSES!! Also, you can get them from the UK, James Paddocks is our chosen supplier for Stag parts of all kinds.

Gotta Keep 'em S-e-p-a-r-a-t-e-d:
When you buy your fuses for your LBC, clearly mark them on the container that they are UK style IEC fuses for use in your car. Do your inventory, toss out any AGC style fuses, or those you do not know the source.

I hope this clears up some of the confusion from the last article and helps keep your LBC from being a burned pile of ash on the side of the road.

By: Glenn Merrell
Stag Owner & Enthusiast
Source: http://snic-braaapp.org/