UK automobile electrical systems: why so bad?

Whenever anyone discusses cars from the UK, usually that conversation is accompanied by a Lucas Electrics joke. “Lucas is the patent holder for the short circuit.” “Lucas - inventor of the first intermittent wiper.” “Lucas - inventor of the self-dimming headlamp.”

I’m wondering … why were electrical systems in British cars so bad? What was it about the engineering that caused the electrical system to be so quirky? If Lucas Electrics had such a bad reputation, why did British auto manufacturers depend on them for the design of automotive electrical systems?

Lucas - Prince of Darkness. Only organization I’ve ever run across that could disable a car with a bad tail-lamp.

I don’t have any cites on hand, but I do know that a lot of Lucas’ work caused problems because they were almost too innovative.

Say you have something such as the radio or electronic ignition, which you need to run at less than full-strength 12 volts from the battery so it doesn’t burn up. To do this, simply put a resistor in the circuit, so the power gets reduced and limited by Ohm’s Law doing what it always does. Where do you find a resistor in a car? Well, light bulbs all have resistance, so they can be used as resistors.

So, you wire up the ignition in series with a tail-lamp. The module gets the reduced power it needs and is such a low-power thing that it doesn’t really affect the light. Wonderful! By using something that’s already in the car, you don’t need to buy and install a special reistor for it.

Well… sooner or later, the tail-lamp will burn out. When this happens, the circuit is open and the ignition system no longer gets power. Car is dead.

Nutty, but I’ve seen it. (On a schematic, as opposed to being stranded somewhere.

This goes back a long ways. I recall seeing a cartoon in Punch (the old Punch, RIP) many moons ago about why the British space program never succeeded. The cartoon showed a rocket emblazoned with a Union Jack, and white-coated figures scurrying around trying to figure out why it wouldn’t lift off—and all the while the answer was in plain sight on the side of the rocket: “Ignition by Lucas.”

Okay, the description is kinda lame; but the cartoon was hilarious. Trust me. . . .

Why do the British drink room-temperature beer?

Because their refrigerators are made by Lucas.

Lucas was there before God. Lucas invented darkness.

? I am a birt and I have no clue what/who ‘Lucas’ is.

birt or brit??:smiley:

I’m not a Brit, but all this stuff is sorta familiar to me. Back in the 1950’s and 60’s (and certainly before,) Lucas Electric made all the switches, headlights, ignition, etc.,etc. for all British cars. In those days, they were famously unreliable. Nowadays, they are famous for finally getting it right.

If Lucas made asault rifles, wars wouldn’t start either.

On some late model MGB’s there was a rack of relays mounted under the hood. For ease of installation the relays were mounted with the electrical connectors pointing up. Now did I mention that these relays were metal cans that were not weather sealed? First rainstorm and all the relays filled up with water and shorted out.

Lucas tried to repeal Ohm’s law, but they ran into too much resistance.

I’m British, I have heard of Lucas (they even had a plant near where I grew up), but I’ve never heard any of those jokes or any of that stuff about Lucas being unreliable before. Maybe it’s an age thing, maybe they used to be unreliable & got better? (but I have no idea how old the other posters are :D).

I don’t know if this has anything to do with Lucas or not, but my dad always talks about his older cars (older being 60-70’s) which he was able to apply pressure to the break and turn the igniton key just the right amount (with the car off) and it would turn the radio on.
(But then again, he also screwed up the wiring in a stereo once and now with the ignition off, you can power the radio by turning on the headlights. While it’s kind of a nice feature, he also managed to short out the dashlights, and now if you want to check your speed at night you have to flip the dome light on.)

So how much market share does/did Lucas have, and why were they able to maintain it if their products were so poorly designed? (I think that’s what the OP is asking, and I’m curious too.)

Most of those awful old British cars - MGs, Triumphs, Minis etc. - were made by the same state-owned company, British Leyland, which might explain why they all used Lucas parts.

Ditto - wonder if we’re from the same place … begins with S?

Julie :slight_smile:

They weren’t awful. For their time, they were wonderful. The MGB is one of the most successful sports cars ever, with over half a million made.

And MG and Triumph were seperate companies. But British car compamies seem to have traded ownership more often than properties in a game of Monopoly. Eventually they did end up under British Leyland, but they started out individually.

As a former British sports car owner, I can tell you that Lucas electricalssystems had a lot of problems. This was also due to the British prediliction for cotton-insulated wiring-long after american, german, and japanese producers had converted to plastic insulation, the brits continued to use cotton-fabric insulated wires. thjis lead to many short circuits on wet days. Another thing…the Lucas distributors were extremely complicated in design-so that changing the breaker points was an all-day exercise. I could never understand why they had to be so damn complicated…I guess they liked it!

Back to the OP’s question: a few more notes about Lucas electrical systems and why they were not so hot:

Many of the early Lucas electrical systems used a generator rather than an alternator to generate electrical power. Generators contain metal brushes that rub against the rotating coil inside the generator, leading to obvious wear problems. As the brushes wore out, you would lose charging capacity, and hence electical power. Alternators, on the other hand,contain no rubbing parts.

Lucas systems also used a positive ground as opposed to the more common negative ground. Not sure if this in and of itself cause reliability problems, but it meant that you could basically only use Lucas parts for replacement and repair.

Lucas was also fond of using different metals in their contacts. The disparate metals in contact with each other led to corrosion problems in the contacts. Although this was not uncommon in the past, in combination with the less than stellar weatherproofing common in British cars of the era, it led to many fouled electrical contacts as ** Rick** mentioned.


Perfectly sunny day. Low 80s. Perfect for a ride with the top down.

My brother, Brad: “Hmmm, let’s not. It looks like rain.”

Me: “What? The weather’s perfect.”

Brad: “Nope. We’re going to get rain. The MG won’t start.”

You can bet it rained. Every damn time.

I used to own, or maybe I was owned by, a 1966 Sunbeam Tiger. This car had a Ford V8 engine, but other than that it was a Sunbeam Alpine. The charging system worked fine, Ford alternator, but the rest of the system was pretty poor. Lights would brighten and dim for no known reason, relays would fail on a regular basis.

A friend had a 1965 Alpine and the alternator failed. In 1968, a new Lucas alternator cost $195 US! We disassembled the alternator, soldered the broken wire, and rewound and assembled it. Worked for two years until he sold the car.