Something that catches my eye from time to time is the incorrect use of the electrical term "short".

I am definitely not an electrical engineer, in fact I would call myself a complete idiot when it comes to much more than wiring up a shop or tracing a car problem, but I do understand a few of the terms.

Understanding and using those terms correctly can greatly aid someone as they try to find the cause of a problem in their car and in helping someone else offer suggestions.

Speaking simply a "short" describes a situation in which an electric supply is offered a diversion to ground before it reaches the intended consumer. Say your right head light doesn't work and you see smoke venting from under the hood. You raise the hood and find that the blue and white wire has been pinched and the metal conductor has been mashed against the fender. You will also note that the blue and white wire is mostly no longer there because the insulation has melted and the conductor has been turned into fried copper.

That is a "short".

On the other hand an "open" is where your headlight doesn't work and you raise the hood only to find that the blue and white wire has become disconnected at one of the gang plugs in the forward wiring harness. The circuit is then considered "open" because the electrons do not have a full circle (circuit) in which to travel from the battery through the switch, through the lamp filament and on to ground, which is of course the other end of the battery ground strap.

I suppose that the easiest way to visualize the differences is to remember that a "short" is usually a situation in which you see smoke, smell something burning or feel excessive heat.

In a way you can also consider a short to sometimes precede an open, simply because if left alone the short will burn up the wiring at some point to the extent that the wire falls away and is no longer in continuity.

Remember that an "open" in itself will not produce smoke, heat or flame. It is simply an interruption in the circuit that can take the form of a disconnected wire or an incomplete connection that looks good but is not electrically capable of passing the electrons.

Jack

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I am in the northwestern North Carolina mountains, right up against the Blue Ridge Parkway. Lawn chairs are in the shop and always time to talk. Drop in any time.

You con't know how relieved I am Jack. I thought your were going to say my shorts were open.

Steve

Oh Jack. As soon as I saw your heading my mind travelled back to a summers day in 1960. In Aussie land those very abreviated legged pants are called "shorts". I was down from the country visiting the metropolis in my Austin Healey 100. It was in the days before lung cancer police and I was smoking my favourite "makings" or self constructed cigarette. The top was down and I pulled up at a red light along side a bus with three or four teenage girls looking out the window at me. I fancied my self a James Dean look alike in those days and acted accordingly taking a long drag on my cigarette, as I took the thing from my mouth the paper stuck to my lip and my fingers travelled up the cylinder dislodging the red hot tip. Yes it fell into the open leg of my shorts invoking a very unJames Dean response. I can still hear those peals of girlish laughter as I tried desperately to stop the smell of burning body parts as the bus drove away on the green light and my face turned as red as could be. I gave up cigarettes.

At which point it is now called a "shopen".

..or a fuse. A good fuse is a short. Reminds me of a story (not sure if its real or not) where a "tech" was complaining that all the fuses were bad because the were "shorted out".

A short doesn't have to be a dead short to ground, it can also be an unintended current path, like say the horn wire shorting to the headlight wiring and the lights come on when you push the horn button.

In such a case that the horn activated as well AND the headlights powered on, that would be called a 'cross'. Yet another one of the electrical god's attempt at humor.

Shorts, opens, crosses, how would the world exist without such demons.

Jim B.

OMG Alex, and that guy makes the big bucks.

A good example of a short is a 49 Mercury two door, that has been shaved, sectioned, using lowering blocks, heated coils, reversed wheels with beauty rings, and Frenched lights and radio antenna.

Oh, yea, shorts always have windshield visors and fuzzy dice too.

A three speed gear box with Zephyr gears and all of the seams filled with lead instead of Bondo make it a "Lead Sled Short".

Jack

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I am in the northwestern North Carolina mountains, right up against the Blue Ridge Parkway. Lawn chairs are in the shop and always time to talk. Drop in any time.

A fuse is a device that turns a short into an open at a location that is easy to find - hopefully before it does the damage Jack described.

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Jim

"If you want me to agree with you then we would both be wrong"

'66 MGB widened 11" with LT1 Chevy and 6 speed, C4 Corvette suspension
Pictures here Part 1 http://forum.britishv8.org/read.php?13,7581
Continued in Part 2 http://forum.britishv8.org/read.php?13,22422
Continued in Part 3 http://forum.britishv8.org/read.php?13,33108

Like the fuse that kept blowing in the 75 that is sitting in the shop.

Come to find out the idiot that converted the car to a Weber, just whacked the induction heater line and stuffed it down behind the back of the alternator.

On certain occasions, like kissing an expansion joint, the end of the wire, covered in oil and grease I might add, would contact the block for a moment, thus creating a short and converting that into an open.

The real open will occur when the customer has to open his wallet and pay me for fixing yet another six dollar hair cut.

Jack

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-------------I like to think that I don't service automobiles so much as I provide entertainment, fulfill dreams and revive wonderful memories --------------

I am in the northwestern North Carolina mountains, right up against the Blue Ridge Parkway. Lawn chairs are in the shop and always time to talk. Drop in any time.

Are any of these linked to the "fused link" wire that burns into because of a Poor Ground? This not not isolated to autos alone, since I've seen breakers and receptacles (Plugs)in houses burned also. Note above "Fused Link" is not a wire of smaller gauge as normally used in std. harnesses.

I am an electrical Engineer so I can usually tell what people mean when they mis-use electrical terms.
I have more trouble trying to translate the Americanisms. What the hell is a reversed wheel & a Frenched Light?

Ig

"Standard rims have a shallow side and a deeper side. The deeper side is the side that goes over the drums or calipers. When the rim is reversed the deep side faces out."

ussually just meeans big offset out

Thank you Keith.
- & a Frenched Light?

A French Lite could be a cigarette, I suppose.

A light that has what would be the trim ring, moulded into the fender for a sleek streamlined look.

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79 RB Lowered, De-smogged, HS4s by Dave Braun & "Schlemmerized" dizzy. Pretty much stock other than that.

Next up: impedance and impotence.