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Electrical wiring fault finding

Photographs and words: RICHARD ROSENTHAL

Since the feature is focused on finding electrical faults within the electrical wiring system of motorcycles and the immediate connections, it’s best to read the more general discussions surrounding it, which can be available in books and through the web.

Wiring Loom: Wiring harness, wire harness, cable harness, electrical cable harness, cable assembly, electrical cable assembly. No matter what it’s called, it’s a bundle of electric cables (or wires) capable of transmitting electrical signals or power.

Does a motorcycle come with two looms?

When the first manufacturers used charging systems for motorcycles, the wiring loom was a single component usually built on a five-electrical cable design. There were variations of this design; however, more complicated helped machines gain rectified charging systems generated by an alternator and additional electrical cables designed for motorcycles that had coil ignition and battery. In all likelihood, the entire concept was one loom. However, a few looms served those with coil ignition, more intricate switch gears, and other components.

However, there’s more than one circuit within these or this the looms. As motorcycles get more advanced (complicated!) with indicators, electronic ignition, fuel injection, sensors for engine management, onboard computers, and more, it is common to have 12 or more circuits providing either electrical power delivery or signal delivery. So, a motorbike has an overall wiring loom, and other wiring looms.

Are electrical cables from automotive suitable for motorcycles?

In the main, all automobile electrical cables work to be used in the vehicle range, insofar as you select one of the correct sizes since all of them have the same issue, that can efficiently deliver relatively low voltage electrical power (6V, 12V or 24V) from one location to the next.

An automotive electrical cable is several strands, generally of the same size, made of copper wire. There is a drop in the power off, which is more for the cable with a thinner diameter (smaller number of thinner strands) than the more robust electrical cable. However, the difference is minimal when it comes to the lengths used for motorcycles.

The way we live is often in a battle. The need to bend the looms of the frame of a motorcycle and then thread it through tiny holes in the headlights, for instance, results in smaller electrical cables being utilized in harnesses for motorcycles than in automobiles. However, as we’ve explained, the cable with a thinner diameter is more powerful. It is likely to get hotter or warmer (as the current of electricity travels through) as opposed to a more robust cable with the same current.

Wire or electrical cable?

To be precise, we must refer to it as the electrical cable for motorcycles or automobiles and no wire, which is a dichotomy to a certain extent because we refer to the whole loom as an electrical loom, and we connect motorcycles. Please don’t assume that this is my fault! But, it is an undisputed fact that automobile electrical cables are made up of an outer sheath that contains (commonly) at least nine copper wire strands and copper wires, but the sheathed strand is considered a cable, not wire. However, many people, including myself, wrongly refer to the sheathed structures as wires.

Automotive electrical cable grading (sizing).

The grade is described as a two-part figure operated by an Oblique. For instance, in terms of imperial measurements, the cable graded 14/0.010 comprises 14 wires, each 0.010in diameter. The equivalent electrical cable measured in metric terms is 14/0.25, which is 14 strands made of copper wire, each with 0.25mm diameter.

Can electrical cables from commercial and domestic use be used to power motorcycles (or other vehicles of the automotive)? No. We’ve all been able to tangle a wiring loom using cables from the household electrical supply; however, we need to swap the cable to a suitable material once we arrive at the destination. A lot of the household cables are not only more hefty, making it heavier, but it also has several strands of steel-coloured wire (type of wire differs and could comprise big diameter single air, small multiple copper wire, which we’ll leave out here!) with a higher voltage drop than our electrical cable. The drop shouldn’t be an issue, even when longer lengths are used, with household 240V and 3-phase systems for industrial use. However, on motorcycles, we have only 6V, 12V or 24V available to explore drop in volts is significant.

Bunching electrical cables are believed to create a slightly higher voltage drop than when they were separated. The reason for this isn’t apparent to me. However, I’m sure that people will answer; however, please don’t make it complicated! But the fact that cable bundles inside a loom can make it harder for electrical wires to distribute heat than an electrical cable could cause some voltage fluctuations. Additionally, it means that a single cable can carry more current without heating excessively, instead of the identical cable located in the middle of the weaving loom.

How long does a loom last? It is possible those looms made up of cables that are plastic-sheathed inside a loom sheath wrapped with harness tape are likely to last for a lifetime (ours) or even longer… But wear and tear and abuse can wreak havoc on the looms, and motorcycles typically begin the destruction at the point where the wiring loom lies near the head of the wheel. Every time the steering wheel is moved, the sheath gets damaged, slowly the outer sheath becomes damaged, and then the plastic sheath to individual cables wears away, leaving the inner cores and leaks to earth each time exposed wires touch the chassis. A different reason for loom failures is corrosion in the cables, which can cause the deterioration of connections. Sometimes, this can be fixed.

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