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What is Voltage Drop and How to Prevent It?

What is Voltage Drop and How to Prevent It?

Posted by Chris Johnson on Dec 16th 2015

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The Garden Hose Analogy - Understanding Voltage Drop

Have you ever heard of the electricity/water analogy?

If wire is a water pipe and electricity is the water, voltage is the pressure of the water.

I'm a writer, not an engineer. So making sense of the technical aspects of light and energy is sometimes challenging. I need graphics and analogies to wrap my brain around them.

As I was working on some content about the very engaging topic of (dun-dun-dun) voltage drop, and specifically, how to prevent it in low voltage lighting systems, I came across the water/electricity analogy. It made sense to me and allowed me to put voltage drop into a context that I could better understand and I thought it was worth sharing.

For my purposes, I have changed the analogy up a bit. Instead of a pipe, my electrical wire is represented by a rubber garden hose. Electricity is the water flowing through the hose and voltage is the pressure of the water in the hose.

If you turn the valve on full blast, you have a gushing spray of full water pressure at the end of the hose. Now, let's say as you drag the hose through the yard it catches on rocks and sticks and rips 5 tears into the hose (this is a cheap dollar-store water hose, by the way).

At each new rip in the hose, the water squirts out, releasing water pressure a little bit more each time. By the end of the hose, the water pressure is much less than at the beginning.

Now, let's apply the garden hose analogy to electricity.

Instead of a water hose, imagine a run of 5 path lights. The first path light (a "rip" in the hose) drains a little bit of voltage but still supplies more than enough to light the lamp fully. The next one drains it a little more, and by the 5th path light in the series, your voltage has "leaked" enough that the last bulb is dimmer than the others. This is voltage drop.

It may not be an exact science, but for this visual learner, it works.

How to Prevent Voltage Drop

Okay, now that we know what it is, how do we reduce or prevent it in your electronic transformer so that the last bulb in your run of lights is just as bright as the first one? Here are four simple words to help: Short, Thick, Twist, Split.

  1. Shorten the distance.
  2. Use thick secondary wires.
  3. Twist the secondary wires.
  4. Split the output.

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