Learn About Electricity And Controls

 

January 1, 2003

 

 

My father was an electrician, my grandfather was an electrician - but I was a girl. That means I had to learn electricity like most folks in our business - as an adult, on my own and with lots of unanswered questions.

 

I mention my family of electricians so that you don't misunderstand me. I like electricians, but I think we in the heating business need to do our own wiring of controls.

 

Let me tell you a little more about myself. I'm a degreed technical trainer and writer. I've been working in the controls business for over 20 years. I've published three books about electricity, controls and troubleshooting especially for the heating industry. I am positively enthusiastic that plumbers and electricity can mix!

 

Unfortunately, our industry has let electricians and engineers have custody of electricity. For a number of reasons, we've decided that electricity and controls are too difficult for us.

 

  • None of the following reasons, however, have to do with our ability. Let's take a look:
  • Electricity books are hard.
  • Electricity classes don't relate to the work we do.
  • Electricity classes have us do a lot of math, and that doesn't relate to the work we do either.
  • We're water folks, and everyone knows electricity and water don't mix.
  • The "water analogy" (that is, electricity's just like water, stupid) doesn't really make sense.

 

As a result, we've agreed to let someone else (perhaps someone "smarter?") do the controls work. That's a mistake. Here are some reasons we shouldn't let someone else do the controls work:

  • Electricians often don't know how to wire controls circuits either.
  • Electricians don't understand controls circuits, and at the same time think themselves above it.

 

If we're responsible for the job, we should do the job.

 

Why pay someone else?

 

The fact that an electrician can't get it to work doesn't mean it's a difficult job. It just means the electrician doesn't know how to do it.

A couple of years ago, I polled some plumbers who do hydronic heating and asked for the name of an electrician who does a pretty good job on controls. I called the electrician and asked to "buy" an hour of his time to answer any questions I asked. He was a little put off at first - suspicious about what I was really up to. But he got over it pretty fast when I offered to pay him his hourly rate to sit in his office and talk. What came out of the question and answer session is this:

  • Electricians have no more training about controls than plumbers do (yep, scary thought).
  • Electrician training is about pulling wires and applying code.
  • Electricians don't think in terms of circuits - they pull wire from this point to that.
  • Electricians don't think about electricity - they think about wire and code.
  • Electricians know that if the wiring doesn't work, the problem is a bad control.
  • Electricians know they know more about everything than the rest of us do.
  • Here's the bottom line: Electricians have no more training about controls and controls wiring than plumbers do!

 

 

Confused & Confusing

What this means is that to be in the hydronic heating business, you need to learn controls and controls wiring. But how to learn? Electricity books are often difficult - needlessly so.

 

I've given lots of thought to that problem, and I'm sure this is what's going on. There's a "tradition" of how an electricity book should be laid out. It starts with electron theory. You don't need to even think about electrons when you use an electric appliance or tool. So why would you need to think about them to wire a circuit? Besides, they're invisible. Thinking about what the electrons are doing is about as useful as needing to think about air molecules in order to breathe.

 

Then electricity books move on to Ohm's Law. That means formulas, math and fractions. That's when most of us check out. It's too bad that a lot of us don't think, "Hey, I think this might be pretty much useless information."

 

It gets worse. If we get through Ohm's Law by the skin of our teeth, low and behold, Kirchoff's Law is next. More formulas, more math and more fractions. But this is much worse because Kirchoff's law is about putting loads in series.

 

Loads in series? As it turns out, one thing we most want to avoid in wiring controls circuits is putting loads in series. So we slog through pages of math and hours of boring classes to learn how to do math about something we should avoid doing on the job. This is totally nuts!

 

Maybe, just maybe, we get past Kirchoff. Then, we get to something real - motors. While it's nice to know what's going on inside a motor, again, it's not what we really need to know. Being able to describe what goes on inside a motor doesn't help wire one in a control circuit.

 

Above all this confusion rests the "water analogy." Its says electricity is just like water. Water flows; electricity flows. Water has a current; electricity has a current. Water can be pumped; electricity, in a sense, can be pumped.

 

I had a major problem with this. While many electricity books smoothly move on to open circuits and closed circuits, I knew they were lying to me about something. With water, the water is "on" or "off" depending on whether the valve is open or closed. On = open and off = closed. Everyone just knows how this works. Whatever substance we're talking about, stuff flows when the valve is open.

With little in the way of transition, however, many texts move on to electricity. Suddenly, "opened" means the light is off, and "closed" means the light is on. More has changed here than that the stuff is now electricity. And they're telling me this is just like water? It's not just like water - it's the exact opposite.

 

Amazingly, every electricity guy I talked to professed that the water analogy is true, shaking their heads a bit that an otherwise smart person couldn't understand this simple concept.

 

But I finally got it. Know what you know, they say. And I'm in a position now to know that the water analogy is valid only up to a point. That point is where the flow is controlled. Water is controlled by valves. Electricity is controlled by switches. They don't work the same.

A switch works like a drawbridge, not like a valve. Electricity runs on wires, not through wires (even though we have the very misleading terminology of electricity going through wires). So when the switch (drawbridge) is open, there is no path, and the electricity cannot flow. When the switch is closed, stuff flows.

 

Once we get this straight, it's easy to understand a lot of other "mysterious" things about electricity. In upcoming columns I'll talk about why we put switches, but rarely loads, in series. I'll talk about the fact that a thermostat is just a switch. I'll talk about polarity, and why there is polarity on the primary side of a transformer, but not on the secondary. I'll talk about what voltage drop is, and how to use it to troubleshoot.

 

The theme will always be the same - electricity and controls can be very simple. In our industry, they're like water and air - they should belong to all of us. Claim them as yours.

 

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