Is Dirty Electricity For Reals?

Power quality is actually more of an issue than 20-30 years ago. Many modern loads present new power quality problems (harmonic distortion, high frequency noise, etc.) and have their own unique sensitivities. For example modern variable frequency motor drives can be very sensitive to utility 3 phase voltage unbalance while increasing transformer heating due to harmonic currents. Another example, wide voltage input SMPSs common for modern electronics may not have much ride-thru ability to handle voltage sags.

If you want to get a utility engineer really fired up, ask them how easy it is to deal with “distributed generation”, where their customers are adding their own solar and wind power to the grid. Economic and environmental pros and cons aside, this significantly complicates the power quality situation.

And here I thought this was going to be a thread about hot Amp-on-Amp action, to include obligatory, over-scripted, under-acted pickup lines like, “What’s your gauge, baby?” and “Show me your bus bar big daddy”.

No such luck.

Tripler
The NEC gets me all hot and bothered. . . awww yeah.

Two Wires, One Wire Nut

In certain circles, I’m known as Square D.

Tripler
I can dig some 3-phase action.

Don’t overdo it. You can get soares from all that bonding.

This is done so well, I figured my clamp ammeter wasn’t working. No, it works, but is designed to be clamped around one wire only, and it gauges the amps flowing through the wire by the induced current from the field around the wire. But with the wires bound closely together, as they typically are, these fields are canceled so well I thought the ammeter was broken. Silly me.

Yeah it’s the one catch with the excellent little clamp metres you can get now. Being able to measure current without having to cut into the circuit is brilliant but when you can’t find anywhere to hook around one side of the circuit it’s irritating.

During the height of the EMF craze in the 70-80s I worked for an electric utility. We had tons of customers calling us and complaining that they thought our distribution lines were bombarding them with EMFs. We had a technician who would travel to their homes while carrying an EMF meter. He would stand under the distribution line and hold the EMF meter up to show the customer the reading. Then he would go into their homes and hold the meter close to their running refrigerator. He would show them that their refrigerator was giving them at least10 times the exposure as our power lines.

My uncle’s memoir has a story about rural electrification in the 40s. Households would engage an electrician first to run the wires, which sometimes happened before the power company got that far down the road. Quote:

[When the electrician got to a pre-wired house to connect the lines] all the drop cords had corncobs screwed up in the receptacles. He went about taking the cobs out and replacing them with light bulbs, pulled the chain and the lights came on. He asked “why were the corn cobs screwed into every receptacle?” “Well, I was afraid the power company would come along before you got here, and turn my electricity on, and it would run all over the house.”

So ventilation is important. Got it! :grin:

Heh… yeah, not unlike the issues with indoor air quality, but also not quite like it (as Inigo cleverly points out). Though it does create a bit of curiosity of what is the difference between “natural background” EMF or “domestic EMF” vs, for instance, the EMF in the middle of Times Square or at one of Big Tech’s announcement events.

You need a breakout (line splitter). You can easily make one with a plug, socket and short wires.

https://www.amazon.com/Extech-480172-AC-Line-Splitter/dp/B0000YHN9W

Back in college, I participated in a debate on nuclear power (I was/am pro). It was an eye-opener to some of the con side that, because of where the university was located (basically on top of a huge sheet of granite) that our background radiation reading was higher than what you find next to an operating nuclear plant.

Good post.

Question.

The low frequency hum caused by corona discharge that is sometimes there may could cause stress and poor sleep. I know I found it annoying when I camped near some power lines, and it was hard to sleep. Has that been looked into?

I made myself one of those but it’s actually rare that I want to measure the current on the main power cord of an appliance so it doesn’t get much use.

For loads under 15 amps the Kill A Watt monitor is a pretty handy device. The ability to measure energy use over a long period of time is the main use of such a device, but I have used it before to measure the power draw of small appliances like space heaters to see what they pull at low, medium, and high settings.

Yeah I have one of those. Which is another reason I don’t tend to need to use a clamp meter for measuring appliance current draw.

Ohm I.

Plus IIRC most long distance power high current lines nowadays are DC which give off a lot less of a field than AC. And electromagnetic field from a wire will fall off as inverse square of distance, so unless you live near the feeder lines for the whole city, you are probably getting more electromagnetic field strength from your toaster.