Very early in my career I learned the trick of touching things very lightly before grabbing them firmly. That way there is only a tingle when touching something that is not off. In many places I also would use a shorting probe to ground the circuits that I needed to touch, which has saved me from shocks a few times. The third trick is using one of those neon circuit testers, but holding the bulb between my fingers. That will show higher voltage AC and demonstrate the need for additional checking prior to touching.
The high voltage in transmitters is a totally different situation though, and must be dealt fith far more carefully than even the 480 volt AC circuits. After you are certain that everything is off and discharged, then use the meter and extended probe to check again!
MY guess about the tale is that there was a small bit of "attitude problem" that provoked the tech to not mention that the switch was failed. Most techs are far more decent than that.
You're right Gsmith120. He asked the technician to turn off the switch. So there is no excuse when the technician later says the switch is broken. It's really unfathomable.
I too have been bit by my wedding ring - once. Learned to put it in my pocket when working on equipment, live or not. Capacitors can sometimes stay charged for a bit with the power off.
My other pet peeve is the way tie wraps are sometimes carelessly installed. When one is working on live equipment as a necessary part of troubleshooting, a prick on the back of your hand can cause one to instinctively back out in a hurry. If the prick is from a poorly cut off tie wrap, a nasty gash can appear on the back of your hand.
Always a good idea to groung everything. An isolated motor with a spinning pully and a rubber belt makes a great Van de Graaff generator. The kind in science museums that through sparks several feet.
In my earlier years, I was a project engineer for a large radio communications equipment manufacturer. In that capacity, I designed several different r.f. amplifiers with output powers ranging from 400 watts to 10Kwatts. To achieve those outputs, required PLATE voltages from 500V DC to 5KV DC. One learns in one heck of a hurry that you not only place your weaker hand & arm behind your back, BUT you get one of your technicians to physically tie it there w/ rope designed to hold the U.S.S Forrestal @ the pier. There are NO 2nd chances w/ this level of DC power, considering that it is NOT only the voltage, but also the current. Typical plate current for a 1Kwatt transmitter is in the order of amperes. For a 10Kwatt transmitter, it's in the order of tens of amperes!
Yes sir, kf2qd has hit the nail on the head, any professional electrician will tell you this is exactly the right proceedure. And if you are not a professional electrician, get one! :)
I'm telling this two-part story as it may save some reader from a nasty shock or worse. I'm a Mechanical Engineer with a very low level of electrical savvy; however, out of necessity, I have done some basic car and home wiring. When it comes to transistors, frequency generators and other such electrical components, I'm totally mystefied. 1. I have a small metal cutting lathe at home which I upgraded the 1/2 H.P. electric motor to a full 1 H.P. motor. Somehow while wiring up the new motor I realized that the motor was mounted on a pivot plate bolted to the wooden bench while the power switch was mounted to the metal lathe. This means that the motor was not grounded, and if it ever shorted to its frame and I reached over and touched the metal tensioning lever with one hand and kept my other hand on the lathe, I could receive a jolt of 110 AC volts through my chest. To rectify this, I simply ran a green grounding wire from the switchbox grounding screw through the flexible conduit to the motor frame grounding screw. 2. One month later, I read in a trade magazine that an air conditioning service man was replacing a fan motor on an industiral size unit. The existing motor was a replacement for the original put in by another serviceman and was not properly grounded. When the man reached in through the access port and touched the motor, his upper body was in contact with the metal housing and he received a fatal shock.
After taking a few 110 volt shocks, I invested in a circuit tester with lights and an audible alarm to check for a live circuit. It is worth its weight in gold.
By experimenting with the photovoltaic reaction in solar cells, researchers at MIT have made a breakthrough in energy efficiency that significantly pushes the boundaries of current commercial cells on the market.
In a world that's going green, industrial operations have a problem: Their processes involve materials that are potentially toxic, flammable, corrosive, or reactive. If improperly managed, this can precipitate dangerous health and environmental consequences.
With LEDs dropping in price virtually every year, automakers have begun employing them, not only on luxury vehicles, but on entry-level models, as well.
From Dell / Intel® New Paradigms in Design Work Scott Hamilton, vertical market strategist for Dell Precision workstations, 5/2/2013 5
Early in my career, I worked as a draftsman and remember the days of drawing on vellum with numbered pencils and Mylar with plastic lead. This was a fun experience in the sense that I ...
I've been using workstations for more than 10 years and love finding ways to get more performance from my system. With demanding professional applications that require more power each ...
A lasting memory from my first job as an engineer in an auto assembly plant is standing on hard concrete at six in the morning, vending-machine coffee clutched in hand, listening to ...
A quick look into the merger of two powerhouse 3D printing OEMs and the new leader in rapid prototyping solutions, Stratasys. The industrial revolution is now led by 3D printing and engineers are given the opportunity to fully maximize their design capabilities, reduce their time-to-market and functionally test prototypes cheaper, faster and easier. Bruce Bradshaw, Director of Marketing in North America, will explore the large product offering and variety of materials that will help CAD designers articulate their product design with actual, physical prototypes. This broadcast will dive deep into technical information including application specific stories from real world customers and their experiences with 3D printing. 3D Printing is
To save this item to your list of favorite Design News content so you can find it later in your Profile page, click the "Save It" button next to the item.
If you found this interesting or useful, please use the links to the services below to share it with other readers. You will need a free account with each service to share an item via that service.
Tweet This
3 
