If a chunk of concrete or similar material has become lodged in empty conduit, chuck up an appropriate length of fishtape in a drill and use it to break through the offending item. Then use your shopvac to remove the debris. As a corollary, save short lengths of broken fishtape as they are handy in many situations.
When temporarily taping materials, leave an inch of tape. Make a tail by spinning it between your fingers, so that later you won't have to dig to find the end.
A fishtape is spring steel, halfway between mild steel and hardened steel. If you try to bend it too sharply, it will usually break. If the end breaks off, you can make a new hooked end by annealing it with a propane torch. Heat it red hot and allow it to cool slowly. This process softens the metal so that it can be formed with needlenose pliers.
Regularly inspect the handles of insulated tools for deterioration that can be hazardous. An almost invisible crack can hold moisture and conducting grease. Heat shrink tubing installed on the handles of pliers will make them like new but insulated handles should never be trusted for high voltage or when you are on a wet surface or otherwise grounded.
A pencil eraser will remove high resistance oxide coatings on electrical contacts in a motor controller, TV remote or anything in between. Rub the eraser vigorously on clean paper until the shelf life glaze is gone, then polish the contacts -- will not remove severe pitting or burning but it works for early stages of oxidation and is great preventive maintenance.
When running multiple parallel conduits across a ceiling or wall, make a plywood template based on originating panel knockouts to aid in maintaining uniform spacing. Secure conduits to struts without fully tightening strut clamps at first, then check alignment at each strut and tighten. Use the same template for drilling holes through an existing wall.
Using a tablesaw, make a V-block from 24" 2X2 and mount on a fairly short-legged sawhorse. This greatly aids in cutting conduit in the field where a bench vise is not available.
The National Electrical Code requires emergency lights to be regularly inspected, and a record kept. The time interval is not specified. In a large facility maintenance electricians are entrusted with this important job. Place the results in an Excel file and compare results to see which units are eating batteries. These will need new circuit boards.
When upgrading a service, the old branch circuit wiring must be removed from the entrance panel so that a new breaker box can be installed. Don't pull the stripped cables out through the connectors -- that is sure to nick the conductors causing shorts later. Instead, remove locknuts from the inside of the box and leave the connectors in place on the cable jackets. Re-attach in the new box. That way is easier and less hazardous.
If a telephone has no dialtone and appears "dead" lots of times its just the receiver cord, linecord or receiver in that order of probability.
You can make saddle, offset or simple bends in PVC conduit (RNC) by heating it uniformly and forming the bend by eye. Do not use a propane torch -- you will burn the outside before the inside is soft enough to bend. An electric blanket PVC conduit bender works very well but is expensive and prone to burn out. Various tools that use your vehicle's exhaust are on the market. Use your ingenuity and see what you can invent!
If a small electric motor like in a fan won't start when energized, see if it turns hard by hand. If you give it a spin, it should coast awhile, not stop right away. If this is the case, oil the front and rear bearings. Use penetrating oil at first, then follow up with a heavier machine oil to provide lasting lubrication.
The National Electrical Code says a run of conduit has to be put in as a complete system, terminated at both ends, before installing conductors. You can put in a pull rope as you hook up the conduit lengths, but not conductors. Sometimes the easiest way is to use a shopvac to pull a piston (so-called "mouse"). This is a foam rubber cylinder sized to fit the pipe, with string attached. If a piston is not available, make your own by carving it out of foam or similar material.
To mount a fluorescent strip fixture on a sheetrocked ceiling, it is necessary to screw through the drywall into framing. Don't worry if the holes don't coincide. Use your cordless to screw right through the sheetmetal without regard to the predrilled holes.
Wirenuts in questionable environments should be installed with the openings down so that any moisture will drain.
Before commencing work on a light fixture directly over a sink, close the drain. If a screw or small part is dropped, it won't be lost.
If an incandescent light fixture won't work with a good bulb in place and power coming in, it is possible that the center spring terminal in the light socket has lost its tension. With power off, grab the "piton" with needlenose pliers and give it a good pull. This works often on old fixtures.
In a large facility where it is frequently necessary to test incandescent or self-ballasted fluorescent bulbs, you can make a quick tester mounted on the wall above your bench in the maintenance shop. Using a hacksaw, split the screwshell of a porcelain base fixture. Then, you can stick in the bulb to be tested without screwing it in.
For a superior finish appearance, tighten screws in wallplates so that the slots are perfectly vertical.
In an excavation or other damp place, use cordless power tools only. If this is not possible, make sure that the power supply is GFCI protected.
Use a digital camera to depict complex machinery prior to disassembly to aid in getting it back together correctly.
If you have a complex piece of machinery that requires frequent servicing, run Cat 5 cable through grommets in the sheet metal and fasten to key test points. The color-coded ends can be used to perform voltmeter and oscilloscope readings outside while the machine is running.
The first step in servicing many types of nonfunctioning tools and appliances can be to fasten an ohmmeter to the plug. Stick the probes through the holes in the prongs and hold them in place with a wrap of electrical tape. Put the ohmmeter in honk mode and work the power switch or wiggle the cord. For a motorized tool such as a drill, you need to have continuity through the cord, switch and associated wiring, through the brushes all the way to the armature.
When putting in a new service, put a very small dab of corrosion inhibitor on each connector of the meter socket. Then the utility workers can put the meter in more easily and if it ever has to come out, that will be easier also.
Telephone servicing is much easier with three simple tools: a test set, tone generator and wand. Some technicians use an ohmmeter instead but the foregoing reveal sound quality issues as well.
For most of us, it is not possible to memorize the provisions of the National Electric Code. Instead, learn to access answers to questions on an open book basis. It is suggested that you spend a lot of time reading and understanding the Table of Contents and the Index so that you know which of these to consult in various cases, and what the keywords may be. You should also know the contents of particularly important articles such as 240, 250 and 430.
In the course of upgrading a service or reworking existing wiring, it is often found that the panel directory is in poor shape due to inaccuracies, bad calligraphy or tattered condition. You can print a new one on your computer using heavy paper cut to fit. Use the Excel program to make rows and columns. If you don't use Excel, you can use Microsoft Word, but it is more difficult to line up the spaces for double-pole breakers. After doing one of these jobs, save the directory in your computer. Then next time you can just enter new data. Be sure to include your logo with phone number.
To bend and shape large (1/0 and up) insulated conductors in order to make meter socket and panel terminations, use the hole, with its well-rounded edges, at the end of a large adjustable wrench handle.
Large electrolytic capacitors have a limited shelf life. In the case of a good one, an ohmmeter set on a high range will "count" first one way, then the other, as the leads are reversed and the internal battery alternately charges and discharges the capacitor. Sometimes a bad electrolytic capacitor can be brought back to life by applying a steady DC voltage.
When soldering electrical work, use resin, not acid flux, which is good for water pipes and radiators, but will leave a corrosive residue on printed circuits boards and the like that will eventually compromise the conductivity of even a properly soldered joint.
Short pieces of the jacket of Cat 5 communication cable with conductors removed make good protective sheathes for small conductors such as motor leads that may chafe. These pieces can also be used as sleeves to identify multiple ends that are to be terminated later. A fine point Magic Marker works for labelling the individual tubes.
When finished soldering, retin the soldering iron tip so that it is ready for next time. Tinning the tip prevents corrosion. If the tip is corroded, the oxide coating acts as an insulation and prevents heat transfer so that it is impossible to solder. Disconnect the soldering iron and apply solder as it cools. To clean a corroded tip, heat it up and wipe it on a damp sponge. Apply flux and solder as it cools down.
A stereo amplifier is easy to fix. If the unit is dead, check for a cord, switch or power supply problem. If one channel is out but not the other, take readings at various points and see if there is the same reading in the other channel. Suspect a bad speaker, which can be checked by applying voltage from a drycell. As polarity is reversed, the cone should either pull in or push out.
The code permits ungrounded systems in certain applications. Of course even an ungrounded system has to have a green or bare equipment grounding conductor connected to a ground electrode with the full set of rules.
If an elevator quits, try resetting the control panel and see if there is a fault code on the screen. Consult the maintenance manual to see what the code means and what the common remedies are. A very frequent fault is a bad or loose door sensor, which tells the CPU that a door is not closed, which prevents the motor from running. Most elevators have DC motors, with the rectifier in the control panel. Consult the maintenance manual for voltages, etc.
When wiring a three-phase motor, it is important to balance the phases. The idea is that one leg of the supply will likely have a slightly higher voltage than the others, and one leg of the load may draw a little more current than the others. Hook up the motor with the desired rotation and then take clamp-on ammeter readings. Then roll the connections without reversing any two legs, which would reverse the rotation. Take readings for all three configurations and whichever set of readings is most uniform is the right hookup. After connections are finished in the motor terminal box, the wiring has been stuffed in and the cover is screwed on, go back to an upstream access point such as the three-pole breaker in the panel, and with power off take ohm readings. The resistance in all three phases should be substantially equal, say 3.9 ohms, and there should be no resistance to ground at a high megohm range setting. That means wiring is correct, except that rotation may still be wrong. Often it is safe to try out the motor briefly to check rotation, but beware of some pumps which can be instantly damaged (seal ruined) when run the wrong way.
When installing a submersible well pump of one horsepower or less you can dispense with the pull rope. It is just in the way and the pipe-wire combination is capable of pulling up the pump if that ever has to be done. Some installers leave out the torque arrestor, but that is a bad practice since reverse torque when the motor starts and stops can lead to a chafed wire and ground out one of the conductors.
When repairing a VCR or similar equipment and you can't find the problem, try going over all the solder joints with a hot soldering iron. With time, one or more of them may have oxidized at a cold joint making a high resistance connection. Another possible remedy is to separate and reconnect all the ribbon connectors, which polishes and restores the contacts.
The last article of the National Electric Code covers Network-Powered Broadband Communications Systems. What "network-powered" means is that in addition to a data signal for telephone, cable TV or interactive services, the line also carries a DC or AC voltage which is used to power any electronic components such as required for amplification along the way. In the early years of telephone technology, each phone contained its own batteries. If you look inside a modern phone, you will see solid state components for amplification, but no power supply or rectifier. A DC voltage is provided by the utility and accompanies the voice signal on a single pair of conductors.
TV cable typically has an AC voltage of about 60 volts, which can be introduced at any point or points along the line. The amplifiers, which may be every 400' along the line, contain transformers and rectifiers which power the solid state amplifiers. The AC is blocked so that it does not reach the TV.
A common reason for a TV cable system going down is loss of AC power at the service, and the repair can be as simple as resetting a breaker. An important troubleshooting technique is to take voltage measurements at the input and output of amplifiers along the line. These amplifiers are in weatherproof gasketed boxes which may be opened to change modules. Also look for problems with the connectors.
A useful item in the electrician's toolbox is the neon testlight. It is good for taking readings to determine presence or absence of voltage when the exact number is known anyway. You can determine whether a conductor is grounded or ungrounded where the system is no greater than house current, by putting one probe on the conductor in question and touching the other with your finger. The neon bulb will glow faintly if you have the hot wire. The resistance of the bulb and series resister, which is inside, is so high that a neglible current flows through your body to ground, no more than if you were to touch a C cell.
For troubleshooting receptacles, use an applaince bulb screwed into a plug-in socket. This is easier than using a meter, where you never know if the test leads are making contact. If the receptacle is within sight of the panel, leave it plugged in while you locate the breaker. If it is not in sight, use a transister radio turned up loud.
If an arcfault breaker is tripping out and you expect the trouble is a partially severed wire inside a wall, replace the arcfault breaker temporarily with a 15-amp standard breaker. Use the antenna of a battery operated transister radio tuned to no station with the volume high. Probe along the wall and listen for static. Start with a light load at the nearest receptacle, and go from there.
Old audio speakers are an excellent source of small powerful permanent magnets. Among others, they have these uses: l. Stroke screwdriver tips several times in the same direction to keep them magnetized. 2. Use them to collect metal shavings when drilling near printed circuit boards. A metal shaving can short out adjecent traces and put a piece of equipment out of order. 3. Attach them to a piece of wire and lower into inaccessible regions to retrieve dropped tools and parts.
A submersible pump of three horsepower or higher should have soldered pump cable splices. Crimp the connectors in the usual way, then apply resin flux and run solder into the crimps.
Sometimes when a large piece of machinery has a noisy bearing, it is difficult to determine which one is the culprit. You can use a long screwdriver as a stethoscope. With your ear against the handle, touch the tip to the outer housing of each bearing to pinpoint the problem.
Electricians frequently deal with wood framing members in both new construction and renovation. Wood framing members under load can be in compression or tension. Compression is when the piece is under load and the weight of the load is compressing it, as for example an upright post supporting a carrying timber. Tension is just the opposite, as when the piece is being stetched. A horizontal joist, supported at both ends and carrying a floor load, is in compression along the top edge and tension along the bottom edge, these stresses being at the maximum midway between supports.
If you must drill holes to run cable, locate the holes midway between top edge and bottom edge where the piece is in neither compression nor tension, and offset as much as possible from midway between supports to avoid compromising the framing. It is highly undesireable to notch such a beam at the edge.
To fish cable between two holes in wall material within the same framing pocket, drop an iron bolt tied to the end of a piece of string from the upper hole. Using a magnet attached to a dowel, capture the bolt inside the wall and draw it out the lower hole. This creates a pull rope which can be used to pull the cable.
If a motorized valve in a steam line has the right voltages but the motor won't turn, it is possible that the packing nut is too tight. Loosen it 1/4 turn and see if the valve becomes functional. Another possibility is that the gear train has become corroded and is sticking. Open the box and clean and oil all moving parts. Use an ohmmeter to see if the switch gear is working. These units are very expensive and worth spending some time on.
Three-way switches are less confusing to install or troubleshoot if a few simple principles are kept in mind. Two three-way switches plus any number of four-way switches in between function as a block like one single-pole switch. Between all switches are red and black "travellers" that serve as alternate hot paths. In the case of a switch loop, no neutral is required. For switched power to a fixture, a white neutral must accompany the travellers. When troubleshooting and the switches appear functional but the fixture won't power up, look for a problem in the neutral.
To lubricate the bearings of a furnace blower motor, it is often necessary to remove the squirrel cage fan from the motor shaft in order to access the motor, and this can be difficult. If available gear pullers will not fit, make a hardwood wedge to go behind the fan. Cut a slot in the middle of the wedge so that the two fingers can go past the shaft. For stubborn cases, sand and wax the wedge and drive it in hard. Then use a wood dowel and hammer to strike the end of the shaft with the whole assembly elevated off the bench. Prepare the shaft in advance with penetrating oil if necessary. Disassemble the motor and oil both bearings. If, after re-assembly, the motor appears to turn harder than ever, it is because one of the end housings has become bent and the bearings are out of line. Its not very difficult to straighten it and get everything going. When you are all done, you should be able to spin the shaft by hand and it will coast for awhile.
The National Electric Code requires that emergency lights are to be tested periodically and records kept. The time interval is not specified. Pressing the test button interrupts AC power so that the lights should go on. If they don't, put in new batteries. Then the lights will go on when you push the test button unless the new batteries are discharged, the bulbs are out, or there is a break in the wiring. If the new batteries are not charged the next time the unit is tested, the charger or relay may be bad. You don't need to buy a whole new box. Just change the circuit board.
If a fluorescent fixture is out, it is usually the bulbs. If it still won't light, verify that there is power to the ballast. If so, disconnect power, cut the wires near the ballast, mount a new ballast and reconnect, using the cut wires as a guide. If you lose track, there is a wiring diagram printed on the ballast, also the number and type of bulbs that the ballast is good for. If you upgrade from T-12 to the more energy efficient T-8 bulbs, the existing sockets are OK for either bulb, but the ballast must be changed. Running bulbs beyond the point where the ends are dark causes them to draw more current, overheating and ruining the ballast. It is more economical to change bulbs on a regular schedule rather than waiting for them to burn out.
A long, slender, straight blade screwdriver is sometimes known as an electrician's screwdriver, with good reason. It is essential for getting into tight places and provides a lot of control for tightening the cable connector in a deep box, and similar tasks. Since it has such a small shank, you can spin it between thumb and forefinger and quickly unscrew long threaded bolts.
Untrained personel believe to move a telephone to another location in the same room you should purchase couplings and add line cords. It is much better to use telephone wire and put in additional jacks as needed.
Track lighting is difficult to install, in part because different makes go together altogether differently and the parts are not at all interchangeable. The best approach is to study installation instructions carefully before proceeding or even planning out a job. Consult NEC Chapter four for circuit sizing.
When pulling wire that requires a lot of taping to connect to the pull rope or fish tape, wrap the wires in a thin layer of plastic such as a grocery bag or painter's plastic before taping. This allows you to apply the pressure needed to hold the conductors tightly together for the pull and makes for an easy cleanup because no sticky residue is left on the wires (Submitted by Michael Graves)
When installing a switch, receptacle or any other yoke-mounted device that requires additional support due to poor drywalling, don't buy those plastic spacers that are often difficult to work with. Simply wrap a piece of 14 AWG THHN wire around the shaft of a small Phillips screwdriver making it into the shape of a spring. Pull the coil off and cut to length. The coil should fit right over the mounting screw of the device and provide enough support so that you can tighten the screws to you heart's content. (Submitted by Michael Graves)